4023 - Typo in file(1) manpage and various others

          --- old/usr/src/man/man1/ksh93.1
          +++ new/usr/src/man/man1/ksh93.1
   1    1  '\" te
   2    2  .\" Copyright (c) 1982-2007 AT&T Knowledge Ventures
   3    3  .\" To view license terms, see http://www.opensource.org/licenses/cpl1.0.txt
   4    4  .\" Portions Copyright (c) 2009, Sun Microsystems, Inc.
   5      -.TH KSH93 1 "Aug 11, 2009"
        5 +.TH KSH93 1 "Sep 10, 2013"
   6    6  .SH NAME
   7    7  ksh93, rksh93 \- Korn Shell, a standard and restricted command and programming
   8    8  language
   9    9  .SH SYNOPSIS
  10   10  .LP
  11   11  .nf
  12   12  \fBksh93\fR [\fB\(+-abcefhikmnoprstuvxBCD\fR] [\fB-R\fR \fIfile\fR] [ \fB\(+-o\fR \fIoption\fR] ...
  13   13         [-] [\fIarg\fR ...]
  14   14  .fi
  15   15  

  16   16  .LP
  17   17  .nf
  18   18  \fBrksh93\fR [\fB\(+-abcefhikmnoprstuvxBCD\fR] [\fB-R\fR \fIfile\fR] [\fB\(+-o\fR \fIoption\fR] ...
  19   19         [-] [\fIarg\fR ...]
  20   20  .fi
  21   21  
  22   22  .SH DESCRIPTION
  23   23  .sp
  24   24  .LP
  25   25  \fBksh93\fR is a command and programming language that executes commands read
  26   26  from a terminal or a file. \fBrksh93\fR is a restricted version of the command
  27   27  interpreter \fBksh93\fR. \fBrksh93\fR is used to set up login names and
  28   28  execution environments whose capabilities are more controlled than those of the
  29   29  standard shell.
  30   30  .sp
  31   31  .LP
  32   32  See \fBInvocation\fR for the meaning of arguments to the shell.
  33   33  .SS "Definitions"
  34   34  .sp
  35   35  .LP
  36   36  A \fImetacharacter\fR is defined as one of the following characters:
  37   37  .sp
  38   38  .in +2
  39   39  .nf
  40   40  ; & ( ) | < > NEWLINE SPACE TAB
  41   41  .fi
  42   42  .in -2
  43   43  .sp
  44   44  
  45   45  .sp
  46   46  .LP
  47   47  A \fIblank\fR is a \fBTAB\fR or a \fBSPACE\fR.
  48   48  .sp
  49   49  .LP
  50   50  An \fIidentifier\fR is a sequence of letters, digits, or underscores starting
  51   51  with a letter or underscore. Identifiers are used as components of \fIvariable
  52   52  names\fR.
  53   53  .sp
  54   54  .LP
  55   55  A \fIvname\fR is a sequence of one or more identifiers separated by a period
  56   56  (\fB\&.\fR) and optionally preceded by a period (\fB\&.\fR). \fIvnames\fR are
  57   57  used as function and variable names.
  58   58  .sp
  59   59  .LP
  60   60  A \fIword\fR is a sequence of \fIcharacters\fR from the character set defined
  61   61  by the current locale, excluding non-quoted \fImetacharacters\fR.
  62   62  .sp
  63   63  .LP
  64   64  A \fIcommand\fR is a sequence of characters in the syntax of the shell
  65   65  language. The shell reads each command and carries out the desired action
  66   66  either directly or by invoking separate utilities. A built-in command is a
  67   67  command that is carried out by the shell itself without creating a separate
  68   68  process. Some commands are built-in purely for convenience and are not
  69   69  documented in this manual page. Built-ins that cause side effects in the shell
  70   70  environment and built-ins that are found before performing a path search (see
  71   71  \fBExecution\fR) are documented in this manual page. For historical reasons,
  72   72  some of these built-ins behave differently than other built-ins and are called
  73   73  special built-ins.
  74   74  .SS "Commands"
  75   75  .sp
  76   76  .LP
  77   77  A \fIsimple-command\fR is a list of variable assignments (see \fBVariable
  78   78  Assignments\fR) or a sequence of \fIblank\fR-separated words which can be
  79   79  preceded by a list of variable assignments. See the \fBEnvironment\fR section
  80   80  of this manual page.
  81   81  .sp
  82   82  .LP
  83   83  The first word specifies the name of the command to be executed. Except as
  84   84  specified in this section, the remaining words are passed as arguments to the
  85   85  invoked command. The command name is passed as argument 0. See \fBexec\fR(2).
  86   86  The \fIvalue\fR of a simple-command is its exit status. If it terminates
  87   87  normally, its value is \fB0\fR-\fB255\fR. If it terminates abnormally, its
  88   88  value is \fB256+\fR\fIsignum\fR. The name of the signal corresponding to the
  89   89  exit status can be obtained by way of the \fB-l\fR option of the kill built-in
  90   90  utility.
  91   91  .sp
  92   92  .LP
  93   93  A \fIpipeline\fR is a sequence of one or more commands separated by \fB|\fR.
  94   94  The standard output of each command but the last is connected by a
  95   95  \fBpipe\fR(2) to the standard input of the next command. Each command, except
  96   96  possibly the last, is run as a separate process. The shell waits for the last
  97   97  command to terminate. The exit status of a pipeline is the exit status of the
  98   98  last command unless the \fBpipefail\fR option is enabled. Each pipeline can be
  99   99  preceded by the reserved word\fB!\fR. This causes the exit status of the
 100  100  pipeline to become \fB0\fR if the exit status of the last command is
 101  101  \fBnon-zero\fR, and \fB1\fR if the exit status of the last command is \fB0\fR.
 102  102  .sp
 103  103  .LP
 104  104  A \fIlist\fR is a sequence of one or more pipelines separated by \fB;, &, |&,
 105  105  &&, or |\fR, and optionally terminated by \fB;, &,\fR or \fB|&\fR. Of these
 106  106  five symbols, \fB;, &\fR, and \fB|&\fR have equal precedence, which is lower
 107  107  than that of \fB&&\fR and \fB||\fR. The symbols \fB&&\fR and \fB||\fR also have
 108  108  equal precedence.
 109  109  .sp
 110  110  .LP
 111  111  A semicolon (\fB;\fR) causes sequential execution of the preceding pipeline. An
 112  112  ampersand (\fB&\fR) causes asynchronous execution of the preceding pipeline,
 113  113  that is, the shell does \fInot\fR wait for that pipeline to finish. The symbol
 114  114  \fB|&\fR causes asynchronous execution of the preceding pipeline with a two-way
 115  115  pipe established to the parent shell. The standard input and output of the
 116  116  spawned pipeline can be written to and read from by the parent shell by
 117  117  applying the redirection operators \fB<&\fR and \fB>&\fR with \fBarg p\fR to
 118  118  commands and by using \fB-p\fR option of the built-in commands \fBread\fR and
 119  119  \fBprint\fR. The symbol \fB&&\fR (\fB||\fR) causes the \fIlist\fR following it
 120  120  to be executed only if the preceding pipeline returns a zero (\fBnon-zero\fR)
 121  121  value. One or more NEWLINEs can appear in a \fIlist\fR instead of a semicolon,
 122  122  to delimit a command. The first \fIitem\fR of the first \fIpipeline\fR of a
 123  123  \fIlist\fR that is a simple command not beginning with a redirection, and not
 124  124  occurring within a \fBwhile\fR, \fBuntil\fR, or \fBif\fR \fIlist\fR , can be
 125  125  preceded by a semicolon. This semicolon is ignored unless the \fBshowme\fR
 126  126  option is enabled as described with the \fBset\fR built-in.
 127  127  .sp
 128  128  .LP
 129  129  A \fIcommand\fR is either a simple-command or one of commands in the following
 130  130  list. Unless otherwise stated, the value returned by a command is that of the
 131  131  last simple-command executed in the command.
 132  132  .sp
 133  133  .ne 2
 134  134  .na
 135  135  \fB\fBfor\fR \fIvname\fR \fB[ in\fR \fIword\fR \fB\&... ] ;do\fR \fIlist\fR
 136  136  \fB;done\fR\fR
 137  137  .ad
 138  138  .sp .6
 139  139  .RS 4n
 140  140  Each time a \fBfor\fR command is executed, \fIvname\fR is set to the next
 141  141  \fIword\fR taken from the \fBin\fR \fIword\fR list. If \fBin\fR \fIword ...\fR
 142  142  is omitted, the \fBfor\fR command executes the \fBdo\fR \fIlist\fR once for
 143  143  each positional parameter that is set starting from 1. Execution ends when
 144  144  there are no more words in the list. See \fBParameter Expansion\fR.
 145  145  .RE
 146  146  
 147  147  .sp
 148  148  .ne 2
 149  149  .na
 150  150  \fB\fB(( [\fR\fIexpr1\fR\fB] ; [\fR\fIexpr2\fR] ; [\fIexpr3\fR\fB] )) ;do\fR
 151  151  \fIlist\fR \fB;done\fR\fR
 152  152  .ad
 153  153  .sp .6
 154  154  .RS 4n
 155  155  The arithmetic expression \fIexpr1\fR is evaluated first. The arithmetic
 156  156  expression \fIexpr2\fR is repeatedly evaluated until it evaluates to \fBzero\fR
 157  157  and when \fBnon-zero\fR, \fIlist\fR is executed and the arithmetic expression
 158  158  \fIexpr3\fR evaluated. If any expression is omitted, then it behaves as if it
 159  159  evaluated to \fB1\fR. See \fBArithmetic Evaluation\fR.
 160  160  .RE
 161  161  
 162  162  .sp
 163  163  .ne 2
 164  164  .na
 165  165  \fB\fBselect\fR \fIvname\fR [ in \fIword\fR \fB\&... ] ;do\fR \fIlist\fR
 166  166  \fB;done\fR\fR
 167  167  .ad
 168  168  .sp .6
 169  169  .RS 4n
 170  170  A \fBselect\fR command prints on standard error (file descriptor 2) the set of
 171  171  \fIwords\fR, each preceded by a number. If \fBin\fR \fIword...\fR is omitted,
 172  172  the positional parameters starting from \fB1\fR are used instead. See
 173  173  \fBParameter Expansion\fR. The \fBPS3\fR prompt is printed and a line is read
 174  174  from the standard input. If this line consists of the number of one of the
 175  175  listed \fIword\fRs, then the value of the variable \fIvname\fR is set to the
 176  176  \fIword\fR corresponding to this number. If this line is empty, the selection
 177  177  list is printed again. Otherwise the value of the variable \fIvname\fR is set
 178  178  to \fBnull\fR. The contents of the line read from standard input is saved in
 179  179  the variable \fBREPLY\fR. The \fIlist\fR is executed for each selection until a
 180  180  break or \fBEOF\fR is encountered. If the \fBREPLY\fR variable is set to
 181  181  \fBnull\fR by the execution of \fIlist\fR, the selection list is printed before
 182  182  displaying the \fBPS3\fR prompt for the next selection.
 183  183  .RE
 184  184  
 185  185  .sp
 186  186  .ne 2
 187  187  .na
 188  188  \fB\fBcase\fR \fIword\fR \fBin [ [(]\fR \fIpattern\fR \fB[ |\fR \fIpattern\fR
 189  189  \fB] ... )\fR \fIlist\fR \fB;; ] ... esac\fR\fR
 190  190  .ad
 191  191  .sp .6
 192  192  .RS 4n
 193  193  A \fBcase\fR command executes the \fIlist\fR associated with the first
 194  194  \fIpattern\fR that matches \fIword\fR. The form of the patterns is the same as
 195  195  that used for file name generation. See \fBFile Name Generation\fR.
 196  196  .sp
 197  197  The \fB;;\fR operator causes execution of \fBcase\fR to terminate. If \fB;&\fR
 198  198  is used in place of \fB;;\fR the next subsequent list, if any, is executed.
 199  199  .RE
 200  200  
 201  201  .sp
 202  202  .ne 2
 203  203  .na
 204  204  \fB\fBif\fR \fIlist\fR \fB;then\fR \fIlist\fR \fB[ ;elif\fR \fIlist\fR
 205  205  \fB;then\fR \fIlist\fR ] \fB\&... [ ;else\fR \fIlist\fR \fB]\fR \fB;fi\fR\fR
 206  206  .ad
 207  207  .sp .6
 208  208  .RS 4n
 209  209  The \fIlist\fR following \fBif\fR is executed and, if it returns a \fBzero\fR
 210  210  exit status, the \fIlist\fR following the first \fBthen\fR is executed.
 211  211  Otherwise, the \fIlist\fR following \fBelif\fR is executed, and, if its value
 212  212  is \fBzero\fR, the \fIlist\fR following the next \fBthen\fR is executed.
 213  213  Failing each successive \fBelif\fR \fIlist\fR, the \fBelse\fR \fIlist\fR is
 214  214  executed. If the \fBif\fR \fIlist\fR has \fBnon-zero\fR exit status and there
 215  215  is no \fBelse\fR \fIlist\fR, then the \fBif\fR command returns a \fBzero\fR
 216  216  exit status.
 217  217  .RE
 218  218  
 219  219  .sp
 220  220  .ne 2
 221  221  .na
 222  222  \fB\fBwhile\fR \fIlist\fR \fB;do\fR \fIlist\fR \fB;done\fR\fR
 223  223  .ad
 224  224  .br
 225  225  .na
 226  226  \fBuntil \fIlist\fR \fB;do\fR \fIlist\fR \fB;done\fR\fR
 227  227  .ad
 228  228  .sp .6
 229  229  .RS 4n
 230  230  A \fBwhile\fR command repeatedly executes the while \fIlist\fR and, if the exit
 231  231  status of the last command in the list is zero, executes the \fBdo\fR
 232  232  \fIlist\fR, otherwise the loop terminates. If no commands in the \fBdo\fR
 233  233  \fIlist\fR are executed, then the \fBwhile\fR command returns a \fBzero\fR exit
 234  234  status, \fBuntil\fR can be used in place of \fBwhile\fR to negate the loop
 235  235  termination test.
 236  236  .RE
 237  237  
 238  238  .sp
 239  239  .ne 2
 240  240  .na
 241  241  \fB\fB((\fR\fIexpression\fR\fB))\fR\fR
 242  242  .ad
 243  243  .sp .6
 244  244  .RS 4n
 245  245  The \fIexpression\fR is evaluated using the rules for arithmetic evaluation
 246  246  described in this manual page. If the value of the arithmetic expression is
 247  247  \fBnon-zero\fR, the exit status is \fB0\fR. Otherwise the exit status is
 248  248  \fB1\fR.
 249  249  .RE
 250  250  
 251  251  .sp
 252  252  .ne 2
 253  253  .na
 254  254  \fB\fB(\fR\fIlist\fR\fB;)\fR\fR
 255  255  .ad
 256  256  .sp .6
 257  257  .RS 4n
 258  258  Execute list in a separate environment. If two adjacent open parentheses are
 259  259  needed for nesting, a SPACE must be inserted to avoid evaluation as an
 260  260  arithmetic command as described in this section.
 261  261  .sp
 262  262  \fIlist\fR is simply executed. Unlike the metacharacters, \fB(\fR and \fB)\fR,
 263  263  \fB{\fR and \fB}\fR are \fIreserved words\fR and must occur at the beginning of
 264  264  a line or after a \fB;\fR to be recognized.
 265  265  .RE
 266  266  
 267  267  .sp
 268  268  .ne 2
 269  269  .na
 270  270  \fB\fB[[\fR \fIexpression\fR \fB]]\fR\fR
 271  271  .ad
 272  272  .sp .6
 273  273  .RS 4n
 274  274  Evaluates \fIexpression\fR and returns a \fBzero\fR exit status when
 275  275  \fIexpression\fR is true. See \fBConditional Expressions\fR for a description
 276  276  of \fIexpression\fR.
 277  277  .RE
 278  278  
 279  279  .sp
 280  280  .ne 2
 281  281  .na
 282  282  \fB\fBfunction\fR \fIvarname\fR \fB{\fR \fIlist\fR \fB;}\fR\fR
 283  283  .ad
 284  284  .br
 285  285  .na
 286  286  \fB\fIvarname\fR \fB() {\fR \fIlist\fR \fB;}\fR\fR
 287  287  .ad
 288  288  .sp .6
 289  289  .RS 4n
 290  290  Define a function which is referenced by \fIvarname\fR. A function whose
 291  291  \fIvarname\fR contains a \fB\&.\fR is called a discipline function and the
 292  292  portion of the \fIvarname\fR preceding the last \fB\&.\fR must refer to an
 293  293  existing variable.
 294  294  .sp
 295  295  The body of the function is the \fIlist\fR of commands between \fB{\fR and
 296  296  \fB}\fR. A function defined with the function \fIvarname\fR syntax can also be
 297  297  used as an argument to the \fB\&.\fR special built-in command to get the
 298  298  equivalent behavior as if the \fIvarname\fR\fB()\fR syntax were used to define
 299  299  it. See \fBFunctions\fR.
 300  300  .RE
 301  301  
 302  302  .sp
 303  303  .ne 2
 304  304  .na
 305  305  \fB\fBtime [\fR \fIpipeline\fR \fB]\fR\fR
 306  306  .ad
 307  307  .sp .6
 308  308  .RS 4n
 309  309  If \fIpipeline\fR is omitted, the user and system time for the current shell
 310  310  and completed child processes is printed on standard error. Otherwise,
 311  311  \fIpipeline\fR is executed and the elapsed time as well as the user and system
 312  312  time are printed on standard error. The \fBTIMEFORMAT\fR variable can be set to
 313  313  a format string that specifies how the timing information should be displayed.
 314  314  See \fBShell Variables\fR for a description of the \fBTIMEFORMAT\fR variable.
 315  315  .RE
 316  316  
 317  317  .sp
 318  318  .LP
 319  319  The following reserved words are recognized as reserved only when they are the
 320  320  first word of a command and are not quoted:
 321  321  .br
 322  322  .in +2
 323  323  \fBcase\fR
 324  324  .in -2
 325  325  .br
 326  326  .in +2
 327  327  \fBdo\fR
 328  328  .in -2
 329  329  .br
 330  330  .in +2
 331  331  \fBdone\fR
 332  332  .in -2
 333  333  .br
 334  334  .in +2
 335  335  \fBelse\fR
 336  336  .in -2
 337  337  .br
 338  338  .in +2
 339  339  \fBelif\fR
 340  340  .in -2
 341  341  .br
 342  342  .in +2
 343  343  \fBesac\fR
 344  344  .in -2
 345  345  .br
 346  346  .in +2
 347  347  \fBfor\fR
 348  348  .in -2
 349  349  .br
 350  350  .in +2
 351  351  \fBfi\fR
 352  352  .in -2
 353  353  .br
 354  354  .in +2
 355  355  \fBfunction\fR
 356  356  .in -2
 357  357  .br
 358  358  .in +2
 359  359  \fBif\fR
 360  360  .in -2
 361  361  .br
 362  362  .in +2
 363  363  \fBselect\fR
 364  364  .in -2
 365  365  .br
 366  366  .in +2
 367  367  \fBthen\fR
 368  368  .in -2
 369  369  .br
 370  370  .in +2
 371  371  \fBtime\fR
 372  372  .in -2
 373  373  .br
 374  374  .in +2
 375  375  \fBuntil\fR
 376  376  .in -2
 377  377  .br
 378  378  .in +2
 379  379  \fBwhile\fR
 380  380  .in -2
 381  381  .br
 382  382  .in +2
 383  383  \fB{ }\fR
 384  384  .in -2
 385  385  .br
 386  386  .in +2
 387  387  \fB[[ ]]\fR
 388  388  .in -2
 389  389  .br
 390  390  .in +2
 391  391  \fB!\fR
 392  392  .in -2
 393  393  .SS "Variable Assignments"
 394  394  .sp
 395  395  .LP
 396  396  One or more variable assignments can start a simple command or can be arguments
 397  397  to the \fBtypeset\fR, \fBexport\fR, or \fBreadonly\fR special built-in
 398  398  commands. The syntax for an \fIassignment\fR is of the form:
 399  399  .sp
 400  400  .ne 2
 401  401  .na
 402  402  \fB\fIvarname\fR\fB=\fR\fIword\fR\fR
 403  403  .ad
 404  404  .br
 405  405  .na
 406  406  \fB\fIvarname\fR\fB[\fR\fIword\fR\fB]=\fR\fIword\fR\fR
 407  407  .ad
 408  408  .sp .6
 409  409  .RS 4n
 410  410  No space is permitted between \fIvarname\fR and the \fB=\fR or between \fB=\fR
 411  411  and \fIword\fR.
 412  412  .RE
 413  413  
 414  414  .sp
 415  415  .ne 2
 416  416  .na
 417  417  \fB\fIvarname\fR\fB=(\fR\fIassignlist\fR\fB)\fR\fR
 418  418  .ad
 419  419  .sp .6
 420  420  .RS 4n
 421  421  No space is permitted between \fIvarname\fR and the \fB=\fR. An
 422  422  \fIassignlist\fR can be one of the following:
 423  423  .sp
 424  424  .ne 2
 425  425  .na
 426  426  \fB\fIword ...\fR\fR
 427  427  .ad
 428  428  .sp .6
 429  429  .RS 4n
 430  430  Indexed array assignment.
 431  431  .RE
 432  432  
 433  433  .sp
 434  434  .ne 2
 435  435  .na
 436  436  \fB\fB[\fR\fIword\fR\fB]=\fR\fIword ...\fR\fR
 437  437  .ad
 438  438  .sp .6
 439  439  .RS 4n
 440  440  Associative array assignment. If prefixed by \fBtypeset\fR \fB-a\fR, creates an
 441  441  indexed array instead.
 442  442  .RE
 443  443  
 444  444  .sp
 445  445  .ne 2
 446  446  .na
 447  447  \fB\fIassignment ...\fR\fR
 448  448  .ad
 449  449  .sp .6
 450  450  .RS 4n
 451  451  Compound variable assignment. This creates a compound variable \fIvarname\fR
 452  452  with sub-variables of the form \fIvarname.name\fR, where \fIname\fR is the name
 453  453  portion of assignment. The value of \fIvarname\fR contains all the assignment
 454  454  elements. Additional assignments made to sub-variables of \fIvarname\fR are
 455  455  also displayed as part of the value of \fIvarname\fR. If no \fIassignment\fRs
 456  456  are specified, \fIvarname\fR is a compound variable allowing subsequence child
 457  457  elements to be defined.
 458  458  .RE
 459  459  
 460  460  .sp
 461  461  .ne 2
 462  462  .na
 463  463  \fB\fBtypeset [\fR\fIoptions\fR] \fIassignment\fR \fB\&...\fR\fR
 464  464  .ad
 465  465  .sp .6
 466  466  .RS 4n
 467  467  Nested variable assignment. Multiple assignments can be specified by separating
 468  468  each of them with a \fB;\fR. The previous value is unset before the assignment.
 469  469  .RE
 470  470  
 471  471  In addition, a \fB+=\fR can be used in place of the \fB=\fR to signify adding
 472  472  to or appending to the previous value. When \fB+=\fR is applied to an
 473  473  arithmetic type, \fIword\fR is evaluated as an arithmetic expression and added
 474  474  to the current value. When applied to a string variable, the value defined by
 475  475  \fIword\fR is appended to the value. For compound assignments, the previous
 476  476  value is not unset and the new values are appended to the current ones provided
 477  477  that the types are compatible.
 478  478  .RE
 479  479  
 480  480  .SS "Comments"
 481  481  .sp
 482  482  .LP
 483  483  A word beginning with \fB#\fR causes that word and all the following characters
 484  484  up to a NEWLINE to be commented, or ignored.
 485  485  .SS "Aliasing"
 486  486  .sp
 487  487  .LP
 488  488  The first word of each command is replaced by the text of an alias if an alias
 489  489  for this word has been defined. An alias name consists of any number of
 490  490  characters excluding metacharacters, quoting characters, file expansion
 491  491  characters, parameter expansion characters, command substitution characters,
 492  492  and \fB=\fR. The replacement string can contain any valid shell script
 493  493  including the metacharacters listed in the \fBCommands\fR section. The first
 494  494  word of each command in the replaced text, other than any that are in the
 495  495  process of being replaced, are tested for aliases. If the last character of the
 496  496  alias value is a BLANK then the word following the alias is also checked for
 497  497  alias substitution.
 498  498  .sp
 499  499  .LP
 500  500  Aliases can be used to redefine built-in commands but cannot be used to
 501  501  redefine the reserved words listed in the \fBCommands\fR section. Aliases can
 502  502  be created and listed with the alias command and can be removed with the
 503  503  \fBunalias\fR command.
 504  504  .sp
 505  505  .LP
 506  506  Aliasing is performed when scripts are read, not while they are executed. For
 507  507  an alias to take effect, the \fBalias\fR definition command has to be executed
 508  508  before the command which references the alias is read. The following aliases
 509  509  are compiled into the shell but can be unset or redefined:
 510  510  .sp
 511  511  .in +2
 512  512  .nf
 513  513  autoload='typeset -fu'
 514  514  command='command '
 515  515  fc=hist
 516  516  float='typeset -lE'
 517  517  functions='typeset -f'
 518  518  hash='alias -t --'
 519  519  history='hist -l'
 520  520  integer='typeset -li'
 521  521  nameref='typeset -n'
 522  522  nohup='nohup '
 523  523  r='hist -s'
 524  524  redirect='command exec'
 525  525  source='command .'
 526  526  stop='kill -s STOP'
 527  527  suspend='kill -s STOP $$'
 528  528  times='{ { time;} 2>&1;}'
 529  529  type='whence -v'
 530  530  .fi
 531  531  .in -2
 532  532  .sp
 533  533  
 534  534  .SS "Tilde Substitution"
 535  535  .sp
 536  536  .LP
 537  537  After alias substitution is performed, each word is checked to see if it begins
 538  538  with an unquoted tilde (\fB~\fR). For tilde substitution, \fIword\fR also
 539  539  refers to the \fIword\fR portion of parameter expansion. See \fBParameter
 540  540  Expansion\fR.
 541  541  .sp
 542  542  .LP
 543  543  If it does, the word up to a \fB/\fR is checked to see if it matches a user
 544  544  name in the password database. If a match is found, the \fB~\fR and the matched
 545  545  login name are replaced by the login directory of the matched user. If no match
 546  546  is found, the original text is left unchanged. A \fB~\fR by itself, or in front
 547  547  of a \fB/\fR, is replaced by \fB$HOME\fR. A \fB~\fR followed by a \fB+\fR or
 548  548  \fB-\fR is replaced by the value of \fB$PWD\fR and \fB$OLDPWD\fR respectively.
 549  549  .sp
 550  550  .LP
 551  551  In addition, when expanding a \fIvariable assignment\fR, tilde substitution is
 552  552  attempted when the value of the assignment begins with a \fB~\fR, and when a
 553  553  \fB~\fR appears after a colon (\fB:\fR). The \fB:\fR also terminates a \fB~\fR
 554  554  login name.
 555  555  .SS "Command Substitution"
 556  556  .sp
 557  557  .LP
 558  558  The standard output from a command enclosed in parentheses preceded by a dollar
 559  559  sign (\fB$\fR) or a pair of grave accents (\fB``\fR) can be used as part or all
 560  560  of a word. Trailing NEWLINEs are removed. In the second (obsolete) form, the
 561  561  string between the quotes is processed for special quoting characters before
 562  562  the command is executed. See \fBQuoting\fR.
 563  563  .sp
 564  564  .LP
 565  565  The command substitution \fB$(cat file)\fR can be replaced by the equivalent
 566  566  but faster \fB$(<file)\fR. The command substitution \fB$(\fR\fIn\fR\fB<#)\fR
 567  567  expands to the current byte offset for file descriptor \fIn\fR.
 568  568  .SS "Arithmetic Substitution"
 569  569  .sp
 570  570  .LP
 571  571  An arithmetic expression enclosed in double parentheses preceded by a dollar
 572  572  sign ( \fB$((\fR\fIarithmetic_expression\fR\fB))\fR) is replaced by the value
 573  573  of the arithmetic expression within the double parentheses.
 574  574  .SS "Process Substitution"
 575  575  .sp
 576  576  .LP
 577  577  Process substitution is only available on versions of the UNIX operating system
 578  578  that support the \fB/dev/fd\fR directory for naming open files.
 579  579  .sp
 580  580  .LP
 581  581  Each command argument of the form \fB<(\fR\fIlist\fR\fB)\fR or
 582  582  \fB>(\fR\fIlist\fR\fB)\fR runs process \fIlist\fR asynchronously connected to
 583  583  some file in \fB/dev/fd\fR. The name of this file becomes the argument to the
 584  584  command. If the form with \fB>\fR is selected then writing on this file
 585  585  provides input for \fIlist\fR. If \fB<\fR is used, then the file passed as an
 586  586  argument contains the output of the \fIlist\fR process.
 587  587  .sp
 588  588  .LP
 589  589  For example,
 590  590  .sp
 591  591  .in +2
 592  592  .nf
 593  593  paste <(cut -f1 \fIfile1\fR) <(cut -f3 \fIfile2\fR) | tee \e
 594  594       >(\fIprocess1\fR) >(\fIprocess2\fR)
 595  595  .fi
 596  596  .in -2
 597  597  .sp
 598  598  
 599  599  .sp
 600  600  .LP
 601  601  \fBcut\fRs fields 1 and 3 from the files \fIfile1\fR and \fIfile2\fR
 602  602  respectively, \fBpaste\fRs the results together, and sends it to the processes
 603  603  \fIprocess1\fR and \fIprocess2\fR. It also displays the results to the standard
 604  604  output. The file, which is passed as an argument to the command, is a UNIX
 605  605  \fBpipe\fR(2). Programs that expect to \fBlseek\fR(2) on the file do not work.
 606  606  .SS "Parameter Expansion"
 607  607  .sp
 608  608  .LP
 609  609  A parameter is a variable, one or more digits, or any of the characters
 610  610  \fB*\fR, \fB@\fR, \fB#\fR, \fB?\fR, \fB-\fR, \fB$\fR, and \fB!\fR. A variable
 611  611  is denoted by a \fIvname\fR. To create a variable whose \fIvname\fR contains a
 612  612  \fB\&.\fR, a variable whose \fBvname\fR consists of everything before the
 613  613  last . must already exist. A variable has a value and zero or more attributes.
 614  614  Variables can be assigned values and attributes by using the \fBtypeset\fR
 615  615  special built-in command. The attributes supported by the shell are described
 616  616  later with the \fBtypeset\fR special built-in command. Exported variables pass
 617  617  values and attributes to the environment.
 618  618  .sp
 619  619  .LP
 620  620  The shell supports both indexed and associative arrays. An element of an array
 621  621  variable is referenced by a subscript. A subscript for an indexed array is
 622  622  denoted by an arithmetic expression, (see \fBArithmetic Evaluation\fR), between
 623  623  a \fB[\fR and a \fB]\fR. Use \fBset -A\fR \fIvname value ...\fR to assign
 624  624  values to an indexed array. The value of all subscripts must be in the range of
 625  625  \fB0\fR through \fB1,048,575\fR. Indexed arrays do not need to be declared. Any
 626  626  reference to a variable with a valid subscript is legal and an array is created
 627  627  if necessary.
 628  628  .sp
 629  629  .LP
 630  630  An associative array is created with the \fB-A\fR option to \fBtypeset\fR. A
 631  631  subscript for an associative array is denoted by a string enclosed between
 632  632  \fB[\fR and \fB]\fR.
 633  633  .sp
 634  634  .LP
 635  635  Referencing any array without a subscript is equivalent to referencing the
 636  636  array with subscript \fB0\fR.
 637  637  .sp
 638  638  .LP
 639  639  The value of a variable can be assigned by:
 640  640  .sp
 641  641  .in +2
 642  642  .nf
 643  643  \fIvname\fR=\fIvalue\fR [\fIvname\fR=\fIvalue\fR] ...
 644  644  .fi
 645  645  .in -2
 646  646  .sp
 647  647  
 648  648  .sp
 649  649  .LP
 650  650  or
 651  651  .sp
 652  652  .in +2
 653  653  .nf
 654  654  \fIvname\fR[\fIsubscript\fR]=\fIvalue\fR [\fIvname\fR[\fIsubscript\fR]=\fIvalue\fR] ...
 655  655  .fi
 656  656  .in -2
 657  657  .sp
 658  658  
 659  659  .sp
 660  660  .LP
 661  661  No space is allowed before or after the \fB=\fR. A \fInameref\fR is a variable
 662  662  that is a reference to another variable. A \fInameref\fR is created with the
 663  663  \fB-n\fR attribute of \fBtypeset\fR. The value of the variable at the time of
 664  664  the \fBtypeset\fR command becomes the variable that is referenced whenever the
 665  665  \fInameref\fR variable is used. The name of a \fInameref\fR cannot contain a
 666  666  dot (\fI\&.\fR). When a variable or function name contains a \fB\&.,\fR and the
 667  667  portion of the name up to the first \fB\&.\fR matches the name of a
 668  668  \fInameref\fR, the variable referred to is obtained by replacing the
 669  669  \fInameref\fR portion with the name of the variable referenced by the
 670  670  \fInameref\fR. If a \fInameref\fR is used as the index of a \fBfor\fR loop, a
 671  671  name reference is established for each item in the list. A \fInameref\fR
 672  672  provides a convenient way to refer to the variable inside a function whose name
 673  673  is passed as an argument to a function. For example, if the name of a variable
 674  674  is passed as the first argument to a function, the command
 675  675  .sp
 676  676  .in +2
 677  677  .nf
 678  678   typeset -n var=$1
 679  679  .fi
 680  680  .in -2
 681  681  .sp
 682  682  
 683  683  .sp
 684  684  .LP
 685  685  inside the function causes references and assignments to \fIvar\fR to be
 686  686  references and assignments to the variable whose name has been passed to the
 687  687  function. If either of the floating point attributes, \fB-E\fR, or \fB-F\fR, or
 688  688  the integer attribute, \fB-i\fR, is set for \fIvname\fR, then the \fIvalue\fR
 689  689  is subject to arithmetic evaluation as described in this manual page.
 690  690  Positional parameters, parameters denoted by a number, can be assigned values
 691  691  with the \fBset\fR special built-in command. Parameter \fB$0\fR is set from
 692  692  argument zero when the shell is invoked. The character \fB$\fR is used to
 693  693  introduce substitutable parameters.
 694  694  .sp
 695  695  .ne 2
 696  696  .na
 697  697  \fB\fB${\fR\fIparameter\fR\fB}\fR\fR
 698  698  .ad
 699  699  .sp .6
 700  700  .RS 4n
 701  701  The shell reads all the characters from \fB${\fR to the matching \fB}\fR as
 702  702  part of the same word even if it contains braces or metacharacters. The value,
 703  703  if any, of the parameter is substituted. The braces are required when
 704  704  \fIparameter\fR is followed by a letter, digit, or underscore that is not to be
 705  705  interpreted as part of its name, when the variable name contains a \fB\&.\fR,
 706  706  or when a variable is subscripted. If \fIparameter\fR is one or more digits
 707  707  then it is a positional parameter. A positional parameter of more than one
 708  708  digit must be enclosed in braces. If \fIparameter\fR is \fB*\fR or \fB@\fR,
 709  709  then all the positional parameters, starting with \fB$1\fR, are substituted and
 710  710  separated by a field separator character. If an array \fIvname\fR with
 711  711  subscript \fB*\fR or \fB@\fR is used, then the value for each of the elements
 712  712  is substituted, separated by the first character of the value of \fBIFS\fR.
 713  713  .RE
 714  714  
 715  715  .sp
 716  716  .ne 2
 717  717  .na
 718  718  \fB\fB${#\fR\fIparameter\fR\fB}\fR\fR
 719  719  .ad
 720  720  .sp .6
 721  721  .RS 4n
 722  722  If \fIparameter\fR is \fB*\fR or \fB@\fR, the number of positional parameters
 723  723  is substituted. Otherwise, the length of the value of the \fIparameter\fR is
 724  724  substituted.
 725  725  .RE
 726  726  
 727  727  .sp
 728  728  .ne 2
 729  729  .na
 730  730  \fB\fB${#\fR\fIvname\fR\fB[*]}\fR\fR
 731  731  .ad
 732  732  .br
 733  733  .na
 734  734  \fB\fB${#\fR\fIvname\fR\fB[@]}\fR\fR
 735  735  .ad
 736  736  .sp .6
 737  737  .RS 4n
 738  738  The number of elements in the array \fIvname\fR is substituted.
 739  739  .RE
 740  740  
 741  741  .sp
 742  742  .ne 2
 743  743  .na
 744  744  \fB\fB${!\fR\fIvname\fR\fB}\fR\fR
 745  745  .ad
 746  746  .sp .6
 747  747  .RS 4n
 748  748  Expands to the name of the variable referred to by \fIvname\fR. This is
 749  749  \fIvname\fR except when \fIvname\fR is a name reference.
 750  750  .RE
 751  751  
 752  752  .sp
 753  753  .ne 2
 754  754  .na
 755  755  \fB\fB${!\fR\fIvname\fR\fB[\fR\fIsubscript\fR\fB]}\fR\fR
 756  756  .ad
 757  757  .sp .6
 758  758  .RS 4n
 759  759  Expands to name of the subscript unless \fIsubscript\fR is \fB*\fR or \fB@\fR.
 760  760  When \fIsubscript\fR is \fB*\fR, the list of array subscripts for \fIvname\fR
 761  761  is generated. For a variable that is not an array, the value is \fB0\fR if the
 762  762  variable is set. Otherwise it is \fBnull\fR. When \fIsubscript\fR is \fB@\fR,
 763  763  it is the same as \fB$ {\fR\fIvname\fR\fB[\fR\fI*\fR\fB]}\fR, except that when
 764  764  used in double quotes, each array subscript yields a separate argument.
 765  765  .RE
 766  766  
 767  767  .sp
 768  768  .ne 2
 769  769  .na
 770  770  \fB\fB${!\fR\fIprefix\fR\fB*}\fR\fR
 771  771  .ad
 772  772  .sp .6
 773  773  .RS 4n
 774  774  Expands to the names of the variables whose names begin with \fIprefix\fR.
 775  775  .RE
 776  776  
 777  777  .sp
 778  778  .ne 2
 779  779  .na
 780  780  \fB\fB${\fR\fIparameter\fR\fB:-\fR\fIword\fR\fB}\fR\fR
 781  781  .ad
 782  782  .sp .6
 783  783  .RS 4n
 784  784  If \fIparameter\fR is set and is non-null then substitute its value. Otherwise
 785  785  substitute \fIword\fR.
 786  786  .sp
 787  787  \fIword\fR is not evaluated unless it is to be used as the substituted string.
 788  788  .sp
 789  789  In the following example, \fBpwd\fR is executed only if \fBd\fR is not set or
 790  790  is NULL:
 791  791  .sp
 792  792  .in +2
 793  793  .nf
 794  794  print ${d:-$(pwd)}
 795  795  .fi
 796  796  .in -2
 797  797  .sp
 798  798  
 799  799  If the colon (\fB:\fR ) is omitted from the expression, the shell only checks
 800  800  whether \fIparameter\fR is set or not.
 801  801  .RE
 802  802  
 803  803  .sp
 804  804  .ne 2
 805  805  .na
 806  806  \fB\fB${\fR\fIparameter\fR\fB:=\fR\fIword\fR\fB}\fR\fR
 807  807  .ad
 808  808  .sp .6
 809  809  .RS 4n
 810  810  If \fIparameter\fR is not set or is \fBnull\fR, set it to \fIword\fR. The value
 811  811  of the parameter is then substituted. Positional parameters cannot be assigned
 812  812  to in this way.
 813  813  .sp
 814  814  \fIword\fR is not evaluated unless it is to be used as the substituted string.
 815  815  .sp
 816  816  In the following example, \fBpwd\fR is executed only if \fBd\fR is not set or
 817  817  is NULL:
 818  818  .sp
 819  819  .in +2
 820  820  .nf
 821  821  print ${d:-$(pwd)}
 822  822  .fi
 823  823  .in -2
 824  824  .sp
 825  825  
 826  826  If the colon (\fB:\fR) is omitted from the expression, the shell only checks
 827  827  whether \fIparameter\fR is set or not.
 828  828  .RE
 829  829  
 830  830  .sp
 831  831  .ne 2
 832  832  .na
 833  833  \fB\fB${\fR\fIparameter\fR\fB:?\fR\fIword\fR\fB}\fR\fR
 834  834  .ad
 835  835  .sp .6
 836  836  .RS 4n
 837  837  If \fIparameter\fR is set and is non-null, substitute its value. Otherwise,
 838  838  print \fIword\fR and exit from the shell , if the shell is not interactive. If
 839  839  \fIword\fR is omitted then a standard message is printed.
 840  840  .sp
 841  841  \fIword\fR is not evaluated unless it is to be used as the substituted string.
 842  842  .sp
 843  843  In the following example, \fBpwd\fR is executed only if \fBd\fR is not set or
 844  844  is NULL:
 845  845  .sp
 846  846  .in +2
 847  847  .nf
 848  848  print ${d:-$(pwd)}
 849  849  .fi
 850  850  .in -2
 851  851  .sp
 852  852  
 853  853  If the colon (\fB:\fR ) is omitted from the expression, the shell only checks
 854  854  whether \fIparameter\fR is set or not.
 855  855  .RE
 856  856  
 857  857  .sp
 858  858  .ne 2
 859  859  .na
 860  860  \fB\fB${\fR\fIparameter\fR\fB:+\fR\fIword\fR\fB}\fR\fR
 861  861  .ad
 862  862  .sp .6
 863  863  .RS 4n
 864  864  If \fIparameter\fR is set and is non-null, substitute \fIword\fR. Otherwise
 865  865  substitute nothing.
 866  866  .sp
 867  867  \fIword\fR is not evaluated unless it is to be used as the substituted string.
 868  868  .sp
 869  869  In the following example, \fBpwd\fR is executed only if \fBd\fR is not set or
 870  870  is NULL:
 871  871  .sp
 872  872  .in +2
 873  873  .nf
 874  874  print ${d:-$(pwd)}
 875  875  .fi
 876  876  .in -2
 877  877  .sp
 878  878  
 879  879  If the colon (\fB:\fR) is omitted from the expression, the shell only checks
 880  880  whether \fIparameter\fR is set or not.
 881  881  .RE
 882  882  
 883  883  .sp
 884  884  .ne 2
 885  885  .na
 886  886  \fB\fB${\fR\fIparameter\fR\fB:\fR\fIoffset\fR:\fIlength\fR}\fR
 887  887  .ad
 888  888  .br
 889  889  .na
 890  890  \fB\fB${\fR\fIparameter\fR\fB:\fR\fIoffset\fR\fB}\fR\fR
 891  891  .ad
 892  892  .sp .6
 893  893  .RS 4n
 894  894  Expands to the portion of the value of \fIparameter\fR starting at the
 895  895  character (counting from \fB0\fR) determined by expanding offset as an
 896  896  arithmetic expression and consisting of the number of characters determined by
 897  897  the arithmetic expression defined by \fIlength\fR.
 898  898  .sp
 899  899  In the second form, the remainder of the value is used. A negative offset
 900  900  counts backwards from the end of \fIparameter\fR.
 901  901  .sp
 902  902  One or more BLANKs is required in front of a minus sign to prevent the shell
 903  903  from interpreting the operator as \fB:-\fR. If parameter is \fB*\fR or \fB@\fR,
 904  904  or is an array name indexed by \fB*\fR or \fB@\fR, then \fIoffset\fR and
 905  905  \fIlength\fR refer to the array index and number of elements respectively. A
 906  906  negative \fIoffset\fR is taken relative to one greater than the highest
 907  907  subscript for indexed arrays. The order for associative arrays is unspecified.
 908  908  .RE
 909  909  
 910  910  .sp
 911  911  .ne 2
 912  912  .na
 913  913  \fB\fB${\fR\fIparameter\fR\fB#\fR\fIpattern\fR\fB}\fR\fR
 914  914  .ad
 915  915  .br
 916  916  .na
 917  917  \fB\fB${\fR\fIparameter\fR\fB##\fR\fIpattern\fR\fB}\fR\fR
 918  918  .ad
 919  919  .sp .6
 920  920  .RS 4n
 921  921  If the shell \fIpattern\fR matches the beginning of the value of
 922  922  \fIparameter\fR, then the value of this expansion is the value of the
 923  923  \fIparameter\fR with the matched portion deleted. Otherwise the value of this
 924  924  \fIparameter\fR is substituted. In the first form the smallest matching
 925  925  \fIpattern\fR is deleted and in the second form the largest matching
 926  926  \fIpattern\fR is deleted. When \fIparameter\fR is \fB@\fR, \fB*\fR, or an array
 927  927  variable with subscript \fB@\fR or \fB*\fR, the substring operation is applied
 928  928  to each element in turn.
 929  929  .RE
 930  930  
 931  931  .sp
 932  932  .ne 2
 933  933  .na
 934  934  \fB\fB${\fR\fIparameter\fR\fB%\fR\fIpattern\fR\fB}\fR\fR
 935  935  .ad
 936  936  .br
 937  937  .na
 938  938  \fB\fB${\fR\fIparameter\fR\fB%%\fR\fIpattern\fR\fB}\fR\fR
 939  939  .ad
 940  940  .sp .6
 941  941  .RS 4n
 942  942  If the shell \fIpattern\fR matches the end of the value of \fIparameter\fR,
 943  943  then the value of this expansion is the value of the parameter with the matched
 944  944  part deleted. Otherwise substitute the value of \fIparameter\fR. In the first
 945  945  form the smallest matching pattern is deleted, and in the second form the
 946  946  largest matching pattern is deleted. When parameter is \fB@\fR, \fB*\fR, or an
 947  947  array variable with subscript \fB@\fR or \fB*\fR, the substring operation is
 948  948  applied to each element in turn.
 949  949  .RE
 950  950  
 951  951  .sp
 952  952  .ne 2
 953  953  .na
 954  954  \fB\fB${\fR\fIparameter\fR\fB/\fR\fIpattern\fR\fB/\fR\fIstring\fR\fB}\fR\fR
 955  955  .ad
 956  956  .br
 957  957  .na
 958  958  \fB\fB${\fR\fIparameter\fR\fB//\fR\fIpattern\fR\fB/\fR\fIstring\fR\fB}\fR\fR
 959  959  .ad
 960  960  .br
 961  961  .na
 962  962  \fB\fB${\fR\fIparameter\fR\fB/#\fR\fIpattern\fR\fB/\fR\fIstring\fR\fB}\fR\fR
 963  963  .ad
 964  964  .br
 965  965  .na
 966  966  \fB\fB${\fR\fIparameter\fR\fB/%\fR\fIpattern\fR\fB/\fR\fIstring\fR\fB}\fR\fR
 967  967  .ad
 968  968  .sp .6
 969  969  .RS 4n
 970  970  Expands \fIparameter\fR and replaces the longest match of \fIpattern\fR with
 971  971  the specified \fIstring\fR. Each occurrence of \fB\e\fR\fIn\fR in \fIstring\fR
 972  972  is replaced by the portion of \fIparameter\fR that matches the \fIn\fR\fBth\fR
 973  973  sub-pattern.
 974  974  .sp
 975  975  When \fIstring\fR is null, the \fIpattern\fR is deleted and the \fB/\fR in
 976  976  front of string can be omitted. When \fIparameter\fR is \fB@\fR, \fB*\fR, or an
 977  977  array variable with subscript \fB@\fR or \fB*\fR, the substitution operation is
 978  978  applied to each element in turn. In this case, the \fIstring\fR portion of
 979  979  \fIword\fR is re-evaluated for each element.
 980  980  .sp
 981  981  In the first form, only the first occurrence of \fIpattern\fR is replaced.
 982  982  .sp
 983  983  In the second form, each match for \fIpattern\fR is replaced by the specified
 984  984  \fIstring\fR.
 985  985  .sp
 986  986  The third form restricts the pattern match to the beginning of the
 987  987  \fIstring\fR.
 988  988  .sp
 989  989  The fourth form restricts the pattern match to the end of the \fIstring\fR.
 990  990  .RE
 991  991  
 992  992  .sp
 993  993  .LP
 994  994  The following parameters are automatically set by the shell:
 995  995  .sp
 996  996  .ne 2
 997  997  .na
 998  998  \fB\fB#\fR\fR
 999  999  .ad
1000 1000  .RS 19n
1001 1001  The number of positional parameters in decimal.
1002 1002  .RE
1003 1003  
1004 1004  .sp
1005 1005  .ne 2
1006 1006  .na
1007 1007  \fB\fB-\fR\fR
1008 1008  .ad
1009 1009  .RS 19n
1010 1010  Options supplied to the shell on invocation or by the \fBset\fR command.
1011 1011  .RE
1012 1012  
1013 1013  .sp
1014 1014  .ne 2
1015 1015  .na
1016 1016  \fB\fB?\fR\fR
1017 1017  .ad
1018 1018  .RS 19n
1019 1019  The decimal value returned by the last executed command.
1020 1020  .RE
1021 1021  
1022 1022  .sp
1023 1023  .ne 2
1024 1024  .na
1025 1025  \fB\fB$\fR\fR
1026 1026  .ad
1027 1027  .RS 19n
1028 1028  The process number of this shell.
1029 1029  .RE
1030 1030  
1031 1031  .sp
1032 1032  .ne 2
1033 1033  .na
1034 1034  \fB\fB_\fR\fR
1035 1035  .ad
1036 1036  .RS 19n
1037 1037  Initially, the value of \fB_\fR is the absolute pathname of the shell or script
1038 1038  being executed as passed in the environment. It is subsequently assigned the
1039 1039  last argument of the previous command.
1040 1040  .sp
1041 1041  This parameter is not set for commands which are asynchronous. This parameter
1042 1042  is also used to hold the name of the matching \fBMAIL\fR file when checking for
1043 1043  mail.
1044 1044  .RE
1045 1045  
1046 1046  .sp
1047 1047  .ne 2
1048 1048  .na
1049 1049  \fB\fB!\fR\fR
1050 1050  .ad
1051 1051  .RS 19n
1052 1052  The process number of the last background command invoked or the most recent
1053 1053  job put in the background with the \fBbg\fR built-in command.
1054 1054  .RE
1055 1055  
1056 1056  .sp
1057 1057  .ne 2
1058 1058  .na
1059 1059  \fB\fB\&.sh.command\fR\fR
1060 1060  .ad
1061 1061  .RS 19n
1062 1062  When processing a \fBDEBUG\fR trap, this variable contains the current command
1063 1063  line that is about to run.
1064 1064  .RE
1065 1065  
1066 1066  .sp
1067 1067  .ne 2
1068 1068  .na
1069 1069  \fB\fB\&.sh.edchar\fR\fR
1070 1070  .ad
1071 1071  .RS 19n
1072 1072  This variable contains the value of the keyboard character (or sequence of
1073 1073  characters if the first character is an ESC, \fBASCII 033\fR) that has been
1074 1074  entered when processing a \fBKEYBD\fR trap. If the value is changed as part of
1075 1075  the trap action, then the new value replaces the key (or key sequence) that
1076 1076  caused the trap. See the \fBKey Bindings\fR section of this manual page.
1077 1077  .RE
1078 1078  
1079 1079  .sp
1080 1080  .ne 2
1081 1081  .na
1082 1082  \fB\fB\&.sh.edcol\fR\fR
1083 1083  .ad
1084 1084  .RS 19n
1085 1085  The character position of the cursor at the time of the most recent \fBKEYBD\fR
1086 1086  trap.
1087 1087  .RE
1088 1088  
1089 1089  .sp
1090 1090  .ne 2
1091 1091  .na
1092 1092  \fB\fB\&.sh.edmode\fR\fR
1093 1093  .ad
1094 1094  .RS 19n
1095 1095  The value is set to ESC when processing a \fBKEYBD\fR trap while in \fBvi\fR
1096 1096  insert mode. Otherwise, \fB\&.sh.edmode\fR is null when processing a
1097 1097  \fBKEYBD\fR trap. See the \fBvi Editing Mode\fR section of this manual page.
1098 1098  .RE
1099 1099  
1100 1100  .sp
1101 1101  .ne 2
1102 1102  .na
1103 1103  \fB\fB\&.sh.edtext\fR\fR
1104 1104  .ad
1105 1105  .RS 19n
1106 1106  The characters in the input buffer at the time of the most recent \fBKEYBD\fR
1107 1107  trap. The value is null when not processing a \fBKEYBD\fR trap.
1108 1108  .RE
1109 1109  
1110 1110  .sp
1111 1111  .ne 2
1112 1112  .na
1113 1113  \fB\fB\&.sh.file\fR\fR
1114 1114  .ad
1115 1115  .RS 19n
1116 1116  The pathname of the file than contains the current command.
1117 1117  .RE
1118 1118  
1119 1119  .sp
1120 1120  .ne 2
1121 1121  .na
1122 1122  \fB\fB\&.sh.fun\fR\fR
1123 1123  .ad
1124 1124  .RS 19n
1125 1125  The name of the current function that is being executed.
1126 1126  .RE
1127 1127  
1128 1128  .sp
1129 1129  .ne 2
1130 1130  .na
1131 1131  \fB\fB\&.sh.match\fR\fR
1132 1132  .ad
1133 1133  .RS 19n
1134 1134  An indexed array which stores the most recent match and sub-pattern matches
1135 1135  after conditional pattern matches that match and after variables expansions
1136 1136  using the operators \fB#\fR, \fB%\fR, or \fB/\fR. The \fB0\fRth element stores
1137 1137  the complete match and the \fIi\fRth element stores the \fIi\fRth sub-match.
1138 1138  The \fB\&.sh.match\fR variable is unset when the variable that has expanded is
1139 1139  assigned a new value.
1140 1140  .RE
1141 1141  
1142 1142  .sp
1143 1143  .ne 2
1144 1144  .na
1145 1145  \fB\fB\&.sh.name\fR\fR
1146 1146  .ad
1147 1147  .RS 19n
1148 1148  Set to the name of the variable at the time that a discipline function is
1149 1149  invoked.
1150 1150  .RE
1151 1151  
1152 1152  .sp
1153 1153  .ne 2
1154 1154  .na
1155 1155  \fB\fB\&.sh.subscript\fR\fR
1156 1156  .ad
1157 1157  .RS 19n
1158 1158  Set to the name subscript of the variable at the time that a discipline
1159 1159  function is invoked.
1160 1160  .RE
1161 1161  
1162 1162  .sp
1163 1163  .ne 2
1164 1164  .na
1165 1165  \fB\fB\&.sh.subshell\fR\fR
1166 1166  .ad
1167 1167  .RS 19n
1168 1168  The current depth for sub-shells and command substitution.
1169 1169  .RE
1170 1170  
1171 1171  .sp
1172 1172  .ne 2
1173 1173  .na
1174 1174  \fB\fB\&.sh.value\fR\fR
1175 1175  .ad
1176 1176  .RS 19n
1177 1177  Set to the value of the variable at the time that the set or append discipline
1178 1178  function is invoked.
1179 1179  .RE
1180 1180  
1181 1181  .sp
1182 1182  .ne 2
1183 1183  .na
1184 1184  \fB\fB\&.sh.version\fR\fR
1185 1185  .ad
1186 1186  .RS 19n
1187 1187  Set to a value that identifies the version of this shell.
1188 1188  .RE
1189 1189  
1190 1190  .sp
1191 1191  .ne 2
1192 1192  .na
1193 1193  \fB\fBLINENO\fR\fR
1194 1194  .ad
1195 1195  .RS 19n
1196 1196  The current line number within the script or function being executed.
1197 1197  .RE
1198 1198  
1199 1199  .sp
1200 1200  .ne 2
1201 1201  .na
1202 1202  \fB\fBOLDPWD\fR\fR
1203 1203  .ad
1204 1204  .RS 19n
1205 1205  The previous working directory set by the \fBcd\fR command.
1206 1206  .RE
1207 1207  
1208 1208  .sp
1209 1209  .ne 2
1210 1210  .na
1211 1211  \fB\fBOPTARG\fR\fR
1212 1212  .ad
1213 1213  .RS 19n
1214 1214  The value of the last option argument processed by the \fBgetopts\fR built-in
1215 1215  command.
1216 1216  .RE
1217 1217  
1218 1218  .sp
1219 1219  .ne 2
1220 1220  .na
1221 1221  \fB\fBOPTIND\fR\fR
1222 1222  .ad
1223 1223  .RS 19n
1224 1224  The index of the last option argument processed by the \fBgetopts\fR built-in
1225 1225  command.
1226 1226  .RE
1227 1227  
1228 1228  .sp
1229 1229  .ne 2
1230 1230  .na
1231 1231  \fB\fBPPID\fR\fR
1232 1232  .ad
1233 1233  .RS 19n
1234 1234  The process number of the parent of the shell.
1235 1235  .RE
1236 1236  
1237 1237  .sp
1238 1238  .ne 2
1239 1239  .na
1240 1240  \fB\fBPWD\fR\fR
1241 1241  .ad
1242 1242  .RS 19n
1243 1243  The present working directory set by the \fBcd\fR command.
1244 1244  .RE
1245 1245  
1246 1246  .sp
1247 1247  .ne 2
1248 1248  .na
1249 1249  \fB\fBRANDOM\fR\fR
1250 1250  .ad
1251 1251  .RS 19n
1252 1252  Each time this variable is referenced, a random integer, uniformly distributed
1253 1253  between \fB0\fR and \fB32767\fR, is generated. The sequence of random numbers
1254 1254  can be initialized by assigning a numeric value to \fBRANDOM\fR.
1255 1255  .RE
1256 1256  
1257 1257  .sp
1258 1258  .ne 2
1259 1259  .na
1260 1260  \fB\fBREPLY\fR\fR
1261 1261  .ad
1262 1262  .RS 19n
1263 1263  This variable is set by the \fBselect\fR statement and by the \fBread\fR
1264 1264  built-in command when no arguments are supplied.
1265 1265  .RE
1266 1266  
1267 1267  .sp
1268 1268  .ne 2
1269 1269  .na
1270 1270  \fB\fBSECONDS\fR\fR
1271 1271  .ad
1272 1272  .RS 19n
1273 1273  Each time this variable is referenced, the number of seconds since shell
1274 1274  invocation is returned. If this variable is assigned a value, then the value
1275 1275  returned upon reference is the value that was assigned plus the number of
1276 1276  seconds since the assignment.
1277 1277  .RE
1278 1278  
1279 1279  .sp
1280 1280  .LP
1281 1281  The following variables are used by the shell:
1282 1282  .sp
1283 1283  .ne 2
1284 1284  .na
1285 1285  \fB\fBCDPATH\fR\fR
1286 1286  .ad
1287 1287  .RS 14n
1288 1288  Defines the search path for the \fBcd\fR command.
1289 1289  .RE
1290 1290  
1291 1291  .sp
1292 1292  .ne 2
1293 1293  .na
1294 1294  \fB\fBCOLUMNS\fR\fR
1295 1295  .ad
1296 1296  .RS 14n
1297 1297  Defines the width of the edit window for the shell edit modes and for printing
1298 1298  select lists.
1299 1299  .RE
1300 1300  
1301 1301  .sp
1302 1302  .ne 2
1303 1303  .na
1304 1304  \fB\fBEDITOR\fR\fR
1305 1305  .ad
1306 1306  .RS 14n
1307 1307  If the \fBVISUAL\fR variable is not set, the value of this variable is checked
1308 1308  for the patterns as described with \fBVISUAL\fR and the corresponding editing
1309 1309  option is turned on.
1310 1310  .sp
1311 1311  See the \fBset\fR command in the \fBSpecial Command\fR section of this manual
1312 1312  page.
1313 1313  .RE
1314 1314  
1315 1315  .sp
1316 1316  .ne 2
1317 1317  .na
1318 1318  \fB\fBENV\fR\fR
1319 1319  .ad
1320 1320  .RS 14n
1321 1321  Performs parameter expansion, command substitution, and arithmetic substitution
1322 1322  on the value to generate the pathname of the script that is executed when the
1323 1323  shell is invoked. This file is typically used for alias and function
1324 1324  definitions. The default value is \fB$HOME/.kshrc\fR.
1325 1325  .sp
1326 1326  See the \fBInvocation\fR section of this manual page.
1327 1327  .sp
1328 1328  \fBENV\fR is not set by the shell.
1329 1329  .RE
1330 1330  
1331 1331  .sp
1332 1332  .ne 2
1333 1333  .na
1334 1334  \fB\fBFCEDIT\fR\fR
1335 1335  .ad
1336 1336  .RS 14n
1337 1337  Obsolete name for the default editor name for the \fBhist\fR command.
1338 1338  \fBFCEDIT\fR is not used when \fBHISTEDIT\fR is set.
1339 1339  .sp
1340 1340  The shell specifies a default value to \fBFCEDIT\fR.
1341 1341  .RE
1342 1342  
1343 1343  .sp
1344 1344  .ne 2
1345 1345  .na
1346 1346  \fB\fBFIGNORE\fR\fR
1347 1347  .ad
1348 1348  .RS 14n
1349 1349  A pattern that defines the set of file names that is ignored when performing
1350 1350  file name matching.
1351 1351  .RE
1352 1352  
1353 1353  .sp
1354 1354  .ne 2
1355 1355  .na
1356 1356  \fB\fBFPATH\fR\fR
1357 1357  .ad
1358 1358  .RS 14n
1359 1359  The search path for function definitions. The directories in this path are
1360 1360  searched for a file with the same name as the function or command when a
1361 1361  function with the \fB-u\fR attribute is referenced and when a command is not
1362 1362  found. If an executable file with the name of that command is found, then it is
1363 1363  read and executed in the current environment. Unlike \fBPATH\fR, the current
1364 1364  directory must be represented explicitly by dot (\fB\&.\fR) rather than by
1365 1365  adjacent colon (\fB:\fR) characters or a beginning or ending colon (\fB:\fR).
1366 1366  .RE
1367 1367  
1368 1368  .sp
1369 1369  .ne 2
1370 1370  .na
1371 1371  \fB\fBHISTCMD\fR\fR
1372 1372  .ad
1373 1373  .RS 14n
1374 1374  The number of the current command in the history file.
1375 1375  .RE
1376 1376  
1377 1377  .sp
1378 1378  .ne 2
1379 1379  .na
1380 1380  \fB\fBHISTEDIT\fR\fR
1381 1381  .ad
1382 1382  .RS 14n
1383 1383  The name for the default editor name for the \fBhist\fR command.
1384 1384  .RE
1385 1385  
1386 1386  .sp
1387 1387  .ne 2
1388 1388  .na
1389 1389  \fB\fBHISTFILE\fR\fR
1390 1390  .ad
1391 1391  .RS 14n
1392 1392  If this variable is set when the shell is invoked, the value is the pathname of
1393 1393  the file that is used to store the command history. See the \fBCommand
1394 1394  Re-entry\fR section of this manual page.
1395 1395  .RE
1396 1396  
1397 1397  .sp
1398 1398  .ne 2
1399 1399  .na
1400 1400  \fB\fBHISTSIZE\fR\fR
1401 1401  .ad
1402 1402  .RS 14n
1403 1403  If this variable is set when the shell is invoked, then the number of
1404 1404  previously entered commands that are accessible by this shell is greater than
1405 1405  or equal to this number. The default is \fB512\fR.
1406 1406  .RE
1407 1407  
1408 1408  .sp
1409 1409  .ne 2
1410 1410  .na
1411 1411  \fB\fBHOME\fR\fR
1412 1412  .ad
1413 1413  .RS 14n
1414 1414  The default argument (home directory) for the \fBcd\fR command.
1415 1415  .sp
1416 1416  \fBHOME\fR is not set by the shell. \fBHOME\fR is set by \fBlogin\fR(1).
1417 1417  .RE
1418 1418  
1419 1419  .sp
1420 1420  .ne 2
1421 1421  .na
1422 1422  \fB\fBIFS\fR\fR
1423 1423  .ad
1424 1424  .RS 14n
1425 1425  Internal field separators, normally SPACE, TAB, and NEWLINE that are used to
1426 1426  separate the results of command substitution or parameter expansion and to
1427 1427  separate fields with the built-in command read. The first character of the
1428 1428  \fBIFS\fR variable is used to separate arguments for the \fB"$*"\fR
1429 1429  substitution. See the \fBQuoting\fR section of this manual page.
1430 1430  .sp
1431 1431  Each single occurrence of an \fBIFS\fR character in the string to be split,
1432 1432  that is not in the \fBissspace\fR character class, and any adjacent characters
1433 1433  in \fBIFS\fR that are in the \fBissspace\fR character class, delimit a field.
1434 1434  One or more characters in IFS that belong to the \fBissspace\fR character
1435 1435  class, delimit a field. In addition, if the same \fBissspace\fR character
1436 1436  appears consecutively inside \fBIFS\fR, this character is treated as if it were
1437 1437  not in the \fBissspace\fR class, so that if \fBIFS\fR consists of two tab
1438 1438  characters, then two adjacent tab characters delimit a null field.
1439 1439  .sp
1440 1440  The shell specifies a default value to \fBIFS\fR.
1441 1441  .RE
1442 1442  
1443 1443  .sp
1444 1444  .ne 2
1445 1445  .na
1446 1446  \fB\fBLANG\fR\fR
1447 1447  .ad
1448 1448  .RS 14n
1449 1449  This variable determines the locale category for any category not specifically
1450 1450  selected with a variable starting with \fBLC_\fR or \fBLANG\fR.
1451 1451  .RE
1452 1452  
1453 1453  .sp
1454 1454  .ne 2
1455 1455  .na
1456 1456  \fB\fBLC_ALL\fR\fR
1457 1457  .ad
1458 1458  .RS 14n
1459 1459  This variable overrides the value of the \fBLANG\fR variable and any other
1460 1460  \fBLC_\fR variable.
1461 1461  .RE
1462 1462  
1463 1463  .sp
1464 1464  .ne 2
1465 1465  .na
1466 1466  \fB\fBLC_COLLATE\fR\fR
1467 1467  .ad
1468 1468  .RS 14n
1469 1469  This variable determines the locale category for character collation
1470 1470  information.
1471 1471  .RE
1472 1472  
1473 1473  .sp
1474 1474  .ne 2
1475 1475  .na
1476 1476  \fB\fBLC_CTYPE\fR\fR
1477 1477  .ad
1478 1478  .RS 14n
1479 1479  This variable determines the locale category for character handling functions.
1480 1480  It determines the character classes for pattern matching. See the \fBFile Name
1481 1481  Generation\fR section of this manual page.
1482 1482  .RE
1483 1483  
1484 1484  .sp
1485 1485  .ne 2
1486 1486  .na
1487 1487  \fB\fBLC_NUMERIC\fR\fR
1488 1488  .ad
1489 1489  .RS 14n
1490 1490  This variable determines the locale category for the decimal point character.
1491 1491  .RE
1492 1492  
1493 1493  .sp
1494 1494  .ne 2
1495 1495  .na
1496 1496  \fB\fBLINES\fR\fR
1497 1497  .ad
1498 1498  .RS 14n
1499 1499  If this variable is set, the value is used to determine the column length for
1500 1500  printing select lists. Select lists prints vertically until about two-thirds of
1501 1501  \fBLINES\fR lines are filled.
1502 1502  .RE
1503 1503  
1504 1504  .sp
1505 1505  .ne 2
1506 1506  .na
1507 1507  \fB\fBMAIL\fR\fR
1508 1508  .ad
1509 1509  .RS 14n
1510 1510  If this variable is set to the name of a mail file \fBand\fR the \fBMAILPATH\fR
1511 1511  variable is not set, then the shell informs the user of arrival of mail in the
1512 1512  specified file.
1513 1513  .sp
1514 1514  \fBMAIL\fR is not set by the shell. On some systems, \fBMAIL\fR is set by
1515 1515  \fBlogin\fR(1).
1516 1516  .RE
1517 1517  
1518 1518  .sp
1519 1519  .ne 2
1520 1520  .na
1521 1521  \fB\fBMAILCHECK\fR\fR
1522 1522  .ad
1523 1523  .RS 14n
1524 1524  Specifies how often in seconds the shell checks for changes in the modification
1525 1525  time of any of the files specified by the \fBMAILPATH\fR or \fBMAIL\fR
1526 1526  variables. The default value is \fB600\fR seconds. When the time has elapsed
1527 1527  the shell checks before issuing the next prompt.
1528 1528  .sp
1529 1529  The shell specifies a default value to \fBMAILCHECK\fR.
1530 1530  .RE
1531 1531  
1532 1532  .sp
1533 1533  .ne 2
1534 1534  .na
1535 1535  \fB\fBMAILPATH\fR\fR
1536 1536  .ad
1537 1537  .RS 14n
1538 1538  A colon ( \fB:\fR ) separated list of file names. If this variable is set, then
1539 1539  the shell informs the user of any modifications to the specified files that
1540 1540  have occurred within the last \fBMAILCHECK\fR seconds. Each file name can be
1541 1541  followed by a \fB?\fR and a message that is printed. The message undergoes
1542 1542  parameter expansion, command substitution, and arithmetic substitution with the
1543 1543  variable \fB$_\fR defined as the name of the file that has changed. The default
1544 1544  message is \fByou have mail in $_\fR.
1545 1545  .RE
1546 1546  
1547 1547  .sp
1548 1548  .ne 2
1549 1549  .na
1550 1550  \fB\fBPATH\fR\fR
1551 1551  .ad
1552 1552  .RS 14n
1553 1553  The search path for commands. Except in \fB\&.profile\fR, users cannot change
1554 1554  \fBPATH\fR if executing under \fBrksh93\fR. See the \fBExecution\fR section of
1555 1555  this manual page.
1556 1556  .sp
1557 1557  The shell specifies a default value to \fBPATH\fR.
1558 1558  .RE
1559 1559  
1560 1560  .sp
1561 1561  .ne 2
1562 1562  .na
1563 1563  \fB\fBPS1\fR\fR
1564 1564  .ad
1565 1565  .RS 14n
1566 1566  The value of this variable is expanded for parameter expansion, command
1567 1567  substitution, and arithmetic substitution to define the primary prompt string
1568 1568  which by default is \fB$\fR. The character \fB!\fR in the primary prompt string
1569 1569  is replaced by the command number. Two successive occurrences of \fB!\fR
1570 1570  produces a single \fB!\fR when the prompt string is printed. See the \fBCommand
1571 1571  Re-entry\fR section of this manual page.
1572 1572  .sp
1573 1573  The shell specifies a default value to \fBPS1\fR.
1574 1574  .RE
1575 1575  
1576 1576  .sp
1577 1577  .ne 2
1578 1578  .na
1579 1579  \fB\fBPS2\fR\fR
1580 1580  .ad
1581 1581  .RS 14n
1582 1582  Secondary prompt string, by default, \fB>\fR.
1583 1583  .sp
1584 1584  The shell specifies a default value to \fBPS2\fR.
1585 1585  .RE
1586 1586  
1587 1587  .sp
1588 1588  .ne 2
1589 1589  .na
1590 1590  \fB\fBPS3\fR\fR
1591 1591  .ad
1592 1592  .RS 14n
1593 1593  Selection prompt string used within a select loop, by default \fB#?\fR.
1594 1594  .sp
1595 1595  The shell specifies a default value to \fBPS3\fR.
1596 1596  .RE
1597 1597  
1598 1598  .sp
1599 1599  .ne 2
1600 1600  .na
1601 1601  \fB\fBPS4\fR\fR
1602 1602  .ad
1603 1603  .RS 14n
1604 1604  The value of this variable is expanded for parameter evaluation, command
1605 1605  substitution, and arithmetic substitution and precedes each line of an
1606 1606  execution trace. By default, \fBPS4\fR is \fB+\fR. When \fBPS4\fR is unset, the
1607 1607  execution trace prompt is also \fB+\fR .
1608 1608  .sp
1609 1609  The shell specifies a default value to \fBPS4\fR.
1610 1610  .RE
1611 1611  
1612 1612  .sp
1613 1613  .ne 2
1614 1614  .na
1615 1615  \fB\fBSHELL\fR\fR
1616 1616  .ad
1617 1617  .RS 14n
1618 1618  The pathname of the shell is kept in the environment. At invocation, if the
1619 1619  basename of this variable is \fBrsh\fR, \fBrksh\fR, \fBrksh93\fR, or
1620 1620  \fBkrsh\fR, the shell becomes restricted.
1621 1621  .sp
1622 1622  \fBSHELL\fR is not set by the shell. On some systems, \fBSHELL\fR is set by
1623 1623  \fBlogin\fR(1).
1624 1624  .RE
1625 1625  
1626 1626  .sp
1627 1627  .ne 2
1628 1628  .na
1629 1629  \fB\fBTIMEFORMAT\fR\fR
1630 1630  .ad
1631 1631  .RS 14n
1632 1632  The value of this parameter is used as a format string specifying how the
1633 1633  timing information for pipelines prefixed with the \fBtime\fR reserved word
1634 1634  should be displayed. The \fB%\fR character introduces a format sequence that is
1635 1635  expanded to a time value or other information.
1636 1636  .sp
1637 1637  The format sequences and their meanings are as follows.
1638 1638  .sp
1639 1639  .ne 2
1640 1640  .na
1641 1641  \fB\fB%%\fR\fR
1642 1642  .ad
1643 1643  .sp .6
1644 1644  .RS 4n
1645 1645  A literal \fB%\fR.
1646 1646  .RE
1647 1647  
1648 1648  .sp
1649 1649  .ne 2
1650 1650  .na
1651 1651  \fB\fB%[\fIp\fR][l]R\fR\fR
1652 1652  .ad
1653 1653  .sp .6
1654 1654  .RS 4n
1655 1655  The elapsed time in seconds.
1656 1656  .RE
1657 1657  
1658 1658  .sp
1659 1659  .ne 2
1660 1660  .na
1661 1661  \fB\fB%[\fIp\fR][l]U\fR\fR
1662 1662  .ad
1663 1663  .sp .6
1664 1664  .RS 4n
1665 1665  The number of CPU seconds spent in user mode.
1666 1666  .RE
1667 1667  
1668 1668  .sp
1669 1669  .ne 2
1670 1670  .na
1671 1671  \fB\fB%[\fIp\fR][l]S\fR\fR
1672 1672  .ad
1673 1673  .sp .6
1674 1674  .RS 4n
1675 1675  The number of CPU seconds spent in system mode.
1676 1676  .RE
1677 1677  
1678 1678  .sp
1679 1679  .ne 2
1680 1680  .na
1681 1681  \fB\fB%P\fR\fR
1682 1682  .ad
1683 1683  .sp .6
1684 1684  .RS 4n
1685 1685  The CPU percentage, computed as \fB(U + S) / R\fR.
1686 1686  .RE
1687 1687  
1688 1688  The braces denote optional portions. The optional \fIp\fR is a digit specifying
1689 1689  the \fIprecision\fR, the number of fractional digits after a decimal point. A

1690 1690  value of \fB0\fR causes no decimal point or fraction to be output. At most
1691 1691  three places after the decimal point can be displayed. Values of \fIp\fR
1692 1692  greater than \fB3\fR are treated as \fB3\fR. If \fIp\fR is not specified, the
1693 1693  value \fB3\fR is used.
1694 1694  .sp
1695 1695  The optional \fBl\fR specifies a longer format, including hours if greater than
1696 1696  zero, minutes, and seconds of the form \fIHHhMMmSS.FFs\fR. The value of \fIp\fR
1697 1697  determines whether or not the fraction is included.
1698 1698  .sp
1699 1699  All other characters are output without change and a trailing NEWLINE is added.
1700      -If unset, the default value, \fB$'\nreal\t%2lR\nuser\t%2lU\nsys%2lS'\fR, is
     1700 +If unset, the default value, \fB$'\enreal\t%2lR\nuser\t%2lU\nsys%2lS'\fR, is
1701 1701  used. If the value is null, no timing information is displayed.
1702 1702  .RE
1703 1703  
1704 1704  .sp
1705 1705  .ne 2
1706 1706  .na
1707 1707  \fB\fBTMOUT\fR\fR
1708 1708  .ad
1709 1709  .RS 14n
1710 1710  If set to a value greater than zero, \fBTMOUT\fR is the default time-out value

1711 1711  for the \fBread\fR built-in command. The \fBselect\fR compound command
1712 1712  terminates after \fBTMOUT\fR seconds when input is from a terminal. Otherwise,
1713 1713  the shell terminates if a line is not entered within the prescribed number of
1714 1714  seconds while reading from a terminal. The shell can be compiled with a maximum
1715 1715  bound for this value which cannot be exceeded.
1716 1716  .sp
1717 1717  The shell specifies a default value to \fBTMOUT\fR.
1718 1718  .RE
1719 1719  
1720 1720  .sp
1721 1721  .ne 2
1722 1722  .na
1723 1723  \fB\fBVISUAL\fR\fR
1724 1724  .ad
1725 1725  .RS 14n
1726 1726  If the value of this variable matches the pattern \fB*[Vv][Ii]*\fR, then the
1727 1727  \fBvi\fR option is turned on. See \fBSpecial Commands\fR. If the value matches
1728 1728  the pattern \fB*gmacs*\fR , the \fBgmacs\fR option is turned on. If the value
1729 1729  matches the pattern \fB*macs*\fR, then the \fBemacs\fR option is turned on. The
1730 1730  value of \fBVISUAL\fR overrides the value of \fBEDITOR\fR.
1731 1731  .RE
1732 1732  
1733 1733  .SS "Field Splitting"
1734 1734  .sp
1735 1735  .LP
1736 1736  After parameter expansion and command substitution, the results of
1737 1737  substitutions are scanned for the field separator characters (those found in
1738 1738  \fBIFS\fR) and split into distinct fields where such characters are found.
1739 1739  Explicit null fields (\fB""\fR or \fB\&''\fR) are retained. Implicit null
1740 1740  fields, those resulting from parameters that have no values or command
1741 1741  substitutions with no output, are removed.
1742 1742  .sp
1743 1743  .LP
1744 1744  If the \fBbraceexpand\fR (\fB-B\fR) option is set, each of the fields resulting
1745 1745  from \fBIFS\fR are checked to see if they contain one or more of the brace
1746 1746  patterns. Valid brace patterns: \fB{*\fR,\fB*}\fR,
1747 1747  \fB{\fR\fIl1\fR\fB\&..\fR\fIl2\fR\fB}\fR ,
1748 1748  \fB{\fR\fIn1\fR\fB\&..\fR\fIn2\fR\fB}\fR,
1749 1749  \fB{\fR\fIn1\fR\fB\&..\fR\fIn2\fR\fB%\fR\fIfmt\fR\fB}
1750 1750  {\fR\fIn1\fR\fB\&..\fR\fIn2\fR \fB\&..\fR\fIn3\fR\fB}\fR, or
1751 1751  \fB{\fR\fIn1\fR\fB\&..\fR\fIn2\fR \fB\&..\fR\fIn3\fR\fB%\fR\fIfmt\fR\fB}\fR ,
1752 1752  where \fB*\fR represents any character, \fIl1\fR,\fIl2\fR are letters and
1753 1753  \fIn1\fR,\fIn2\fR,\fIn3\fR are signed numbers and \fIfmt\fR is a format
1754 1754  specified as used by \fBprintf\fR. In each case, fields are created by
1755 1755  prepending the characters before the \fB{\fR and appending the characters after
1756 1756  the } to each of the strings generated by the characters between the \fB{\fR
1757 1757  and \fB}\fR. The resulting fields are checked to see if they have any brace
1758 1758  patterns.
1759 1759  .sp
1760 1760  .LP
1761 1761  In the first form, a field is created for each string between \fB{\fR and
1762 1762  \fB,,\fR between \fB,\fR and \fB,,\fR and between , and \fB}\fR. The string
1763 1763  represented by \fB*\fR can contain embedded matching { and } without quoting.
1764 1764  Otherwise, each \fB{\fR and \fB}\fR with \fB*\fR must be quoted.
1765 1765  .sp
1766 1766  .LP
1767 1767  In the second form, \fIl1\fR and \fIl2\fR must both be either upper case or
1768 1768  both be lower case characters in the C locale. In this case a field is created
1769 1769  for each character from \fIl1\fR through \fIl2\fR.
1770 1770  .sp
1771 1771  .LP
1772 1772  In the remaining forms, a field is created for each number starting at
1773 1773  \fIn1\fR. This continues until it reaches \fIn2\fR and increments \fIn1\fR by
1774 1774  \fIn3\fR. The cases where \fIn3\fR is not specified behave as if \fIn3\fR were
1775 1775  1 if \fIn1\fR\fB<=\fR\fIn2\fR, and \fB-1\fR otherwise. In forms which specify
1776 1776  \fB%\fR\fIfmt\fR, any format flags, widths and precisions can be specified and
1777 1777  \fIfmt\fR can end in any of the specifiers \fBcdiouxX\fR. For example,
1778 1778  \fB{a,z}{1..5..3%02d}{b..c}x\fR expands to the 8 fields, \fBa01bx, a01cx,
1779 1779  a04bx, a04cx, z01bx, z01cx, z04bx,\fR and \fBz4cx\fR.
1780 1780  .SS "File Name Generation"
1781 1781  .sp
1782 1782  .LP
1783 1783  Following splitting, each field is scanned for the characters \fB*\fR, \fB?\fR,
1784 1784  \fB(\fR, and \fB[\fR, unless the \fB-f\fR option has been set. If one of these
1785 1785  characters appears, then the word is regarded as a pattern.
1786 1786  .sp
1787 1787  .LP
1788 1788  Each file name component that contains any pattern character is replaced with a
1789 1789  lexicographically sorted set of names that matches the pattern from that
1790 1790  directory. If no file name is found that matches the pattern, then that
1791 1791  component of the file name is left unchanged unless the pattern is prefixed
1792 1792  with \fB~(N)\fR in which case it is removed. If \fBFIGNORE\fR is set, then each
1793 1793  file name component that matches the pattern defined by the value of
1794 1794  \fBFIGNORE\fR is ignored when generating the matching file names. The names
1795 1795  \fB\&.\fR and \fB\&..\fR are also ignored. If \fBFIGNORE\fR is not set, the
1796 1796  character \fB\&.\fR at the start of each file name component is ignored unless
1797 1797  the first character of the pattern corresponding to this component is the
1798 1798  character \fB\&.\fR itself. For other uses of pattern matching the \fB/\fR and
1799 1799  \fB\&.\fR are not specially treated.
1800 1800  .sp
1801 1801  .ne 2
1802 1802  .na
1803 1803  \fB\fB*\fR\fR
1804 1804  .ad
1805 1805  .RS 11n
1806 1806  Match any string, including the null string. When used for file name expansion,
1807 1807  if the \fBglobstar\fR option is on, two adjacent \fB*\fRs by themselves match
1808 1808  all files and zero or more directories and subdirectories. If the two adjacent
1809 1809  \fB*\fRs are followed by a \fB/\fR, only directories and subdirectories match.
1810 1810  .RE
1811 1811  
1812 1812  .sp
1813 1813  .ne 2
1814 1814  .na
1815 1815  \fB\fB?\fR\fR
1816 1816  .ad
1817 1817  .RS 11n
1818 1818  Matches any single character.
1819 1819  .RE
1820 1820  
1821 1821  .sp
1822 1822  .ne 2
1823 1823  .na
1824 1824  \fB[\fB\&...\fR]\fR
1825 1825  .ad
1826 1826  .RS 11n
1827 1827  Match any one of the enclosed characters. A pair of characters separated by
1828 1828  \fB-\fR matches any character lexically between the pair, inclusive. If the
1829 1829  first character following the opening \fB[\fR is a \fB!\fR, any character not
1830 1830  enclosed is matched. A \fB-\fR can be included in the character set by putting
1831 1831  it as the first or last character. Within \fB[\fR and \fB]\fR, character
1832 1832  classes can be specified with the syntax \fB[:\fR\fIclass\fR\fB:]\fR where
1833 1833  \fIclass\fR is one of the following classes defined in the \fBANSI-C\fR
1834 1834  standard:
1835 1835  .sp
1836 1836  .in +2
1837 1837  .nf
1838 1838  \fIalnum alpha blank cntrl digit graph
1839 1839  lower print punct space upper
1840 1840  word xdigit\fR
1841 1841  .fi
1842 1842  .in -2
1843 1843  .sp
1844 1844  
1845 1845  \fIword\fR is equivalent to \fIalnum\fR plus the character \fB_\fR. Within
1846 1846  \fB[\fR and \fB]\fR, an equivalence class can be specified with the syntax
1847 1847  \fB[=\fR\fIc\fR\fB=]\fR which matches all characters with the same primary
1848 1848  collation weight (as defined by the current locale) as the character \fIc\fR.
1849 1849  Within \fB[\fR and \fB]\fR, [\fI\&.symbol.\fR] matches the collating symbol
1850 1850  \fIsymbol\fR.
1851 1851  .RE
1852 1852  
1853 1853  .sp
1854 1854  .LP
1855 1855  A \fIpattern-list\fR is a list of one or more patterns separated from each
1856 1856  other with an \fB&\fR or \fB|\fR. An \fB&\fR signifies that all patterns must
1857 1857  be matched whereas \fB|\fR requires that only one pattern be matched. Composite
1858 1858  patterns can be formed with one or more of the following sub-patterns:
1859 1859  .sp
1860 1860  .ne 2
1861 1861  .na
1862 1862  \fB\fB?(\fR\fIpattern-list\fR\fB)\fR\fR
1863 1863  .ad
1864 1864  .RS 22n
1865 1865  Optionally matches any one of the specified patterns.
1866 1866  .RE
1867 1867  
1868 1868  .sp
1869 1869  .ne 2
1870 1870  .na
1871 1871  \fB\fB*(\fR\fIpattern-list\fR\fB)\fR\fR
1872 1872  .ad
1873 1873  .RS 22n
1874 1874  Matches zero or more occurrences of the specified patterns.
1875 1875  .RE
1876 1876  
1877 1877  .sp
1878 1878  .ne 2
1879 1879  .na
1880 1880  \fB\fB+(\fR\fIpattern-list\fR\fB)\fR\fR
1881 1881  .ad
1882 1882  .RS 22n
1883 1883  Matches one or more occurrences of the specified patterns.
1884 1884  .RE
1885 1885  
1886 1886  .sp
1887 1887  .ne 2
1888 1888  .na
1889 1889  \fB\fB{\fR\fIn\fR\fB(\fR\fIpattern-list\fR\fB)\fR\fR
1890 1890  .ad
1891 1891  .RS 22n
1892 1892  Matches \fIn\fR occurrences of the specified patterns.
1893 1893  .RE
1894 1894  
1895 1895  .sp
1896 1896  .ne 2
1897 1897  .na
1898 1898  \fB\fB{\fR\fIm\fR\fB,\fR\fIn\fR\fB(\fR\fIpattern-list\fR\fB)\fR\fR
1899 1899  .ad
1900 1900  .RS 22n
1901 1901  Matches from \fIm\fR to \fIn\fR occurrences of the specified patterns. If
1902 1902  \fIm\fR is omitted, \fB0\fR is used. If \fIn\fR is omitted at least \fIm\fR
1903 1903  occurrences are matched.
1904 1904  .RE
1905 1905  
1906 1906  .sp
1907 1907  .ne 2
1908 1908  .na
1909 1909  \fB\fB@(\fR\fIpattern-list\fR\fB)\fR\fR
1910 1910  .ad
1911 1911  .RS 22n
1912 1912  Matches exactly one of the specified patterns.
1913 1913  .RE
1914 1914  
1915 1915  .sp
1916 1916  .ne 2
1917 1917  .na
1918 1918  \fB\fB!(\fR\fIpattern-list\fR\fB)\fR\fR
1919 1919  .ad
1920 1920  .RS 22n
1921 1921  Matches anything except one of the specified patterns.
1922 1922  .RE
1923 1923  
1924 1924  .sp
1925 1925  .LP
1926 1926  By default, each pattern, or sub-pattern matches the longest string possible
1927 1927  consistent with generating the longest overall match. If more than one match is
1928 1928  possible, the one starting closest to the beginning of the string is chosen.
1929 1929  However, for each of the compound patterns a \fB-\fR can be inserted in front
1930 1930  of the \fB(\fR to cause the shortest match to the specified \fIpattern-list\fR
1931 1931  to be used.
1932 1932  .sp
1933 1933  .LP
1934 1934  When \fIpattern-list\fR is contained within parentheses, the backslash
1935 1935  character \fB\e\fR is treated specially even when inside a character class. All
1936 1936  \fBANSI-C\fR character escapes are recognized and match the specified
1937 1937  character. In addition the following escape sequences are recognized:
1938 1938  .sp
1939 1939  .ne 2
1940 1940  .na
1941 1941  \fB\fB\ed\fR\fR
1942 1942  .ad
1943 1943  .RS 7n
1944 1944  Matches any character in the digit class.
1945 1945  .RE
1946 1946  
1947 1947  .sp
1948 1948  .ne 2
1949 1949  .na
1950 1950  \fB\fB\eD\fR\fR
1951 1951  .ad
1952 1952  .RS 7n
1953 1953  Matches any character not in the digit class.
1954 1954  .RE
1955 1955  
1956 1956  .sp
1957 1957  .ne 2
1958 1958  .na
1959 1959  \fB\fB\es\fR\fR
1960 1960  .ad
1961 1961  .RS 7n
1962 1962  Matches any character in the space class.
1963 1963  .RE
1964 1964  
1965 1965  .sp
1966 1966  .ne 2
1967 1967  .na
1968 1968  \fB\fB\eS\fR\fR
1969 1969  .ad
1970 1970  .RS 7n
1971 1971  Matches any character not in the space class.
1972 1972  .RE
1973 1973  
1974 1974  .sp
1975 1975  .ne 2
1976 1976  .na
1977 1977  \fB\fB\ew\fR\fR
1978 1978  .ad
1979 1979  .RS 7n
1980 1980  Matches any character in the word class.
1981 1981  .RE
1982 1982  
1983 1983  .sp
1984 1984  .ne 2
1985 1985  .na
1986 1986  \fB\fB\eW\fR\fR
1987 1987  .ad
1988 1988  .RS 7n
1989 1989  Matches any character not in the word class.
1990 1990  .RE
1991 1991  
1992 1992  .sp
1993 1993  .LP
1994 1994  A pattern of the form \fB%(\fR\fIpattern-pairs\fR\fB)\fR is a sub-pattern that
1995 1995  can be used to match nested character expressions. Each \fIpattern-pair\fR is a
1996 1996  two character sequence which cannot contain \fB&\fR or \fB|\fR. The first
1997 1997  \fIpattern-pair\fR specifies the starting and ending characters for the match.
1998 1998  Each subsequent \fIpattern-pair\fR represents the beginning and ending
1999 1999  characters of a nested group that is skipped over when counting starting and
2000 2000  ending character matches. The behavior is unspecified when the first character
2001 2001  of a \fIpattern-pair\fR is alphanumeric except for the following:
2002 2002  .sp
2003 2003  .ne 2
2004 2004  .na
2005 2005  \fB\fBD\fR\fR
2006 2006  .ad
2007 2007  .RS 5n
2008 2008  Causes the ending character to terminate the search for this pattern without
2009 2009  finding a match.
2010 2010  .RE
2011 2011  
2012 2012  .sp
2013 2013  .ne 2
2014 2014  .na
2015 2015  \fB\fBE\fR\fR
2016 2016  .ad
2017 2017  .RS 5n
2018 2018  Causes the ending character to be interpreted as an escape character.
2019 2019  .RE
2020 2020  
2021 2021  .sp
2022 2022  .ne 2
2023 2023  .na
2024 2024  \fB\fBL\fR\fR
2025 2025  .ad
2026 2026  .RS 5n
2027 2027  Causes the ending character to be interpreted as a quote character causing all
2028 2028  characters to be ignored when looking for a match.
2029 2029  .RE
2030 2030  
2031 2031  .sp
2032 2032  .ne 2
2033 2033  .na
2034 2034  \fB\fBQ\fR\fR
2035 2035  .ad
2036 2036  .RS 5n
2037 2037  Causes the ending character to be interpreted as a quote character causing all
2038 2038  characters other than any escape character to be ignored when looking for a
2039 2039  match.
2040 2040  .RE
2041 2041  
2042 2042  .sp
2043 2043  .LP
2044 2044  \fB%({}Q"E\e)\fR, matches characters starting at \fB{\fR until the matching
2045 2045  \fB}\fR is found not counting any \fB{\fR or \fB}\fR that is inside a double
2046 2046  quoted string or preceded by the escape character \fB\e\fR\&. Without the
2047 2047  \fB{}\fR this pattern matches any C language string.
2048 2048  .sp
2049 2049  .LP
2050 2050  Each sub-pattern in a composite pattern is numbered, starting at \fB1\fR, by
2051 2051  the location of the \fB(\fR within the pattern. The sequence \fB\e\fR\fIn\fR,
2052 2052  where \fIn\fR is a single digit and \fB\e\fR\fIn\fR comes after the \fIn\fRth.
2053 2053  sub-pattern, matches the same string as the sub-pattern itself.
2054 2054  .sp
2055 2055  .LP
2056 2056  A pattern can contain sub-patterns of the form
2057 2057  \fB~(\fR\fIoptions\fR\fB:\fR\fIpattern-list\fR\fB)\fR, where either
2058 2058  \fIoptions\fR or \fB:\fR\fIpattern-list\fR can be omitted. Unlike the other
2059 2059  compound patterns, these sub-patterns are not counted in the numbered
2060 2060  sub-patterns. If \fIoptions\fR is present, it can consist of one or more of the
2061 2061  following:
2062 2062  .sp
2063 2063  .ne 2
2064 2064  .na
2065 2065  \fB\fB+\fR\fR
2066 2066  .ad
2067 2067  .RS 5n
2068 2068  Enable the following options. This is the default.
2069 2069  .RE
2070 2070  
2071 2071  .sp
2072 2072  .ne 2
2073 2073  .na
2074 2074  \fB\fB-\fR\fR
2075 2075  .ad
2076 2076  .RS 5n
2077 2077  Disable the following options.
2078 2078  .RE
2079 2079  
2080 2080  .sp
2081 2081  .ne 2
2082 2082  .na
2083 2083  \fB\fBE\fR\fR
2084 2084  .ad
2085 2085  .RS 5n
2086 2086  The remainder of the pattern uses extended regular expression syntax like the
2087 2087  \fBegrep\fR(1) command.
2088 2088  .RE
2089 2089  
2090 2090  .sp
2091 2091  .ne 2
2092 2092  .na
2093 2093  \fB\fBF\fR\fR
2094 2094  .ad
2095 2095  .RS 5n
2096 2096  The remainder of the pattern uses \fBfgrep\fR(1) expression syntax.
2097 2097  .RE
2098 2098  
2099 2099  .sp
2100 2100  .ne 2
2101 2101  .na
2102 2102  \fB\fBg\fR\fR
2103 2103  .ad
2104 2104  .RS 5n
2105 2105  File the longest match (greedy).
2106 2106  .sp
2107 2107  This is the default.
2108 2108  .RE
2109 2109  
2110 2110  .sp
2111 2111  .ne 2
2112 2112  .na
2113 2113  \fB\fBG\fR\fR
2114 2114  .ad
2115 2115  .RS 5n
2116 2116  The remainder of the pattern uses basic regular expression syntax like the
2117 2117  \fBgrep\fR(1) command.
2118 2118  .RE
2119 2119  
2120 2120  .sp
2121 2121  .ne 2
2122 2122  .na
2123 2123  \fB\fBi\fR\fR
2124 2124  .ad
2125 2125  .RS 5n
2126 2126  Treat the match as case insensitive.
2127 2127  .RE
2128 2128  
2129 2129  .sp
2130 2130  .ne 2
2131 2131  .na
2132 2132  \fB\fBK\fR\fR
2133 2133  .ad
2134 2134  .RS 5n
2135 2135  The remainder of the pattern uses shell pattern syntax.
2136 2136  .sp
2137 2137  This is the default.
2138 2138  .RE
2139 2139  
2140 2140  .sp
2141 2141  .ne 2
2142 2142  .na
2143 2143  \fB\fBl\fR\fR
2144 2144  .ad
2145 2145  .RS 5n
2146 2146  Left anchor the pattern.
2147 2147  .sp
2148 2148  This is the default for \fBK\fR style patterns.
2149 2149  .RE
2150 2150  
2151 2151  .sp
2152 2152  .ne 2
2153 2153  .na
2154 2154  \fB\fBN\fR\fR
2155 2155  .ad
2156 2156  .RS 5n
2157 2157  This is ignored. However, when it is the first letter and is used with file
2158 2158  name generation, and no matches occur, the file pattern expands to the empty
2159 2159  string.
2160 2160  .RE
2161 2161  
2162 2162  .sp
2163 2163  .ne 2
2164 2164  .na
2165 2165  \fB\fBr\fR\fR
2166 2166  .ad
2167 2167  .RS 5n
2168 2168  Right anchor the pattern.
2169 2169  .sp
2170 2170  This is the default for \fBK\fR style patterns.
2171 2171  .RE
2172 2172  
2173 2173  .sp
2174 2174  .LP
2175 2175  If both \fIoptions\fR and \fB:\fR\fIpattern-list\fR are specified, then the
2176 2176  options apply only to \fIpattern-list\fR. Otherwise, these options remain in
2177 2177  effect until they are disabled by a subsequent \fB~(...)\fR or at the end of
2178 2178  the sub-pattern containing \fB~(...)\fR.
2179 2179  .SS "Quoting"
2180 2180  .sp
2181 2181  .LP
2182 2182  Each of the metacharacters listed in the \fBDefinitions\fR has a special
2183 2183  meaning to the shell.
2184 2184  .sp
2185 2185  .ne 2
2186 2186  .na
2187 2187  \fB\fBg\fR\fR
2188 2188  .ad
2189 2189  .RS 5n
2190 2190  File the longest match (greedy). This is the default.
2191 2191  .RE
2192 2192  
2193 2193  .sp
2194 2194  .ne 2
2195 2195  .na
2196 2196  \fB\fBi\fR\fR
2197 2197  .ad
2198 2198  .RS 5n
2199 2199  Treat the match as case insensitive.
2200 2200  .RE
2201 2201  
2202 2202  .sp
2203 2203  .LP
2204 2204  If both \fIoptions\fR and \fB:\fR\fIpattern-list\fR are specified, then the
2205 2205  options apply only to \fIpattern-list\fR. Otherwise, the options remain in
2206 2206  effect until they are disabled by a subsequent \fB~(...)\fR or at the end of
2207 2207  the sub-pattern containing \fB~(...)\fR.
2208 2208  .sp
2209 2209  .LP
2210 2210  Each of the metacharacters listed in the \fBDefinitions\fR section of this
2211 2211  manual page has a special meaning to the shell and causes termination of a word
2212 2212  unless quoted. A character can be quoted, that is, made to stand for itself, by
2213 2213  preceding it with a backslash (\fB\e\fR). The pair \fB\e\fRNEWLINE is removed.
2214 2214  All characters enclosed between a pair of single quote marks (\fB\&''\fR) that
2215 2215  is not preceded by a \fB$\fR are quoted. A single quote cannot appear within
2216 2216  the single quotes. A single quoted string preceded by an unquoted \fB$\fR is
2217 2217  processed as an \fBANSI-C\fR string except for the following:
2218 2218  .sp
2219 2219  .ne 2
2220 2220  .na
2221 2221  \fB\fB\e0\fR\fR
2222 2222  .ad
2223 2223  .RS 19n
2224 2224  Causes the remainder of the string to be ignored.
2225 2225  .RE
2226 2226  
2227 2227  .sp
2228 2228  .ne 2
2229 2229  .na
2230 2230  \fB\fB\ec\fR\fIx\fR\fR
2231 2231  .ad
2232 2232  .RS 19n
2233 2233  Expands to the character CTRL-x.
2234 2234  .RE
2235 2235  
2236 2236  .sp
2237 2237  .ne 2
2238 2238  .na
2239 2239  \fB\fB\eC\fR[\fB\&.\fR\fIname\fR\fB\&.\fR]\fR
2240 2240  .ad
2241 2241  .RS 19n
2242 2242  Expands to the collating element \fIname\fR.
2243 2243  .RE
2244 2244  
2245 2245  .sp
2246 2246  .ne 2
2247 2247  .na
2248 2248  \fB\fB\ee\fR\fR
2249 2249  .ad
2250 2250  .RS 19n
2251 2251  Equivalent to the escape character (\fBASCII\fR 033),
2252 2252  .RE
2253 2253  
2254 2254  .sp
2255 2255  .ne 2
2256 2256  .na
2257 2257  \fB\fB\eE\fR\fR
2258 2258  .ad
2259 2259  .RS 19n
2260 2260  Equivalent to the escape character (\fBASCII\fR 033),
2261 2261  .RE
2262 2262  
2263 2263  .sp
2264 2264  .LP
2265 2265  Inside double quote marks (\fB""\fR), parameter and command substitution occur
2266 2266  and \fB\e\fR quotes the characters \fB\e\fR, \fB`\fR, \fB"\fR, and \fB$\fR. A
2267 2267  \fB$\fR in front of a double quoted string is ignored in the \fBC\fR or
2268 2268  \fBPOSIX\fR locale, and might cause the string to be replaced by a locale
2269 2269  specific string otherwise. The meaning of \fB$*\fR and \fB$@\fR is identical
2270 2270  when not quoted or when used as a variable assignment value or as a file name.
2271 2271  However, when used as a command argument, \fB"$*"\fR is equivalent to
2272 2272  \fB"$1\fId\fR$2\fId\fR..."\fR, where \fId\fR is the first character of the IFS
2273 2273  variable, whereas \fB"$@"\fR is equivalent to \fB"$1" "$2" ....\fR Inside grave
2274 2274  quote marks (\fB``\fR), \fB\\fR quotes the characters \fB\e\fR, \fB`\fR, and
2275 2275  \fB$\fR. If the grave quotes occur within double quotes, then \fB\e\fR also
2276 2276  quotes the character \fB"\fR.
2277 2277  .sp
2278 2278  .LP
2279 2279  The special meaning of reserved words or aliases can be removed by quoting any
2280 2280  character of the reserved word. The recognition of function names or built-in
2281 2281  command names cannot be altered by quoting them.
2282 2282  .SS "Arithmetic Evaluation"
2283 2283  .sp
2284 2284  .LP
2285 2285  The shell performs arithmetic evaluation for arithmetic substitution, to
2286 2286  evaluate an arithmetic command, to evaluate an indexed array subscript, and to
2287 2287  evaluate arguments to the built-in commands \fBshift\fR and \fBlet\fR.
2288 2288  Arithmetic evaluation is also performed on argument operands of the built-in
2289 2289  command printf that correspond to numeric format specifiers in the format
2290 2290  operand. See \fBprintf\fR(1). Evaluations are performed using double precision
2291 2291  floating point arithmetic or long double precision floating point for systems
2292 2292  that provide this data type. Floating point constants follow the \fBANSI-C\fR
2293 2293  programming language floating point conventions. Integer constants follow the
2294 2294  \fBANSI-C\fR programming language integer constant conventions although only
2295 2295  single byte character constants are recognized and character casts are not
2296 2296  recognized. Constants can be of the form \fB[\fR\fIbase#\fR\fB]\fR\fIn\fR where
2297 2297  \fIbase\fR is a decimal number between two and sixty-four representing the
2298 2298  arithmetic base and \fIn\fR is a number in that base. The digits greater than
2299 2299  \fB9\fR are represented by the lower case letters, the upper case letters,
2300 2300  \fB@\fR, and \fB_\fR respectively. For bases less than or equal to \fB36\fR,
2301 2301  upper and lower case characters can be used interchangeably.
2302 2302  .sp
2303 2303  .LP
2304 2304  An arithmetic expression uses the same syntax, precedence, and associativity of
2305 2305  expression as the C language. All the C language operators that apply to
2306 2306  floating point quantities can be used. In addition, the operator \fB**\fR can
2307 2307  be used for exponentiation. It has higher precedence than multiplication and is
2308 2308  left associative. When the value of an arithmetic variable or subexpression can
2309 2309  be represented as a long integer, all C language integer arithmetic operations
2310 2310  can be performed. Variables can be referenced by name within an arithmetic
2311 2311  expression without using the parameter expansion syntax. When a variable is
2312 2312  referenced, its value is evaluated as an arithmetic expression.
2313 2313  .sp
2314 2314  .LP
2315 2315  Any of the following math library functions that are in the C math library can
2316 2316  be used within an arithmetic expression:
2317 2317  .sp
2318 2318  .in +2
2319 2319  .nf
2320 2320  abs acos acosh asin asinh atan atan2 atanh cbrt
2321 2321  copysign cos cosh erf erfc exp exp2 expm1 fabs
2322 2322  fdim finite floor fma fmax fmod hypot ilogb
2323 2323  int isinf isnan lgamma log log2 logb
2324 2324  nearbyint nextafter nexttoward pow remainder
2325 2325  rint round sin sinh sqrt tan tanh tgamma trunc
2326 2326  .fi
2327 2327  .in -2
2328 2328  .sp
2329 2329  
2330 2330  .sp
2331 2331  .LP
2332 2332  An internal representation of a \fIvariable\fR as a double precision floating
2333 2333  point can be specified with the \fB-E [\fR\fIn\fR\fB]\fR or \fB-F
2334 2334  [\fR\fIn\fR\fB]\fR option of the \fBtypeset\fR special built-in command. The
2335 2335  \fB-E\fR option causes the expansion of the value to be represented using
2336 2336  scientific notation when it is expanded. The optional option argument \fIn\fR
2337 2337  defines the number of significant figures. The \fB-F\fR option causes the
2338 2338  expansion to be represented as a floating decimal number when it is expanded.
2339 2339  The optional option argument \fIn\fR defines the number of places after the
2340 2340  decimal point in this case.
2341 2341  .sp
2342 2342  .LP
2343 2343  An internal integer representation of a \fIvariable\fR can be specified with
2344 2344  the \fB-i\fR \fB[\fR\fIn\fR\fB]\fR option of the \fBtypeset\fR special built-in
2345 2345  command. The optional option argument \fIn\fR specifies an arithmetic base to
2346 2346  be used when expanding the variable. If you do not specify an arithmetic base,
2347 2347  base 10 is used.
2348 2348  .sp
2349 2349  .LP
2350 2350  Arithmetic evaluation is performed on the value of each assignment to a
2351 2351  variable with the \fB-E\fR, \fB-F\fR, or \fB-i\fR option. Assigning a floating
2352 2352  point number to a variable whose type is an integer causes the fractional part
2353 2353  to be truncated.
2354 2354  .SS "Prompting"
2355 2355  .sp
2356 2356  .LP
2357 2357  When used interactively, the shell prompts with the value of \fBPS1\fR after
2358 2358  expanding it for parameter expansion, command substitution, and arithmetic
2359 2359  substitution, before reading a command. In addition, each single \fB!\fR in the
2360 2360  prompt is replaced by the command number. A \fB!!\fR is required to place
2361 2361  \fB!\fR in the prompt. If at any time a NEWLINE is typed and further input is
2362 2362  needed to complete a command, then the secondary prompt, that is, the value of
2363 2363  \fBPS2\fR, is issued.
2364 2364  .SS "Conditional Expressions"
2365 2365  .sp
2366 2366  .LP
2367 2367  A \fBconditional expression\fR is used with the \fB[[\fR compound command to
2368 2368  test attributes of files and to compare strings. Field splitting and file name
2369 2369  generation are not performed on the words between \fB[[\fR and \fB]]\fR.
2370 2370  .sp
2371 2371  .LP
2372 2372  Each expression can be constructed from one or more of the following unary or
2373 2373  binary expressions:
2374 2374  .sp
2375 2375  .ne 2
2376 2376  .na
2377 2377  \fB\fB-a\fR \fIfile\fR\fR
2378 2378  .ad
2379 2379  .RS 21n
2380 2380  True, if \fIfile\fR exists.
2381 2381  .sp
2382 2382  This option is the same as \fB-e\fR. This option is obsolete.
2383 2383  .RE
2384 2384  
2385 2385  .sp
2386 2386  .ne 2
2387 2387  .na
2388 2388  \fB\fB-b\fR \fIfile\fR\fR
2389 2389  .ad
2390 2390  .RS 21n
2391 2391  True, if \fIfile\fR exists and is a block special file.
2392 2392  .RE
2393 2393  
2394 2394  .sp
2395 2395  .ne 2
2396 2396  .na
2397 2397  \fB\fB-c\fR \fIfile\fR\fR
2398 2398  .ad
2399 2399  .RS 21n
2400 2400  True, if \fIfile\fR exists and is a character special file.
2401 2401  .RE
2402 2402  
2403 2403  .sp
2404 2404  .ne 2
2405 2405  .na
2406 2406  \fB\fB-d\fR \fIfile\fR\fR
2407 2407  .ad
2408 2408  .RS 21n
2409 2409  True, if \fIfile\fR exists and is a directory.
2410 2410  .RE
2411 2411  
2412 2412  .sp
2413 2413  .ne 2
2414 2414  .na
2415 2415  \fB\fB-e\fR \fIfile\fR\fR
2416 2416  .ad
2417 2417  .RS 21n
2418 2418  True, if \fIfile\fR exists.
2419 2419  .RE
2420 2420  
2421 2421  .sp
2422 2422  .ne 2
2423 2423  .na
2424 2424  \fB\fB-f\fR \fIfile\fR\fR
2425 2425  .ad
2426 2426  .RS 21n
2427 2427  True, if \fIfile\fR exists and is an ordinary file.
2428 2428  .RE
2429 2429  
2430 2430  .sp
2431 2431  .ne 2
2432 2432  .na
2433 2433  \fB\fB-g\fR \fIfile\fR\fR
2434 2434  .ad
2435 2435  .RS 21n
2436 2436  True, if \fIfile\fR exists and it has its \fBsetgid\fR bit set.
2437 2437  .RE
2438 2438  
2439 2439  .sp
2440 2440  .ne 2
2441 2441  .na
2442 2442  \fB\fB-G\fR \fIfile\fR\fR
2443 2443  .ad
2444 2444  .RS 21n
2445 2445  True, if \fIfile\fR exists and its group matches the effective group id of this
2446 2446  process.
2447 2447  .RE
2448 2448  
2449 2449  .sp
2450 2450  .ne 2
2451 2451  .na
2452 2452  \fB\fB-h\fR \fIfile\fR\fR
2453 2453  .ad
2454 2454  .RS 21n
2455 2455  True, if \fIfile\fR exists and is a symbolic link.
2456 2456  .RE
2457 2457  
2458 2458  .sp
2459 2459  .ne 2
2460 2460  .na
2461 2461  \fB\fB-k\fR \fIfile\fR\fR
2462 2462  .ad
2463 2463  .RS 21n
2464 2464  True, if \fIfile\fR exists and it has its sticky bit set.
2465 2465  .RE
2466 2466  
2467 2467  .sp
2468 2468  .ne 2
2469 2469  .na
2470 2470  \fB\fB-L\fR \fIfile\fR\fR
2471 2471  .ad
2472 2472  .RS 21n
2473 2473  True, if \fIfile\fR exists and is a symbolic link.
2474 2474  .RE
2475 2475  
2476 2476  .sp
2477 2477  .ne 2
2478 2478  .na
2479 2479  \fB\fB-n\fR \fIstring\fR\fR
2480 2480  .ad
2481 2481  .RS 21n
2482 2482  True, if length of \fIstring\fR is \fBnon-zero\fR.
2483 2483  .RE
2484 2484  
2485 2485  .sp
2486 2486  .ne 2
2487 2487  .na
2488 2488  \fB\fB-N\fR \fIfile\fR\fR
2489 2489  .ad
2490 2490  .RS 21n
2491 2491  True, if \fIfile\fR exists and the modification time is greater than the last
2492 2492  access time.
2493 2493  .RE
2494 2494  
2495 2495  .sp
2496 2496  .ne 2
2497 2497  .na
2498 2498  \fB\fB-o\fR \fIoption\fR\fR
2499 2499  .ad
2500 2500  .RS 21n
2501 2501  True, if option named \fIoption\fR is on.
2502 2502  .RE
2503 2503  
2504 2504  .sp
2505 2505  .ne 2
2506 2506  .na
2507 2507  \fB\fB-o\fR \fI?option\fR\fR
2508 2508  .ad
2509 2509  .RS 21n
2510 2510  True, if option named \fIoption\fR is a valid option name.
2511 2511  .RE
2512 2512  
2513 2513  .sp
2514 2514  .ne 2
2515 2515  .na
2516 2516  \fB\fB-O\fR \fIfile\fR\fR
2517 2517  .ad
2518 2518  .RS 21n
2519 2519  True, if \fIfile\fR exists and is owned by the effective user id of this
2520 2520  process.
2521 2521  .RE
2522 2522  
2523 2523  .sp
2524 2524  .ne 2
2525 2525  .na
2526 2526  \fB\fB-p\fR \fIfile\fR\fR
2527 2527  .ad
2528 2528  .RS 21n
2529 2529  True, if \fIfile\fR exists and is a \fBFIFO\fR special file or a pipe.
2530 2530  .RE
2531 2531  
2532 2532  .sp
2533 2533  .ne 2
2534 2534  .na
2535 2535  \fB\fB-r\fR \fIfile\fR\fR
2536 2536  .ad
2537 2537  .RS 21n
2538 2538  True, if \fIfile\fR exists and is readable by current process.
2539 2539  .RE
2540 2540  
2541 2541  .sp
2542 2542  .ne 2
2543 2543  .na
2544 2544  \fB\fB-s\fR \fIfile\fR\fR
2545 2545  .ad
2546 2546  .RS 21n
2547 2547  True, if \fIfile\fR exists and has size greater than zero.
2548 2548  .RE
2549 2549  
2550 2550  .sp
2551 2551  .ne 2
2552 2552  .na
2553 2553  \fB\fB-S\fR \fIfile\fR\fR
2554 2554  .ad
2555 2555  .RS 21n
2556 2556  True, if \fIfile\fR exists and is a socket.
2557 2557  .RE
2558 2558  
2559 2559  .sp
2560 2560  .ne 2
2561 2561  .na
2562 2562  \fB\fB-t\fR \fIfildes\fR\fR
2563 2563  .ad
2564 2564  .RS 21n
2565 2565  True, if file descriptor number \fIfildes\fR is open and associated with a
2566 2566  terminal device.
2567 2567  .RE
2568 2568  
2569 2569  .sp
2570 2570  .ne 2
2571 2571  .na
2572 2572  \fB\fB-u\fR \fIfile\fR\fR
2573 2573  .ad
2574 2574  .RS 21n
2575 2575  True, if \fIfile\fR exists and it has its \fBsetuid\fR bit set.
2576 2576  .RE
2577 2577  
2578 2578  .sp
2579 2579  .ne 2
2580 2580  .na
2581 2581  \fB\fB-w\fR \fIfile\fR\fR
2582 2582  .ad
2583 2583  .RS 21n
2584 2584  True, if \fIfile\fR exists and is writable by current process.
2585 2585  .RE
2586 2586  
2587 2587  .sp
2588 2588  .ne 2
2589 2589  .na
2590 2590  \fB\fB-x\fR \fIfile\fR\fR
2591 2591  .ad
2592 2592  .RS 21n
2593 2593  True, if \fIfile\fR exists and is executable by current process. If \fIfile\fR
2594 2594  exists and is a directory, then true if the current process has permission to
2595 2595  search in the directory.
2596 2596  .RE
2597 2597  
2598 2598  .sp
2599 2599  .ne 2
2600 2600  .na
2601 2601  \fB\fB-z\fR \fIstring\fR\fR
2602 2602  .ad
2603 2603  .RS 21n
2604 2604  True, if length of \fIstring\fR is zero.
2605 2605  .RE
2606 2606  
2607 2607  .sp
2608 2608  .ne 2
2609 2609  .na
2610 2610  \fB\fIfile1\fR \fB-ef\fR \fIfile2\fR\fR
2611 2611  .ad
2612 2612  .RS 21n
2613 2613  True, if \fIfile1\fR and \fIfile2\fR exist and refer to the same file.
2614 2614  .RE
2615 2615  
2616 2616  .sp
2617 2617  .ne 2
2618 2618  .na
2619 2619  \fB\fIfile1\fR \fB-nt\fR \fIfile2\fR\fR
2620 2620  .ad
2621 2621  .RS 21n
2622 2622  True, if \fIfile1\fR exists and \fIfile2\fR does not, or \fIfile1\fR is newer
2623 2623  than \fIfile2\fR.
2624 2624  .RE
2625 2625  
2626 2626  .sp
2627 2627  .ne 2
2628 2628  .na
2629 2629  \fB\fIfile1\fR \fB-ot\fR \fIfile2\fR\fR
2630 2630  .ad
2631 2631  .RS 21n
2632 2632  True, if \fIfile2\fR exists and \fIfile1\fR does not, or \fIfile1\fR is older
2633 2633  than \fIfile2\fR.
2634 2634  .RE
2635 2635  
2636 2636  .sp
2637 2637  .ne 2
2638 2638  .na
2639 2639  \fB\fIstring\fR\fR
2640 2640  .ad
2641 2641  .RS 21n
2642 2642  True, if \fIstring\fR is not null.
2643 2643  .RE
2644 2644  
2645 2645  .sp
2646 2646  .ne 2
2647 2647  .na
2648 2648  \fB\fIstring\fR \fB==\fR \fIpattern\fR\fR
2649 2649  .ad
2650 2650  .RS 21n
2651 2651  True, if \fIstring\fR matches \fIpattern\fR. Any part of \fIpattern\fR can be
2652 2652  quoted to cause it to be matched as a string. With a successful match to
2653 2653  \fIpattern\fR, the \fB\&.sh.match\fR array variable contains the match and
2654 2654  sub-pattern matches.
2655 2655  .RE
2656 2656  
2657 2657  .sp
2658 2658  .ne 2
2659 2659  .na
2660 2660  \fB\fIstring\fR \fB=\fR \fIpattern\fR\fR
2661 2661  .ad
2662 2662  .RS 21n
2663 2663  Same as \fB==\fR, but is obsolete.
2664 2664  .RE
2665 2665  
2666 2666  .sp
2667 2667  .ne 2
2668 2668  .na
2669 2669  \fB\fIstring\fR \fB!=\fR \fIpattern\fR\fR
2670 2670  .ad
2671 2671  .RS 21n
2672 2672  True, if \fIstring\fR does not match \fIpattern\fR. When the \fIstring\fR
2673 2673  matches the \fIpattern\fR the \fB\&.sh.match\fR array variable contains the
2674 2674  match and sub-pattern matches.
2675 2675  .RE
2676 2676  
2677 2677  .sp
2678 2678  .ne 2
2679 2679  .na
2680 2680  \fB\fIstring\fR \fB=~\fR \fIere\fR\fR
2681 2681  .ad
2682 2682  .RS 21n
2683 2683  True if \fIstring\fR matches the pattern \fB~(E)\fR\fIere\fR where \fIere\fR is
2684 2684  an extended regular expression.
2685 2685  .RE
2686 2686  
2687 2687  .sp
2688 2688  .ne 2
2689 2689  .na
2690 2690  \fB\fIstring1\fR \fB<\fR \fIstring2\fR\fR
2691 2691  .ad
2692 2692  .RS 21n
2693 2693  True, if \fIstring1\fR comes before \fIstring2\fR based on \fBASCII\fR value of
2694 2694  their characters.
2695 2695  .RE
2696 2696  
2697 2697  .sp
2698 2698  .ne 2
2699 2699  .na
2700 2700  \fB\fIstring1\fR \fB>\fR \fIstring2\fR\fR
2701 2701  .ad
2702 2702  .RS 21n
2703 2703  True, if \fIstring1\fR comes after \fIstring2\fR based on \fBASCII\fR value of
2704 2704  their characters.
2705 2705  .RE
2706 2706  
2707 2707  .sp
2708 2708  .LP
2709 2709  In each of the following expressions, if \fIfile\fR is of the form
2710 2710  \fB/dev/fd/\fR\fIn\fR, where \fIn\fR is an integer, the test is applied to the
2711 2711  open file whose descriptor number is \fIn\fR. The following obsolete arithmetic
2712 2712  comparisons are supported:
2713 2713  .sp
2714 2714  .ne 2
2715 2715  .na
2716 2716  \fB\fIexp1\fR \fB-eq\fR \fIexp2\fR\fR
2717 2717  .ad
2718 2718  .RS 17n
2719 2719  True, if \fIexp1\fR is equal to \fIexp2\fR.
2720 2720  .RE
2721 2721  
2722 2722  .sp
2723 2723  .ne 2
2724 2724  .na
2725 2725  \fB\fIexp1\fR \fB-ge\fR \fIexp2\fR\fR
2726 2726  .ad
2727 2727  .RS 17n
2728 2728  True, if \fIexp1\fR is greater than or equal to \fIexp2\fR.
2729 2729  .RE
2730 2730  
2731 2731  .sp
2732 2732  .ne 2
2733 2733  .na
2734 2734  \fB\fIexp1\fR \fB-gt\fR \fIexp2\fR\fR
2735 2735  .ad
2736 2736  .RS 17n
2737 2737  True, if \fIexp1\fR is greater than \fIexp2\fR.
2738 2738  .RE
2739 2739  
2740 2740  .sp
2741 2741  .ne 2
2742 2742  .na
2743 2743  \fB\fIexp1\fR \fB-le\fR \fIexp2\fR\fR
2744 2744  .ad
2745 2745  .RS 17n
2746 2746  True, if \fIexp1\fR is less than or equal to \fIexp2\fR.
2747 2747  .RE
2748 2748  
2749 2749  .sp
2750 2750  .ne 2
2751 2751  .na
2752 2752  \fB\fIexp1\fR \fB-lt\fR \fIexp2\fR\fR
2753 2753  .ad
2754 2754  .RS 17n
2755 2755  True, if \fIexp1\fR is less than \fIexp2\fR.
2756 2756  .RE
2757 2757  
2758 2758  .sp
2759 2759  .ne 2
2760 2760  .na
2761 2761  \fB\fIexp1\fR \fB-ne\fR \fIexp2\fR\fR
2762 2762  .ad
2763 2763  .RS 17n
2764 2764  True, if \fIexp1\fR is not equal to \fIexp2\fR.
2765 2765  .RE
2766 2766  
2767 2767  .sp
2768 2768  .LP
2769 2769  A compound expression can be constructed from these primitives by using any of
2770 2770  the following, listed in decreasing order of precedence:
2771 2771  .sp
2772 2772  .ne 2
2773 2773  .na
2774 2774  \fB\fB(\fR\fIexpression\fR\fB)\fR\fR
2775 2775  .ad
2776 2776  .RS 30n
2777 2777  True, if \fIexpression\fR is true. Used to group expressions.
2778 2778  .RE
2779 2779  
2780 2780  .sp
2781 2781  .ne 2
2782 2782  .na
2783 2783  \fB\fB!\fR \fIexpression\fR\fR
2784 2784  .ad
2785 2785  .RS 30n
2786 2786  True, if \fIexpression\fR is false.
2787 2787  .RE
2788 2788  
2789 2789  .sp
2790 2790  .ne 2
2791 2791  .na
2792 2792  \fB\fIexpression1\fR \fB&&\fR \fIexpression2\fR\fR
2793 2793  .ad
2794 2794  .RS 30n
2795 2795  True, if \fIexpression1\fR and \fIexpression2\fR are both true.
2796 2796  .RE
2797 2797  
2798 2798  .sp
2799 2799  .ne 2
2800 2800  .na
2801 2801  \fB\fIexpression1\fR \fB||\fR \fIexpression2\fR\fR
2802 2802  .ad
2803 2803  .RS 30n
2804 2804  True, if either \fIexpression1\fR or \fIexpression2\fR is true.
2805 2805  .RE
2806 2806  
2807 2807  .SS "Input and Output"
2808 2808  .sp
2809 2809  .LP
2810 2810  Before a command is executed, its input and output can be redirected using a
2811 2811  special notation interpreted by the shell. The following can appear anywhere in
2812 2812  a simple command or can precede or follow a command and are \fBnot\fR passed on
2813 2813  to the invoked command. Command substitution, parameter expansion, and
2814 2814  arithmetic substitution occur before \fIword\fR or \fIdigit\fR is used except
2815 2815  as noted in this section. File name generation occurs only if the shell is
2816 2816  interactive and the pattern matches a single file. Field splitting is not
2817 2817  performed.
2818 2818  .sp
2819 2819  .LP
2820 2820  In each of the following redirections, if \fIfile\fR is of the form
2821 2821  \fB/dev/sctp/\fR\fIhost\fR\fB/\fR\fIport\fR,
2822 2822  \fB/dev/tcp/\fR\fIhost\fR\fB/\fR\fIport\fR, or
2823 2823  \fB/dev/udp/\fR\fIhost\fR\fB/\fR\fIport\fR, where \fIhost\fR is a hostname or
2824 2824  host address, and \fIport\fR is a service specified by name or an integer port
2825 2825  number, then the redirection attempts to make a \fBtcp\fR, \fBsctp\fR or
2826 2826  \fBudp\fR connection to the corresponding socket.
2827 2827  .sp
2828 2828  .LP
2829 2829  No intervening space is allowed between the characters of redirection
2830 2830  operators.
2831 2831  .sp
2832 2832  .ne 2
2833 2833  .na
2834 2834  \fB\fB<\fR\fIword\fR\fR
2835 2835  .ad
2836 2836  .RS 14n
2837 2837  Use file \fIword\fR as standard input (file descriptor 0).
2838 2838  .RE
2839 2839  
2840 2840  .sp
2841 2841  .ne 2
2842 2842  .na
2843 2843  \fB\fB>\fR\fIword\fR\fR
2844 2844  .ad
2845 2845  .RS 14n
2846 2846  Use file \fIword\fR as standard output (file descriptor 1). If the file does
2847 2847  not exist then it is created. If the file exists, and the \fBnoclobber\fR
2848 2848  option is on, this causes an error. Otherwise, it is truncated to zero length.
2849 2849  .RE
2850 2850  
2851 2851  .sp
2852 2852  .ne 2
2853 2853  .na
2854 2854  \fB\fB>|\fR\fIword\fR\fR
2855 2855  .ad
2856 2856  .RS 14n
2857 2857  Same as \fB>\fR, except that it overrides the \fBnoclobber\fR option.
2858 2858  .RE
2859 2859  
2860 2860  .sp
2861 2861  .ne 2
2862 2862  .na
2863 2863  \fB\fB>>\fR\fIword\fR\fR
2864 2864  .ad
2865 2865  .RS 14n
2866 2866  Use file \fIword\fR as standard output. If the file exists, then output is
2867 2867  appended to it (by first seeking to the end-of-file). Otherwise, the file is
2868 2868  created.
2869 2869  .RE
2870 2870  
2871 2871  .sp
2872 2872  .ne 2
2873 2873  .na
2874 2874  \fB\fB<>\fR\fIword\fR\fR
2875 2875  .ad
2876 2876  .RS 14n
2877 2877  Open file \fIword\fR for reading and writing as standard input.
2878 2878  .RE
2879 2879  
2880 2880  .sp
2881 2881  .ne 2
2882 2882  .na
2883 2883  \fB\fB<<\fR\fB[-]\fR\fIword\fR\fR
2884 2884  .ad
2885 2885  .RS 14n
2886 2886  The shell input is read up to a line that is the same as \fIword\fR after any
2887 2887  quoting has been removed, or to an end-of-file. No parameter substitution,
2888 2888  command substitution, arithmetic substitution or file name generation is
2889 2889  performed on \fIword\fR. The resulting document, called a \fBhere-document\fR,
2890 2890  becomes the standard input. If any character of \fIword\fR is quoted, then no
2891 2891  interpretation is placed upon the characters of the document. Otherwise,
2892 2892  parameter expansion, command substitution, and arithmetic substitution occur,
2893 2893  \fB\e\fRNEWLINE is ignored, and \fB\e\fR must be used to quote the characters
2894 2894  \fB\e\fR, \fB$\fR, \fB`\fR\&. If \fB-\fR is appended to \fB<<\fR, then all
2895 2895  leading tabs are stripped from \fIword\fR and from the document. If \fB#\fR is
2896 2896  appended to \fB<<\fR, then leading SPACEs and TABs are stripped off the first
2897 2897  line of the document and up to an equivalent indentation is stripped from the
2898 2898  remaining lines and from \fIword\fR. A tab stop is assumed to occur at every 8
2899 2899  columns for the purposes of determining the indentation.
2900 2900  .RE
2901 2901  
2902 2902  .sp
2903 2903  .ne 2
2904 2904  .na
2905 2905  \fB\fB<<<\fR\fIword\fR\fR
2906 2906  .ad
2907 2907  .RS 14n
2908 2908  A short form of here document in which \fIword\fR becomes the contents of the
2909 2909  here-document after any parameter expansion, command substitution, and
2910 2910  arithmetic substitution occur.
2911 2911  .RE
2912 2912  
2913 2913  .sp
2914 2914  .ne 2
2915 2915  .na
2916 2916  \fB\fB<&\fR\fIdigit\fR\fR
2917 2917  .ad
2918 2918  .RS 14n
2919 2919  The standard input is duplicated from file descriptor \fIdigit\fR, and
2920 2920  similarly for the standard output using \fB>&\fR\fIdigit\fR. See \fBdup\fR(2).
2921 2921  .RE
2922 2922  
2923 2923  .sp
2924 2924  .ne 2
2925 2925  .na
2926 2926  \fB\fB<&\fR\fIdigit\fR\fB-\fR\fR
2927 2927  .ad
2928 2928  .RS 14n
2929 2929  The file descriptor specified by \fIdigit\fR is moved to standard input.
2930 2930  Similarly for the standard output using \fB>&\fR\fIdigit\fR\fB-\fR.
2931 2931  .RE
2932 2932  
2933 2933  .sp
2934 2934  .ne 2
2935 2935  .na
2936 2936  \fB\fB<&-\fR\fR
2937 2937  .ad
2938 2938  .RS 14n
2939 2939  The standard input is closed. Similarly for the standard output using
2940 2940  \fB>&-\fR.
2941 2941  .RE
2942 2942  
2943 2943  .sp
2944 2944  .ne 2
2945 2945  .na
2946 2946  \fB\fB<&p\fR\fR
2947 2947  .ad
2948 2948  .RS 14n
2949 2949  The input from the co-process is moved to standard input.
2950 2950  .RE
2951 2951  
2952 2952  .sp
2953 2953  .ne 2
2954 2954  .na
2955 2955  \fB\fB>&p\fR\fR
2956 2956  .ad
2957 2957  .RS 14n
2958 2958  The output to the co-process is moved to standard output.
2959 2959  .RE
2960 2960  
2961 2961  .sp
2962 2962  .ne 2
2963 2963  .na
2964 2964  \fB\fB<#((\fR\fIexpr\fR\fB))\fR\fR
2965 2965  .ad
2966 2966  .RS 14n
2967 2967  Evaluate arithmetic expression \fIexpr\fR and position file descriptor 0 to the
2968 2968  resulting value bytes from the start of the file. The variables \fBCUR\fR and
2969 2969  \fBEOF\fR evaluate to the current offset and end-of-file offset respectively
2970 2970  when evaluating \fIexpr\fR.
2971 2971  .RE
2972 2972  
2973 2973  .sp
2974 2974  .ne 2
2975 2975  .na
2976 2976  \fB\fB>#((\fR\fIexpr\fR\fB))\fR\fR
2977 2977  .ad
2978 2978  .RS 14n
2979 2979  The same as \fB<#\fR except applies to file descriptor 1.
2980 2980  .RE
2981 2981  
2982 2982  .sp
2983 2983  .ne 2
2984 2984  .na
2985 2985  \fB\fB<#\fR\fIpattern\fR\fR
2986 2986  .ad
2987 2987  .RS 14n
2988 2988  Seek forward to the beginning of the next line containing pattern.
2989 2989  .RE
2990 2990  
2991 2991  .sp
2992 2992  .ne 2
2993 2993  .na
2994 2994  \fB\fB<##\fR\fIpattern\fR\fR
2995 2995  .ad
2996 2996  .RS 14n
2997 2997  The same as \fB<#\fR, except that the portion of the file that is skipped is
2998 2998  copied to standard output.
2999 2999  .RE
3000 3000  
3001 3001  .sp
3002 3002  .LP
3003 3003  If one of the redirection operators is preceded by a digit, with no intervening
3004 3004  space, then the file descriptor number referred to is that specified by the
3005 3005  digit (instead of the default 0 or 1). If one of the redirection operators
3006 3006  other than \fB>&-\fR and the \fB>#\fR and \fB<#\fR forms, is preceded by
3007 3007  \fB{\fR\fIvarname\fR\fB}\fR with no intervening space, then a file descriptor
3008 3008  number \fB> 10\fR is selected by the shell and stored in the variable
3009 3009  \fIvarname\fR. If \fB>&-\fR or the any of the \fB>#\fR and \fB<#\fR forms is
3010 3010  preceded by \fB{\fR\fIvarname\fR\fB}\fR the value of \fIvarname\fR defines the
3011 3011  file descriptor to close or position. For example:
3012 3012  .sp
3013 3013  .in +2
3014 3014  .nf
3015 3015  \&... 2>&1
3016 3016  .fi
3017 3017  .in -2
3018 3018  .sp
3019 3019  
3020 3020  .sp
3021 3021  .LP
3022 3022  means file descriptor 2 is to be opened for writing as a duplicate of file
3023 3023  descriptor 1 and
3024 3024  .sp
3025 3025  .in +2
3026 3026  .nf
3027 3027  exec [\fIn\fR]<\fIfile\fR
3028 3028  .fi
3029 3029  .in -2
3030 3030  .sp
3031 3031  
3032 3032  .sp
3033 3033  .LP
3034 3034  means open \fIfile\fR for reading and store the file descriptor number in
3035 3035  variable \fIn\fR. The order in which redirections are specified is significant.
3036 3036  The shell evaluates each redirection in terms of the (\fIfile_descriptor\fR,
3037 3037  \fIfile\fR) association at the time of evaluation. For example:
3038 3038  .sp
3039 3039  .in +2
3040 3040  .nf
3041 3041  \&... 1>\fIfname\fR 2>&1
3042 3042  .fi
3043 3043  .in -2
3044 3044  .sp
3045 3045  
3046 3046  .sp
3047 3047  .LP
3048 3048  first associates file descriptor 1 with file \fIfname\fR. It then associates
3049 3049  file descriptor 2 with the file associated with file descriptor 1, that is,
3050 3050  \fIfname\fR. If the order of redirections were reversed, file descriptor 2
3051 3051  would be associated with the terminal (assuming file descriptor 1 had been) and
3052 3052  then file descriptor 1 would be associated with file \fIfname\fR. If a command
3053 3053  is followed by \fB&\fR and job control is not active, the default standard
3054 3054  input for the command is the empty file \fB/dev/null\fR. Otherwise, the
3055 3055  environment for the execution of a command contains the file descriptors of the
3056 3056  invoking shell as modified by input and output specifications.
3057 3057  .SS "Environment"
3058 3058  .sp
3059 3059  .LP
3060 3060  The \fIenvironment\fR is a list of name-value pairs that is passed to an
3061 3061  executed program in the same way as a normal argument list. See
3062 3062  \fBenviron\fR(5).
3063 3063  .sp
3064 3064  .LP
3065 3065  The names must be \fIidentifiers\fR and the values are character strings. The
3066 3066  shell interacts with the environment in several ways. On invocation, the shell
3067 3067  scans the environment and creates a variable for each name found, giving it the
3068 3068  corresponding value and attributes and marking it \fBexport\fR. Executed
3069 3069  commands inherit the environment. If the user modifies the values of these
3070 3070  variables or creates new ones, using the \fBexport\fR or \fBtypeset\fR \fB-x\fR
3071 3071  commands, they become part of the environment. The environment seen by any
3072 3072  executed command is thus composed of any name-value pairs originally inherited
3073 3073  by the shell, whose values can be modified by the current shell, plus any
3074 3074  additions which must be noted in \fBexport\fR or \fBtypeset\fR \fB-x\fR
3075 3075  commands. The environment for any simple-command or function can be augmented
3076 3076  by prefixing it with one or more variable assignments. A variable assignment
3077 3077  argument is a word of the form \fIidentifier\fR\fB=\fR\fIvalue\fR. Thus:
3078 3078  .sp
3079 3079  .in +2
3080 3080  .nf
3081 3081  TERM=450 cmd args
3082 3082  .fi
3083 3083  .in -2
3084 3084  .sp
3085 3085  
3086 3086  .sp
3087 3087  .LP
3088 3088  and
3089 3089  .sp
3090 3090  .in +2
3091 3091  .nf
3092 3092  (export TERM; TERM=450; cmd args)
3093 3093  .fi
3094 3094  .in -2
3095 3095  .sp
3096 3096  
3097 3097  .sp
3098 3098  .LP
3099 3099  are equivalent (as far as the execution of \fIcmd\fR is concerned except for
3100 3100  special built-in commands listed in the \fBBuilt-Ins\fR section, those that are
3101 3101  preceded with a dagger. If the obsolete \fB-k\fR option is set, all variable
3102 3102  assignment arguments are placed in the environment, even if they occur after
3103 3103  the command name.
3104 3104  .sp
3105 3105  .LP
3106 3106  The following example first prints \fBa=b c\fR and then \fBc\fR:
3107 3107  .sp
3108 3108  .in +2
3109 3109  .nf
3110 3110  echo a=b c
3111 3111  set -k
3112 3112  echo a=b c
3113 3113  .fi
3114 3114  .in -2
3115 3115  .sp
3116 3116  
3117 3117  .sp
3118 3118  .LP
3119 3119  This feature is intended for use with scripts written for early versions of the
3120 3120  shell and its use in new scripts is strongly discouraged.
3121 3121  .SS "Functions"
3122 3122  .sp
3123 3123  .LP
3124 3124  For historical reasons, there are two ways to define functions, the
3125 3125  \fBname()\fR syntax and the \fBfunction\fR \fBname\fR syntax. These are
3126 3126  described in the \fBCommands\fR section of this manual page.
3127 3127  .sp
3128 3128  .LP
3129 3129  Shell functions are read in and stored internally. Alias names are resolved
3130 3130  when the function is read. Functions are executed like commands with the
3131 3131  arguments passed as positional parameters. See the \fBExecution\fR section of
3132 3132  this manual page for details.
3133 3133  .sp
3134 3134  .LP
3135 3135  Functions defined by the \fBfunction\fR \fBname\fR syntax and called by name
3136 3136  execute in the same process as the caller and share all files and present
3137 3137  working directory with the caller. Traps caught by the caller are reset to
3138 3138  their default action inside the function. A trap condition that is not caught
3139 3139  or ignored by the function causes the function to terminate and the condition
3140 3140  to be passed on to the caller. A trap on \fBEXIT\fR set inside a function is
3141 3141  executed in the environment of the caller after the function completes.
3142 3142  Ordinarily, variables are shared between the calling program and the function.
3143 3143  However, the \fBtypeset\fR special built-in command used within a function
3144 3144  defines local variables whose scope includes the current function. They can be
3145 3145  passed to functions that they call in the variable assignment list that
3146 3146  precedes the call or as arguments passed as name references. Errors within
3147 3147  functions return control to the caller.
3148 3148  .sp
3149 3149  .LP
3150 3150  Functions defined with the \fBname()\fR syntax and functions defined with the
3151 3151  \fBfunction\fR \fBname\fR syntax that are invoked with the \fB\&.\fR special
3152 3152  built-in are executed in the caller's environment and share all variables and
3153 3153  traps with the caller. Errors within these function executions cause the script
3154 3154  that contains them to abort.
3155 3155  .sp
3156 3156  .LP
3157 3157  The special built-in command \fBreturn\fR is used to return from function
3158 3158  calls.
3159 3159  .sp
3160 3160  .LP
3161 3161  Function names can be listed with the \fB-f\fR or \fB+f\fR option of the
3162 3162  \fBtypeset\fR special built-in command. The text of functions, when available,
3163 3163  is also listed with \fB-f\fR. Functions can be undefined with the \fB-f\fR
3164 3164  option of the \fBunset\fR special built-in command.
3165 3165  .sp
3166 3166  .LP
3167 3167  Ordinarily, functions are unset when the shell executes a shell script.
3168 3168  Functions that need to be defined across separate invocations of the shell
3169 3169  should be placed in a directory and the \fBFPATH\fR variable should contain the
3170 3170  name of this directory. They can also be specified in the \fBENV\fR file.
3171 3171  .SS "Discipline Functions"
3172 3172  .sp
3173 3173  .LP
3174 3174  Each variable can have zero or more discipline functions associated with it.
3175 3175  The shell initially understands the discipline names \fBget\fR, \fBset\fR,
3176 3176  \fBappend\fR, and \fBunset\fR but on most systems others can be added at run
3177 3177  time via the C programming interface extension provided by the \fBbuiltin\fR
3178 3178  built-in utility. If the \fBget\fR discipline is defined for a variable, it is
3179 3179  invoked whenever the specified variable is referenced. If the variable
3180 3180  \fB\&.sh.value\fR is assigned a value inside the discipline function, the
3181 3181  referenced variable is evaluated to this value instead. If the \fBset\fR
3182 3182  discipline is defined for a variable, it is invoked whenever the specified
3183 3183  variable is assigned a value. If the \fBappend\fR discipline is defined for a
3184 3184  variable, it is invoked whenever a value is appended to the specified variable.
3185 3185  The variable \fB\&.sh.value\fR is specified the value of the variable before
3186 3186  invoking the discipline, and the variable is assigned the value of
3187 3187  \fB\&.sh.value\fR after the discipline completes. If .\fBsh.value\fR is
3188 3188  \fBunset\fR inside the discipline, then that value is unchanged. If the
3189 3189  \fBunset\fR discipline is defined for a variable, it is invoked whenever the
3190 3190  specified variable is unset. The variable is not unset unless it is unset
3191 3191  explicitly from within this discipline function.
3192 3192  .sp
3193 3193  .LP
3194 3194  The variable \fB\&.sh.name\fR contains the name of the variable for which the
3195 3195  discipline function is called, \fB\&.sh.subscript\fR is the subscript of the
3196 3196  variable, and \fB\&.sh.value\fR contains the value being assigned inside the
3197 3197  \fBset\fR discipline function. For the \fBset\fR discipline, changing
3198 3198  \fB\&.sh.value\fR changes the value that gets assigned.
3199 3199  .SS "Jobs"
3200 3200  .sp
3201 3201  .LP
3202 3202  If the monitor option of the \fBset\fR command is turned on, an interactive
3203 3203  shell associates a job with each pipeline. It keeps a table of current jobs,
3204 3204  printed by the \fBjobs\fR command, and assigns them small integer numbers. When
3205 3205  a job is started asynchronously with \fB&\fR, the shell prints a line which
3206 3206  looks like:
3207 3207  .sp
3208 3208  .in +2
3209 3209  .nf
3210 3210  [1] 1234
3211 3211  .fi
3212 3212  .in -2
3213 3213  .sp
3214 3214  
3215 3215  .sp
3216 3216  .LP
3217 3217  indicating that the job which was started asynchronously was job number 1 and
3218 3218  had one (top-level) process, whose process id was \fB1234\fR.
3219 3219  .sp
3220 3220  .LP
3221 3221  If you are running a job and wish to stop it, CTRL-z sends a \fBSTOP\fR signal
3222 3222  to the current job. The shell normally displays a message that the job has been
3223 3223  stopped, and displays another prompt. You can then manipulate the state of this
3224 3224  job, putting it in the background with the \fBbg\fR command, or run some other
3225 3225  commands and then eventually bring the job back into the foreground with the
3226 3226  foreground command \fBfg\fR. A CTRL-z takes effect immediately and is like an
3227 3227  interrupt in that pending output and unread input are discarded when it is
3228 3228  typed.
3229 3229  .sp
3230 3230  .LP
3231 3231  A job being run in the background stops if it tries to read from the terminal.
3232 3232  Background jobs are normally allowed to produce output, but this can be
3233 3233  disabled by giving the command \fBsttytostop\fR. If you set this \fBtty\fR
3234 3234  option, then background jobs stop when they try to produce output like they do
3235 3235  when they try to read input.
3236 3236  .sp
3237 3237  .LP
3238 3238  There are several ways to refer to jobs in the shell. A job can be referred to
3239 3239  by the process id of any process of the job or by one of the following:
3240 3240  .sp
3241 3241  .ne 2
3242 3242  .na
3243 3243  \fB\fB%\fR\fInumber\fR\fR
3244 3244  .ad
3245 3245  .RS 12n
3246 3246  The job with the specified number.
3247 3247  .RE
3248 3248  
3249 3249  .sp
3250 3250  .ne 2
3251 3251  .na
3252 3252  \fB\fB%\fR\fIstring\fR\fR
3253 3253  .ad
3254 3254  .RS 12n
3255 3255  Any job whose command line begins with \fIstring\fR.
3256 3256  .RE
3257 3257  
3258 3258  .sp
3259 3259  .ne 2
3260 3260  .na
3261 3261  \fB\fB%?\fR\fIstring\fR\fR
3262 3262  .ad
3263 3263  .RS 12n
3264 3264  Any job whose command line contains \fIstring\fR.
3265 3265  .RE
3266 3266  
3267 3267  .sp
3268 3268  .ne 2
3269 3269  .na
3270 3270  \fB\fB%%\fR\fR
3271 3271  .ad
3272 3272  .RS 12n
3273 3273  Current job.
3274 3274  .RE
3275 3275  
3276 3276  .sp
3277 3277  .ne 2
3278 3278  .na
3279 3279  \fB\fB%+\fR\fR
3280 3280  .ad
3281 3281  .RS 12n
3282 3282  Equivalent to \fB%%\fR.
3283 3283  .RE
3284 3284  
3285 3285  .sp
3286 3286  .ne 2
3287 3287  .na
3288 3288  \fB\fB%-\fR\fR
3289 3289  .ad
3290 3290  .RS 12n
3291 3291  Previous job.
3292 3292  .RE
3293 3293  
3294 3294  .sp
3295 3295  .LP
3296 3296  The shell learns immediately whenever a process changes state. It normally
3297 3297  informs you whenever a job becomes blocked so that no further progress is
3298 3298  possible, but only just before it prints a prompt. This is done so that it does
3299 3299  not otherwise disturb your work. The notify option of the \fBset\fR command
3300 3300  causes the shell to print these job change messages as soon as they occur.
3301 3301  .sp
3302 3302  .LP
3303 3303  When the \fBmonitor\fR option is on, each background job that completes
3304 3304  triggers any trap set for \fBCHLD\fR.
3305 3305  .sp
3306 3306  .LP
3307 3307  When you try to leave the shell while jobs are running or stopped, you are
3308 3308  warned that \fBYou have stopped(running) jobs.\fR You can use the \fBjobs\fR
3309 3309  command to see what they are. If you immediately try to exit again, the shell
3310 3310  does not warn you a second time, and the stopped jobs are terminated. When a
3311 3311  login shell receives a \fBHUP\fR signal, it sends a \fBHUP\fR signal to each
3312 3312  job that has not been disowned with the \fBdisown\fR built-in command.
3313 3313  .SS "Signals"
3314 3314  .sp
3315 3315  .LP
3316 3316  The \fBINT\fR and \fBQUIT\fR signals for an invoked command are ignored if the
3317 3317  command is followed by \fB&\fR and the \fBmonitor\fR option is not active.
3318 3318  Otherwise, signals have the values inherited by the shell from its parent. See
3319 3319  the \fBtrap\fR built-in command.
3320 3320  .SS "Execution"
3321 3321  .sp
3322 3322  .LP
3323 3323  Each time a command is read, the substitutions are carried out. If the command
3324 3324  name matches one of the ones in the \fBSpecial Built-in Commands\fR section of
3325 3325  this manual page, it is executed within the current shell process. Next, the
3326 3326  command name is checked to see if it matches a user defined function. If it
3327 3327  does, the positional parameters are saved and then reset to the arguments of
3328 3328  the function call. A function is also executed in the current shell process.
3329 3329  When the function completes or issues a return, the positional parameter list
3330 3330  is restored. For functions defined with the \fBfunction\fR \fBname\fR syntax,
3331 3331  any trap set on \fBEXIT\fR within the function is executed. The exit value of a
3332 3332  function is the value of the last command executed. If a command name is not a
3333 3333  special built-in command or a user defined function, but it is one of the
3334 3334  built-in commands, it is executed in the current shell process.
3335 3335  .sp
3336 3336  .LP
3337 3337  The shell variable \fBPATH\fR defines the search path for the directory
3338 3338  containing the command. Alternative directory names are separated by a colon
3339 3339  (\fB:\fR). The default path is \fB/bin:/usr/bin:\fR, specifying \fB/bin\fR,
3340 3340  \fB/usr/bin\fR, and the current directory in that order. The current directory
3341 3341  can be specified by two or more adjacent colons, or by a colon at the beginning
3342 3342  or end of the path list. If the command name contains a slash (\fB/\fR), the
3343 3343  search path is not used. Otherwise, each directory in the path is searched for
3344 3344  an executable file of the specified name that is not a directory. If found, and
3345 3345  if the shell determines that there is a built-in version of a command
3346 3346  corresponding to a specified pathname, this built-in is invoked in the current
3347 3347  process. If found, and this directory is also contained in the value of the
3348 3348  \fBFPATH\fR variable, then this file is loaded into the current shell
3349 3349  environment as if it were the argument to the . command except that only preset
3350 3350  aliases are expanded, and a function of the specified name is executed as
3351 3351  described in this manual page. If not found, and the file \fB\&.paths\fR is
3352 3352  found, and this file contains a line of the form \fBFPATH=\fR\fIpath\fR where
3353 3353  \fIpath\fR is an existing directory, and this directory contains a file of the
3354 3354  specified name, then this file is loaded into the current shell environment as
3355 3355  if it were the argument to the \fB\&. special\fR built-in command and a
3356 3356  function of the specified name is executed. Otherwise, if found, a process is
3357 3357  created and an attempt is made to execute the command using \fBexec\fR(2).
3358 3358  .sp
3359 3359  .LP
3360 3360  When an executable is found, the directory where it is found in is searched for
3361 3361  a file named \fB\&.paths\fR. If this file is found and it contains a line of
3362 3362  the form \fBBUILTIN_LIB=\fR\fIvalue\fR, the library named by \fIvalue\fR is
3363 3363  searched for as if it were an option argument to \fBbuiltin -f\fR, and if it
3364 3364  contains a built-in of the specified name this is executed instead of a command
3365 3365  by this name. Otherwise, if this file is found and it contains a line of the
3366 3366  form \fIname\fR\fB=\fR\fIvalue\fR in the first or second line, then the
3367 3367  environment variable \fIname\fR is modified by prepending the directory
3368 3368  specified by \fIvalue\fR to the directory list. If \fIvalue\fR is not an
3369 3369  absolute directory, then it specifies a directory relative to the directory
3370 3370  that the executable was found. If the environment variable \fIname\fR does not
3371 3371  already exist it is added to the environment list for the specified command.
3372 3372  .sp
3373 3373  .LP
3374 3374  If the file has execute permission but is not an \fBa.out\fR file, it is
3375 3375  assumed to be a file containing shell commands. A separate shell is spawned to
3376 3376  read it. All non-exported variables are removed in this case. If the shell
3377 3377  command file doesn't have read permission, and/or if the \fBsetuid\fR and
3378 3378  \fBsetgid\fR bits are set on the file, then the shell executes an agent whose
3379 3379  job it is to set up the permissions and execute the shell with the shell
3380 3380  command file passed down as an open file. A parenthesized command is executed
3381 3381  in a sub-shell without removing non-exported variables.
3382 3382  .SS "Command Re-entry"
3383 3383  .sp
3384 3384  .LP
3385 3385  The text of the last \fBHISTSIZE\fR (default 512) commands entered from a
3386 3386  terminal device is saved in a history file. The file \fB$HOME/.sh_history\fR is
3387 3387  used if the \fBHISTFILE\fR variable is not set or if the file it names is not
3388 3388  writable. A shell can access the commands of all interactive shells which use
3389 3389  the same named \fBHISTFILE\fR. The built-in command \fBhist\fR is used to list
3390 3390  or edit a portion of this file. The portion of the file to be edited or listed
3391 3391  can be selected by number or by giving the first character or characters of the
3392 3392  command. A single command or range of commands can be specified. If you do not
3393 3393  specify an editor program as an argument to \fBhist\fR then the value of the
3394 3394  variable \fBHISTEDIT\fR is used. If \fBHISTEDIT\fR is unset, the obsolete
3395 3395  variable \fBFCEDIT\fR is used. If \fBFCEDIT\fR is not defined, then
3396 3396  \fB/bin/ed\fR is used. The edited commands are printed and executed again upon
3397 3397  leaving the editor unless you quit without writing. The \fB-s\fR option (and in
3398 3398  obsolete versions, the editor name \fB-\fR) is used to skip the editing phase
3399 3399  and to re-execute the command. In this case a substitution parameter of the
3400 3400  form \fIold\fR\fB=\fR\fInew\fRcan be used to modify the command before
3401 3401  execution. For example, with the preset alias \fBr\fR, which is aliased to
3402 3402  \fB\&'hist -s'\fR, typing \fB`r bad=good c'\fR re-executes the most recent
3403 3403  command which starts with the letter \fBc\fR, replacing the first occurrence of
3404 3404  the string bad with the string good.
3405 3405  .SS "Inline Editing Options"
3406 3406  .sp
3407 3407  .LP
3408 3408  Normally, each command line entered from a terminal device is simply typed
3409 3409  followed by a NEWLINE (RETURN or LINE FEED). If either the \fBemacs\fR,
3410 3410  \fBgmacs\fR, or \fBvi\fR option is active, the user can edit the command line.
3411 3411  To be in either of these edit modes set the corresponding option. An editing
3412 3412  option is automatically selected each time the \fBVISUAL\fR or \fBEDITOR\fR
3413 3413  variable is assigned a value ending in either of these option names.
3414 3414  .sp
3415 3415  .LP
3416 3416  The editing features require that the user's terminal accept RETURN as carriage
3417 3417  return without line feed and that a SPACE must overwrite the current character
3418 3418  on the screen.
3419 3419  .sp
3420 3420  .LP
3421 3421  Unless the \fBmultiline\fR option is on, the editing modes implement a concept
3422 3422  where the user is looking through a window at the current line. The window
3423 3423  width is the value of \fBCOLUMNS\fR if it is defined, otherwise \fB80\fR. If
3424 3424  the window width is too small to display the prompt and leave at least 8
3425 3425  columns to enter input, the prompt is truncated from the left. If the line is
3426 3426  longer than the window width minus two, a mark is displayed at the end of the
3427 3427  window to notify the user. As the cursor moves and reaches the window
3428 3428  boundaries the window is centered about the cursor. The mark is a \fB>\fR
3429 3429  (\fB<, *\fR) if the line extends on the right , left, or both sides of the
3430 3430  window.
3431 3431  .sp
3432 3432  .LP
3433 3433  The search commands in each edit mode provide access to the history file. Only
3434 3434  strings are matched, not patterns, although a leading \fB^\fR in the string
3435 3435  restricts the match to begin at the first character in the line.
3436 3436  .sp
3437 3437  .LP
3438 3438  Each of the edit modes has an operation to list the files or commands that
3439 3439  match a partially entered word. When applied to the first word on the line, or
3440 3440  the first word after a \fB;\fR, \fB|\fR, \fB&\fR, or \fB(\fR, and the word does
3441 3441  not begin with \fB~\fR or contain a \fB/\fR, the list of aliases, functions,
3442 3442  and executable commands defined by the \fBPATH\fR variable that could match the
3443 3443  partial word is displayed. Otherwise, the list of files that match the
3444 3444  specified word is displayed. If the partially entered word does not contain any
3445 3445  file expansion characters, a \fB*\fR is appended before generating these lists.
3446 3446  After displaying the generated list, the input line is redrawn. These
3447 3447  operations are called command name listing and file name listing, respectively.
3448 3448  There are additional operations, referred to as command name completion and
3449 3449  file name completion, which compute the list of matching commands or files, but
3450 3450  instead of printing the list, replace the current word with a complete or
3451 3451  partial match. For file name completion, if the match is unique, a \fB/\fR is
3452 3452  appended if the file is a directory and a space is appended if the file is not
3453 3453  a directory. Otherwise, the longest common prefix for all the matching files
3454 3454  replaces the word. For command name completion, only the portion of the file
3455 3455  names after the last \fB/\fR are used to find the longest command prefix. If
3456 3456  only a single name matches this prefix, then the word is replaced with the
3457 3457  command name followed by a space. When using a \fBTAB\fR for completion that
3458 3458  does not yield a unique match, a subsequent TAB provides a numbered list of
3459 3459  matching alternatives. A specific selection can be made by entering the
3460 3460  selection number followed by a TAB.
3461 3461  .SS "Key Bindings"
3462 3462  .sp
3463 3463  .LP
3464 3464  The \fBKEYBD\fR trap can be used to intercept keys as they are typed and change
3465 3465  the characters that are actually seen by the shell. This trap is executed after
3466 3466  each character (or sequence of characters when the first character is ESC) is
3467 3467  entered while reading from a terminal.
3468 3468  .sp
3469 3469  .LP
3470 3470  The variable \fB\&.sh.edchar\fR contains the character or character sequence
3471 3471  which generated the trap. Changing the value of \fB\&.sh.edchar\fR in the trap
3472 3472  action causes the shell to behave as if the new value were entered from the
3473 3473  keyboard rather than the original value. The variable \fB\&.sh.edcol\fR is set
3474 3474  to the input column number of the cursor at the time of the input. The variable
3475 3475  \fB\&.sh.edmode\fR is set to \fBESC\fR when in \fBvi\fR insert mode and is null
3476 3476  otherwise. By prepending \fB${.sh.editmode}\fR to a value assigned to
3477 3477  \fB\&.sh.edchar\fR it causes the shell to change to control mode if it is not
3478 3478  already in this mode.
3479 3479  .sp
3480 3480  .LP
3481 3481  This trap is not invoked for characters entered as arguments to editing
3482 3482  directives, or while reading input for a character search.
3483 3483  .SS "\fBemacs\fR Editing Mode"
3484 3484  .sp
3485 3485  .LP
3486 3486  This mode is entered by enabling either the \fBemacs\fR or \fBgmacs\fR option.
3487 3487  The only difference between these two modes is the way they handle \fB^T\fR. To
3488 3488  edit, the user moves the cursor to the point needing correction and then
3489 3489  inserts or deletes characters or words as needed. All the editing commands are
3490 3490  control characters or escape sequences. The notation for control characters is
3491 3491  caret (\fB^\fR) followed by the character.
3492 3492  .sp
3493 3493  .LP
3494 3494  For example, \fB^F\fR is the notation for CTRL/F. This is entered by depressing
3495 3495  \fBf\fR while holding down the CTRL (control) key. The SHIFT key is not
3496 3496  depressed. (The notation \fB^?\fR indicates the DEL (delete) key.)
3497 3497  .sp
3498 3498  .LP
3499 3499  The notation for escape sequences is \fBM-\fR followed by a character. For
3500 3500  example, \fBM-f\fR (pronounced \fBMeta f\fR) is entered by depressing ESC
3501 3501  (\fBASCII 033\fR) followed by \fBf\fR. \fBM-F\fR is the notation for ESC
3502 3502  followed by \fBF\fR.
3503 3503  .sp
3504 3504  .LP
3505 3505  All edit commands operate from any place on the line, not just at the
3506 3506  beginning. The RETURN or the LINE FEED key is not entered after edit commands
3507 3507  except when noted.
3508 3508  .sp
3509 3509  .ne 2
3510 3510  .na
3511 3511  \fB\fB^F\fR\fR
3512 3512  .ad
3513 3513  .RS 13n
3514 3514  Move the cursor forward (right) one character.
3515 3515  .RE
3516 3516  
3517 3517  .sp
3518 3518  .ne 2
3519 3519  .na
3520 3520  \fB\fBM-[C\fR\fR
3521 3521  .ad
3522 3522  .RS 13n
3523 3523  Move the cursor forward (right) one character.
3524 3524  .RE
3525 3525  
3526 3526  .sp
3527 3527  .ne 2
3528 3528  .na
3529 3529  \fB\fBM-f\fR\fR
3530 3530  .ad
3531 3531  .RS 13n
3532 3532  Move the cursor forward one word. The \fBemacs\fR editor's idea of a word is a
3533 3533  string of characters consisting of only letters, digits and underscores.
3534 3534  .RE
3535 3535  
3536 3536  .sp
3537 3537  .ne 2
3538 3538  .na
3539 3539  \fB\fB^B\fR\fR
3540 3540  .ad
3541 3541  .RS 13n
3542 3542  Move the cursor backward (left) one character.
3543 3543  .RE
3544 3544  
3545 3545  .sp
3546 3546  .ne 2
3547 3547  .na
3548 3548  \fB\fBM-[D\fR\fR
3549 3549  .ad
3550 3550  .RS 13n
3551 3551  Move the cursor backward (left) one character.
3552 3552  .RE
3553 3553  
3554 3554  .sp
3555 3555  .ne 2
3556 3556  .na
3557 3557  \fB\fBM-b\fR\fR
3558 3558  .ad
3559 3559  .RS 13n
3560 3560  Move the cursor backward one word.
3561 3561  .RE
3562 3562  
3563 3563  .sp
3564 3564  .ne 2
3565 3565  .na
3566 3566  \fB\fB^A\fR\fR
3567 3567  .ad
3568 3568  .RS 13n
3569 3569  Move the cursor to the beginning of the line.
3570 3570  .RE
3571 3571  
3572 3572  .sp
3573 3573  .ne 2
3574 3574  .na
3575 3575  \fB\fBM-[H\fR\fR
3576 3576  .ad
3577 3577  .RS 13n
3578 3578  Move the cursor to the beginning of the line.
3579 3579  .RE
3580 3580  
3581 3581  .sp
3582 3582  .ne 2
3583 3583  .na
3584 3584  \fB\fB^E\fR\fR
3585 3585  .ad
3586 3586  .RS 13n
3587 3587  Move the cursor to the end of the line.
3588 3588  .RE
3589 3589  
3590 3590  .sp
3591 3591  .ne 2
3592 3592  .na
3593 3593  \fB\fBM-[Y\fR\fR
3594 3594  .ad
3595 3595  .RS 13n
3596 3596  Move the cursor to the end of line.
3597 3597  .RE
3598 3598  
3599 3599  .sp
3600 3600  .ne 2
3601 3601  .na
3602 3602  \fB\fB^]\fR\fIchar\fR\fR
3603 3603  .ad
3604 3604  .RS 13n
3605 3605  Move the cursor forward to the character \fIchar\fR on the current line.
3606 3606  .RE
3607 3607  
3608 3608  .sp
3609 3609  .ne 2
3610 3610  .na
3611 3611  \fB\fBM-^]\fR\fIchar\fR\fR
3612 3612  .ad
3613 3613  .RS 13n
3614 3614  Move the cursor backwards to the character \fIchar\fR on the current line.
3615 3615  .RE
3616 3616  
3617 3617  .sp
3618 3618  .ne 2
3619 3619  .na
3620 3620  \fB\fB^X^X\fR\fR
3621 3621  .ad
3622 3622  .RS 13n
3623 3623  Interchange the cursor and the mark.
3624 3624  .RE
3625 3625  
3626 3626  .sp
3627 3627  .ne 2
3628 3628  .na
3629 3629  \fB\fIerase\fR\fR
3630 3630  .ad
3631 3631  .RS 13n
3632 3632  Delete the previous character. The user-defined erase character is defined by
3633 3633  the \fBstty\fR(1) command, and is usually \fB^H\fR or \fB#\fR.
3634 3634  .RE
3635 3635  
3636 3636  .sp
3637 3637  .ne 2
3638 3638  .na
3639 3639  \fB\fIlnext\fR\fR
3640 3640  .ad
3641 3641  .RS 13n
3642 3642  Removes the next character's editing features. The user-defined literal next
3643 3643  character is defined by the \fBstty\fR(1) command, or is \fB^V\fR if not
3644 3644  defined.
3645 3645  .RE
3646 3646  
3647 3647  .sp
3648 3648  .ne 2
3649 3649  .na
3650 3650  \fB\fB^D\fR\fR
3651 3651  .ad
3652 3652  .RS 13n
3653 3653  Delete the current character.
3654 3654  .RE
3655 3655  
3656 3656  .sp
3657 3657  .ne 2
3658 3658  .na
3659 3659  \fB\fBM-d\fR\fR
3660 3660  .ad
3661 3661  .RS 13n
3662 3662  Delete the current word.
3663 3663  .RE
3664 3664  
3665 3665  .sp
3666 3666  .ne 2
3667 3667  .na
3668 3668  \fB\fBM-^H\fR\fR
3669 3669  .ad
3670 3670  .RS 13n
3671 3671  MetaBACKSPACE. Delete the previous word.
3672 3672  .RE
3673 3673  
3674 3674  .sp
3675 3675  .ne 2
3676 3676  .na
3677 3677  \fB\fBM-h\fR\fR
3678 3678  .ad
3679 3679  .RS 13n
3680 3680  Delete the previous word.
3681 3681  .RE
3682 3682  
3683 3683  .sp
3684 3684  .ne 2
3685 3685  .na
3686 3686  \fB\fBM-^?\fR\fR
3687 3687  .ad
3688 3688  .RS 13n
3689 3689  MetaDEL. Delete the previous word. If your interrupt character is \fB^?\fR
3690 3690  (DEL, the default), this command does not work.
3691 3691  .RE
3692 3692  
3693 3693  .sp
3694 3694  .ne 2
3695 3695  .na
3696 3696  \fB\fB^T\fR\fR
3697 3697  .ad
3698 3698  .RS 13n
3699 3699  Transpose the current character with the previous character, and advance the
3700 3700  cursor in \fBemacs\fR mode. Transpose two previous characters in \fBgmacs\fR
3701 3701  mode.
3702 3702  .RE
3703 3703  
3704 3704  .sp
3705 3705  .ne 2
3706 3706  .na
3707 3707  \fB\fB^C\fR\fR
3708 3708  .ad
3709 3709  .RS 13n
3710 3710  Capitalize the current character.
3711 3711  .RE
3712 3712  
3713 3713  .sp
3714 3714  .ne 2
3715 3715  .na
3716 3716  \fB\fBM-c\fR\fR
3717 3717  .ad
3718 3718  .RS 13n
3719 3719  Capitalize the current word.
3720 3720  .RE
3721 3721  
3722 3722  .sp
3723 3723  .ne 2
3724 3724  .na
3725 3725  \fB\fBM-l\fR\fR
3726 3726  .ad
3727 3727  .RS 13n
3728 3728  Change the current word to lower case.
3729 3729  .RE
3730 3730  
3731 3731  .sp
3732 3732  .ne 2
3733 3733  .na
3734 3734  \fB\fB^K\fR\fR
3735 3735  .ad
3736 3736  .RS 13n
3737 3737  Delete from the cursor to the end of the line. If preceded by a numerical
3738 3738  parameter whose value is less than the current cursor position, delete from
3739 3739  specified position up to the cursor. If preceded by a numerical parameter whose
3740 3740  value is greater than the current cursor position, then delete from cursor up
3741 3741  to specified cursor position.
3742 3742  .RE
3743 3743  
3744 3744  .sp
3745 3745  .ne 2
3746 3746  .na
3747 3747  \fB\fB^W\fR\fR
3748 3748  .ad
3749 3749  .RS 13n
3750 3750  Kill from the cursor to the mark.
3751 3751  .RE
3752 3752  
3753 3753  .sp
3754 3754  .ne 2
3755 3755  .na
3756 3756  \fB\fBM-p\fR\fR
3757 3757  .ad
3758 3758  .RS 13n
3759 3759  Push the region from the cursor to the mark on the stack.
3760 3760  .RE
3761 3761  
3762 3762  .sp
3763 3763  .ne 2
3764 3764  .na
3765 3765  \fB\fIkill\fR\fR
3766 3766  .ad
3767 3767  .RS 13n
3768 3768  Kill the entire current line. The user-defined kill character is defined by the
3769 3769  \fBstty\fR(1) command, usually a \fB^G\fR or \fB@\fR. If two kill characters
3770 3770  are entered in succession, all kill characters from then on cause a line feed.
3771 3771  This is useful when using paper terminals.
3772 3772  .RE
3773 3773  
3774 3774  .sp
3775 3775  .ne 2
3776 3776  .na
3777 3777  \fB\fB^Y\fR\fR
3778 3778  .ad
3779 3779  .RS 13n
3780 3780  Restore the last item removed from line. Yank the item back to the line.
3781 3781  .RE
3782 3782  
3783 3783  .sp
3784 3784  .ne 2
3785 3785  .na
3786 3786  \fB\fB^L\fR\fR
3787 3787  .ad
3788 3788  .RS 13n
3789 3789  Line feed and print the current line.
3790 3790  .RE
3791 3791  
3792 3792  .sp
3793 3793  .ne 2
3794 3794  .na
3795 3795  \fB\fBM-^L\fR\fR
3796 3796  .ad
3797 3797  .RS 13n
3798 3798  Clear the screen.
3799 3799  .RE
3800 3800  
3801 3801  .sp
3802 3802  .ne 2
3803 3803  .na
3804 3804  \fB\fB^@\fR\fR
3805 3805  .ad
3806 3806  .RS 13n
3807 3807  Null character. Set mark.
3808 3808  .RE
3809 3809  
3810 3810  .sp
3811 3811  .ne 2
3812 3812  .na
3813 3813  \fB\fBM-\fR\fIspace\fR\fR
3814 3814  .ad
3815 3815  .RS 13n
3816 3816  MetaSPACE. Set the mark.
3817 3817  .RE
3818 3818  
3819 3819  .sp
3820 3820  .ne 2
3821 3821  .na
3822 3822  \fB\fB^J\fR\fR
3823 3823  .ad
3824 3824  .RS 13n
3825 3825  New line. Execute the current line.
3826 3826  .RE
3827 3827  
3828 3828  .sp
3829 3829  .ne 2
3830 3830  .na
3831 3831  \fB\fB^M\fR\fR
3832 3832  .ad
3833 3833  .RS 13n
3834 3834  Return. Execute the current line.
3835 3835  .RE
3836 3836  
3837 3837  .sp
3838 3838  .ne 2
3839 3839  .na
3840 3840  \fB\fBEOF\fR\fR
3841 3841  .ad
3842 3842  .RS 13n
3843 3843  End-of-file character, normally \fB^D\fR, is processed as an \fBend-of-file\fR
3844 3844  only if the current line is null.
3845 3845  .RE
3846 3846  
3847 3847  .sp
3848 3848  .ne 2
3849 3849  .na
3850 3850  \fB\fB^P\fR\fR
3851 3851  .ad
3852 3852  .RS 13n
3853 3853  Fetch the previous command. Each time \fB^P\fR is entered the previous command
3854 3854  back in time is accessed. Moves back one line when it is not on the first line
3855 3855  of a multi-line command.
3856 3856  .RE
3857 3857  
3858 3858  .sp
3859 3859  .ne 2
3860 3860  .na
3861 3861  \fB\fBM-[A\fR\fR
3862 3862  .ad
3863 3863  .RS 13n
3864 3864  Equivalent to \fB^P\fR.
3865 3865  .RE
3866 3866  
3867 3867  .sp
3868 3868  .ne 2
3869 3869  .na
3870 3870  \fB\fBM-<\fR\fR
3871 3871  .ad
3872 3872  .RS 13n
3873 3873  Fetch the least recent (oldest) history line.
3874 3874  .RE
3875 3875  
3876 3876  .sp
3877 3877  .ne 2
3878 3878  .na
3879 3879  \fB\fBM->\fR\fR
3880 3880  .ad
3881 3881  .RS 13n
3882 3882  Fetch the most recent (youngest) history line.
3883 3883  .RE
3884 3884  
3885 3885  .sp
3886 3886  .ne 2
3887 3887  .na
3888 3888  \fB\fB^N\fR\fR
3889 3889  .ad
3890 3890  .RS 13n
3891 3891  Fetch the next command line. Each time \fB^N\fR is entered the next command
3892 3892  line forward in time is accessed.
3893 3893  .RE
3894 3894  
3895 3895  .sp
3896 3896  .ne 2
3897 3897  .na
3898 3898  \fB\fBM-[B\fR\fR
3899 3899  .ad
3900 3900  .RS 13n
3901 3901  Equivalent to \fB^N\fR.
3902 3902  .RE
3903 3903  
3904 3904  .sp
3905 3905  .ne 2
3906 3906  .na
3907 3907  \fB\fB^R\fR\fIstring\fR\fR
3908 3908  .ad
3909 3909  .RS 13n
3910 3910  Reverse search history for a previous command line containing \fIstring\fR. If
3911 3911  a parameter of zero is specified, the search is forward. \fIstring\fR is
3912 3912  terminated by a RETURN or NEWLINE. If string is preceded by a \fB^\fR, the
3913 3913  matched line must begin with \fIstring\fR. If \fIstring\fR is omitted, then the
3914 3914  next command line containing the most recent \fIstring\fR is accessed. In this
3915 3915  case a parameter of zero reverses the direction of the search.
3916 3916  .RE
3917 3917  
3918 3918  .sp
3919 3919  .ne 2
3920 3920  .na
3921 3921  \fB\fB^O\fR\fR
3922 3922  .ad
3923 3923  .RS 13n
3924 3924  Operate. Execute the current line and fetch the next line relative to current
3925 3925  line from the history file.
3926 3926  .RE
3927 3927  
3928 3928  .sp
3929 3929  .ne 2
3930 3930  .na
3931 3931  \fB\fBM-\fR\fIdigits\fR\fR
3932 3932  .ad
3933 3933  .RS 13n
3934 3934  Escape. Define numeric parameter. The digits are taken as a parameter to the
3935 3935  next command. The commands that accept a parameter are: \fB^F\fR, \fB^B\fR,
3936 3936  \fBERASE\fR, \fB^C\fR, \fB^D\fR, \fB^K\fR, \fB^R\fR, \fB^P\fR, \fB^N\fR,
3937 3937  \fB^]\fR, \fBM-.\fR, \fBM-\fR, \fBM-^]\fR, \fBM-_\fR, \fBM-=\fR, \fBM-b\fR,
3938 3938  \fBM-c\fR, \fBM-d\fR, \fBM-f\fR, \fBM-h\fR, \fBM-l\fR, and \fBM-^H\fR.
3939 3939  .RE
3940 3940  
3941 3941  .sp
3942 3942  .ne 2
3943 3943  .na
3944 3944  \fB\fBM-\fR\fIletter\fR\fR
3945 3945  .ad
3946 3946  .RS 13n
3947 3947  Soft-key. Search the alias list for an alias by the name \fIletter\fR. If an
3948 3948  alias of \fIletter\fR is defined, insert its value on the input queue.
3949 3949  \fIletter\fR must not be one of the metafunctions in this section.
3950 3950  .RE
3951 3951  
3952 3952  .sp
3953 3953  .ne 2
3954 3954  .na
3955 3955  \fB\fBM-[\fR\fIletter\fR\fR
3956 3956  .ad
3957 3957  .RS 13n
3958 3958  Soft key. Search the alias list for an alias by the name \fIletter\fR. If an
3959 3959  alias of this name is defined, insert its value on the input queue. This can be
3960 3960  used to program function keys on many terminals.
3961 3961  .RE
3962 3962  
3963 3963  .sp
3964 3964  .ne 2
3965 3965  .na
3966 3966  \fB\fBM-.\fR\fR
3967 3967  .ad
3968 3968  .RS 13n
3969 3969  The last word of the previous command is inserted on the line. If preceded by a
3970 3970  numeric parameter, the value of this parameter determines which word to insert
3971 3971  rather than the last word.
3972 3972  .RE
3973 3973  
3974 3974  .sp
3975 3975  .ne 2
3976 3976  .na
3977 3977  \fB\fBM-_\fR\fR
3978 3978  .ad
3979 3979  .RS 13n
3980 3980  Same as \fBM-.\fR.
3981 3981  .RE
3982 3982  
3983 3983  .sp
3984 3984  .ne 2
3985 3985  .na
3986 3986  \fB\fBM-*\fR\fR
3987 3987  .ad
3988 3988  .RS 13n
3989 3989  Attempt filename generation on the current word. As asterisk is appended if the
3990 3990  word does not match any file or contain any special pattern characters.
3991 3991  .RE
3992 3992  
3993 3993  .sp
3994 3994  .ne 2
3995 3995  .na
3996 3996  \fB\fBM-\fRESC\fR
3997 3997  .ad
3998 3998  .RS 13n
3999 3999  Command or file name completion as described in this manual page.
4000 4000  .RE
4001 4001  
4002 4002  .sp
4003 4003  .ne 2
4004 4004  .na
4005 4005  \fB\fB^I\fRTAB\fR
4006 4006  .ad
4007 4007  .RS 13n
4008 4008  Attempts command or file name completion as described in this manual page. If a
4009 4009  partial completion occurs, repeating this behaves as if \fBM-=\fR were entered.
4010 4010  If no match is found or entered after SPACE, a TAB is inserted.
4011 4011  .RE
4012 4012  
4013 4013  .sp
4014 4014  .ne 2
4015 4015  .na
4016 4016  \fB\fBM-=\fR\fR
4017 4017  .ad
4018 4018  .RS 13n
4019 4019  If not preceded by a numeric parameter, generates the list of matching commands
4020 4020  or file names as described in this manual page. Otherwise, the word under the
4021 4021  cursor is replaced by the item corresponding to the value of the numeric
4022 4022  parameter from the most recently generated command or file list. If the cursor
4023 4023  is not on a word, the word is inserted instead.
4024 4024  .RE
4025 4025  
4026 4026  .sp
4027 4027  .ne 2
4028 4028  .na
4029 4029  \fB\fB^U\fR\fR
4030 4030  .ad
4031 4031  .RS 13n
4032 4032  Multiply parameter of next command by \fB4\fR.
4033 4033  .RE
4034 4034  
4035 4035  .sp
4036 4036  .ne 2
4037 4037  .na
4038 4038  \fB\fB\e\fR\fR
4039 4039  .ad
4040 4040  .RS 13n
4041 4041  Escape the next character. Editing characters, the user's erase, kill and
4042 4042  interrupt (normally \fB^?\fR) characters can be entered in a command line or in
4043 4043  a search string if preceded by a \fB\e\fR\&. The \fB\e\fR removes the next
4044 4044  character's editing features, if any.
4045 4045  .RE
4046 4046  
4047 4047  .sp
4048 4048  .ne 2
4049 4049  .na
4050 4050  \fB\fBM-^V\fR\fR
4051 4051  .ad
4052 4052  .RS 13n
4053 4053  Display the version of the shell.
4054 4054  .RE
4055 4055  
4056 4056  .sp
4057 4057  .ne 2
4058 4058  .na
4059 4059  \fB\fBM-#\fR\fR
4060 4060  .ad
4061 4061  .RS 13n
4062 4062  If the line does not begin with a \fB#\fR, a \fB#\fR is inserted at the
4063 4063  beginning of the line and after each NEWLINE, and the line is entered. This
4064 4064  causes a comment to be inserted in the history file. If the line begins with a
4065 4065  \fB#\fR, the \fB#\fR is deleted and one \fB#\fR after each NEWLINE is also
4066 4066  deleted.
4067 4067  .RE
4068 4068  
4069 4069  .SS "\fBvi\fR Editing Mode"
4070 4070  .sp
4071 4071  .LP
4072 4072  There are two typing modes. Initially, when you enter a command you are in the
4073 4073  input mode. To edit, the user enters control mode by typing ESC (033) and moves
4074 4074  the cursor to the point needing correction and then inserts or deletes
4075 4075  characters or words as needed. Most control commands accept an optional repeat
4076 4076  \fIcount\fR prior to the command.
4077 4077  .sp
4078 4078  .LP
4079 4079  When in vi mode on most systems, canonical processing is initially enabled and
4080 4080  the command is echoed again if the speed is 1200 baud or greater and it
4081 4081  contains any control characters or less than one second has elapsed since the
4082 4082  prompt was printed. The ESC character terminates canonical processing for the
4083 4083  remainder of the command and the user can then modify the command line. This
4084 4084  scheme has the advantages of canonical processing with the type-ahead echoing
4085 4085  of raw mode.
4086 4086  .sp
4087 4087  .LP
4088 4088  If the option \fBviraw\fR is also set, the terminal is always have canonical
4089 4089  processing disabled. This mode is implicit for systems that do not support two
4090 4090  alternate end of line delimiters, and might be helpful for certain terminals.
4091 4091  .SS "Input Edit Commands"
4092 4092  .sp
4093 4093  .LP
4094 4094  By default the editor is in input mode.
4095 4095  .sp
4096 4096  .LP
4097 4097  The following input edit commands are supported:
4098 4098  .sp
4099 4099  .ne 2
4100 4100  .na
4101 4101  \fBERASE\fR
4102 4102  .ad
4103 4103  .RS 10n
4104 4104  User defined erase character as defined by the \fBstty\fR command, usually
4105 4105  \fB^H\fR or \fB#\fR. Delete previous character.
4106 4106  .RE
4107 4107  
4108 4108  .sp
4109 4109  .ne 2
4110 4110  .na
4111 4111  \fB\fB^W\fR\fR
4112 4112  .ad
4113 4113  .RS 10n
4114 4114  Delete the previous blank separated word. On some systems the \fBviraw\fR
4115 4115  option might be required for this to work.
4116 4116  .RE
4117 4117  
4118 4118  .sp
4119 4119  .ne 2
4120 4120  .na
4121 4121  \fBEOF\fR
4122 4122  .ad
4123 4123  .RS 10n
4124 4124  As the first character of the line causes the shell to terminate unless the
4125 4125  \fBignoreeof\fR option is set. Otherwise this character is ignored.
4126 4126  .RE
4127 4127  
4128 4128  .sp
4129 4129  .ne 2
4130 4130  .na
4131 4131  \fB\fIlnext\fR\fR
4132 4132  .ad
4133 4133  .RS 10n
4134 4134  User defined literal next character as defined by the \fBstty\fR(1) or \fB^V\fR
4135 4135  if not defined. Removes the next character's editing features, if any. On some
4136 4136  systems the \fBviraw\fR option might be required for this to work.
4137 4137  .RE
4138 4138  
4139 4139  .sp
4140 4140  .ne 2
4141 4141  .na
4142 4142  \fB\fB\e\fR\fR
4143 4143  .ad
4144 4144  .RS 10n
4145 4145  Escape the next ERASE or KILL character.
4146 4146  .RE
4147 4147  
4148 4148  .sp
4149 4149  .ne 2
4150 4150  .na
4151 4151  \fB\fB^I\fR TAB\fR
4152 4152  .ad
4153 4153  .RS 10n
4154 4154  Attempts command or file name completion as described in this manual page and
4155 4155  returns to input mode. If a partial completion occurs, repeating this behaves
4156 4156  as if \fB=\fR were entered from control mode. If no match is found or entered
4157 4157  after SPACE, a TAB is inserted.
4158 4158  .RE
4159 4159  
4160 4160  .SS "Motion Edit Commands"
4161 4161  .sp
4162 4162  .LP
4163 4163  The motion edit commands move the cursor.
4164 4164  .sp
4165 4165  .LP
4166 4166  The following motion edit commands are supported:
4167 4167  .sp
4168 4168  .ne 2
4169 4169  .na
4170 4170  \fB\fB[\fR\fIcount\fR\fB]l\fR\fR
4171 4171  .ad
4172 4172  .RS 13n
4173 4173  Move the cursor forward (right) one character.
4174 4174  .RE
4175 4175  
4176 4176  .sp
4177 4177  .ne 2
4178 4178  .na
4179 4179  \fB\fB[\fR\fIcount\fR\fB][C\fR\fR
4180 4180  .ad
4181 4181  .RS 13n
4182 4182  Move the cursor forward (right) one character.
4183 4183  .RE
4184 4184  
4185 4185  .sp
4186 4186  .ne 2
4187 4187  .na
4188 4188  \fB\fB[\fR\fIcount\fR\fB]w\fR\fR
4189 4189  .ad
4190 4190  .RS 13n
4191 4191  Move the cursor forward one alphanumeric word.
4192 4192  .RE
4193 4193  
4194 4194  .sp
4195 4195  .ne 2
4196 4196  .na
4197 4197  \fB\fB[\fR\fIcount\fR\fB]W\fR\fR
4198 4198  .ad
4199 4199  .RS 13n
4200 4200  Move the cursor to the beginning of the next word that follows a blank.
4201 4201  .RE
4202 4202  
4203 4203  .sp
4204 4204  .ne 2
4205 4205  .na
4206 4206  \fB\fB[\fR\fIcount\fR\fB]e\fR\fR
4207 4207  .ad
4208 4208  .RS 13n
4209 4209  Move the cursor to the end of the word.
4210 4210  .RE
4211 4211  
4212 4212  .sp
4213 4213  .ne 2
4214 4214  .na
4215 4215  \fB\fB[\fR\fIcount\fR\fB]E\fR\fR
4216 4216  .ad
4217 4217  .RS 13n
4218 4218  Move the cursor to the end of the current blank delimited word.
4219 4219  .RE
4220 4220  
4221 4221  .sp
4222 4222  .ne 2
4223 4223  .na
4224 4224  \fB\fB[\fR\fIcount\fR\fB]h\fR\fR
4225 4225  .ad
4226 4226  .RS 13n
4227 4227  Move the cursor backward (left) one character.
4228 4228  .RE
4229 4229  
4230 4230  .sp
4231 4231  .ne 2
4232 4232  .na
4233 4233  \fB\fB[\fR\fIcount\fR\fB][D\fR\fR
4234 4234  .ad
4235 4235  .RS 13n
4236 4236  Move the cursor backward (left) one character.
4237 4237  .RE
4238 4238  
4239 4239  .sp
4240 4240  .ne 2
4241 4241  .na
4242 4242  \fB\fB[\fR\fIcount\fR\fB]b\fR\fR
4243 4243  .ad
4244 4244  .RS 13n
4245 4245  Move the cursor backward one word.
4246 4246  .RE
4247 4247  
4248 4248  .sp
4249 4249  .ne 2
4250 4250  .na
4251 4251  \fB\fB[\fR\fIcount\fR\fB]B\fR\fR
4252 4252  .ad
4253 4253  .RS 13n
4254 4254  Move the cursor to the preceding blank separated word.
4255 4255  .RE
4256 4256  
4257 4257  .sp
4258 4258  .ne 2
4259 4259  .na
4260 4260  \fB\fB[\fR\fIcount\fR\fB]|\fR\fR
4261 4261  .ad
4262 4262  .RS 13n
4263 4263  Move the cursor to column \fIcount\fR.
4264 4264  .RE
4265 4265  
4266 4266  .sp
4267 4267  .ne 2
4268 4268  .na
4269 4269  \fB\fB[\fR\fIcount\fR\fB]f\fR\fIc\fR\fR
4270 4270  .ad
4271 4271  .RS 13n
4272 4272  Find the next character \fIc\fR in the current line.
4273 4273  .RE
4274 4274  
4275 4275  .sp
4276 4276  .ne 2
4277 4277  .na
4278 4278  \fB\fB[\fR\fIcount\fR\fB]F\fR\fIc\fR\fR
4279 4279  .ad
4280 4280  .RS 13n
4281 4281  Find the previous character \fIc\fR in the current line.
4282 4282  .RE
4283 4283  
4284 4284  .sp
4285 4285  .ne 2
4286 4286  .na
4287 4287  \fB\fB[\fR\fIcount\fR\fB]t\fR\fIC\fR\fR
4288 4288  .ad
4289 4289  .RS 13n
4290 4290  Equivalent to \fBf\fR followed by \fBh\fR.
4291 4291  .RE
4292 4292  
4293 4293  .sp
4294 4294  .ne 2
4295 4295  .na
4296 4296  \fB\fB[\fR\fIcount\fR\fB]T\fR\fIc\fR\fR
4297 4297  .ad
4298 4298  .RS 13n
4299 4299  Equivalent to \fBF\fR followed by \fBl\fR.
4300 4300  .RE
4301 4301  
4302 4302  .sp
4303 4303  .ne 2
4304 4304  .na
4305 4305  \fB\fB[\fR\fIcount\fR\fB];\fR\fR
4306 4306  .ad
4307 4307  .RS 13n
4308 4308  Repeat \fIcount\fR times the last single character find command: \fBf\fR,
4309 4309  \fBF\fR, \fBt,\fR or \fBT\fR.
4310 4310  .RE
4311 4311  
4312 4312  .sp
4313 4313  .ne 2
4314 4314  .na
4315 4315  \fB\fB[\fR\fIcount\fR\fB],\fR\fR
4316 4316  .ad
4317 4317  .RS 13n
4318 4318  Reverse the last single character find command \fIcount\fR times.
4319 4319  .RE
4320 4320  
4321 4321  .sp
4322 4322  .ne 2
4323 4323  .na
4324 4324  \fB\fB0\fR\fR
4325 4325  .ad
4326 4326  .RS 13n
4327 4327  Move the cursor to the start of line.
4328 4328  .RE
4329 4329  
4330 4330  .sp
4331 4331  .ne 2
4332 4332  .na
4333 4333  \fB\fB^\fR\fR
4334 4334  .ad
4335 4335  .RS 13n
4336 4336  Move the cursor to start of line.
4337 4337  .RE
4338 4338  
4339 4339  .sp
4340 4340  .ne 2
4341 4341  .na
4342 4342  \fB\fB[H\fR\fR
4343 4343  .ad
4344 4344  .RS 13n
4345 4345  Move the cursor to the first non-blank character in the line.
4346 4346  .RE
4347 4347  
4348 4348  .sp
4349 4349  .ne 2
4350 4350  .na
4351 4351  \fB\fB$\fR\fR
4352 4352  .ad
4353 4353  .RS 13n
4354 4354  Move the cursor to the end of the line.
4355 4355  .RE
4356 4356  
4357 4357  .sp
4358 4358  .ne 2
4359 4359  .na
4360 4360  \fB\fB[Y\fR\fR
4361 4361  .ad
4362 4362  .RS 13n
4363 4363  Move the cursor to the end of the line.
4364 4364  .RE
4365 4365  
4366 4366  .sp
4367 4367  .ne 2
4368 4368  .na
4369 4369  \fB\fB%\fR\fR
4370 4370  .ad
4371 4371  .RS 13n
4372 4372  Moves to balancing \fB(\fR, \fB)\fR, \fB{\fR, \fB}\fR, \fB[\fR, or \fB]\fR. If
4373 4373  cursor is not on one of the characters described in this section, the remainder
4374 4374  of the line is searched for the first occurrence of one of the characters
4375 4375  first.
4376 4376  .RE
4377 4377  
4378 4378  .SS "Search Edit Commands"
4379 4379  .sp
4380 4380  .LP
4381 4381  The search edit commands access your command history.
4382 4382  .sp
4383 4383  .LP
4384 4384  The following search edit commands are supported:
4385 4385  .sp
4386 4386  .ne 2
4387 4387  .na
4388 4388  \fB\fB[\fR\fIcount\fR\fB]k\fR\fR
4389 4389  .ad
4390 4390  .RS 13n
4391 4391  Fetch the previous command. Each time \fBk\fR is entered, the previous command
4392 4392  back in time is accessed.
4393 4393  .RE
4394 4394  
4395 4395  .sp
4396 4396  .ne 2
4397 4397  .na
4398 4398  \fB\fB[\fR\fIcount\fR\fB]-\fR\fR
4399 4399  .ad
4400 4400  .RS 13n
4401 4401  Fetch the previous command. Each time \fBk\fR is entered, the previous command
4402 4402  back in time is accessed.
4403 4403  .sp
4404 4404  Equivalent to \fBk\fR.
4405 4405  .RE
4406 4406  
4407 4407  .sp
4408 4408  .ne 2
4409 4409  .na
4410 4410  \fB\fB[\fR\fIcount\fR\fB][A\fR\fR
4411 4411  .ad
4412 4412  .RS 13n
4413 4413  Fetch the previous command. Each time \fBk\fR is entered, the previous command
4414 4414  back in time is accessed.
4415 4415  .sp
4416 4416  Equivalent to \fBk\fR.
4417 4417  .RE
4418 4418  
4419 4419  .sp
4420 4420  .ne 2
4421 4421  .na
4422 4422  \fB\fB[\fR\fIcount\fR\fB]j\fR\fR
4423 4423  .ad
4424 4424  .RS 13n
4425 4425  Fetch the next command. Each time \fBj\fR is entered, the next command forward
4426 4426  in time is accessed.
4427 4427  .RE
4428 4428  
4429 4429  .sp
4430 4430  .ne 2
4431 4431  .na
4432 4432  \fB\fB[\fR\fIcount\fR\fB]+\fR\fR
4433 4433  .ad
4434 4434  .RS 13n
4435 4435  Fetch the next command. Each time \fBj\fR is entered, the next command forward
4436 4436  in time is accessed.
4437 4437  .sp
4438 4438  Equivalent to \fBj\fR.
4439 4439  .RE
4440 4440  
4441 4441  .sp
4442 4442  .ne 2
4443 4443  .na
4444 4444  \fB\fB[\fR\fIcount\fR\fB][B\fR\fR
4445 4445  .ad
4446 4446  .RS 13n
4447 4447  Fetch the next command. Each time \fBj\fR is entered, the next command forward
4448 4448  in time is accessed.
4449 4449  .sp
4450 4450  Equivalent to \fBj\fR.
4451 4451  .RE
4452 4452  
4453 4453  .sp
4454 4454  .ne 2
4455 4455  .na
4456 4456  \fB\fB[\fR\fIcount\fR\fB]G\fR\fR
4457 4457  .ad
4458 4458  .RS 13n
4459 4459  Fetch command number \fIcount\fR. The default is the least recent history
4460 4460  command.
4461 4461  .RE
4462 4462  
4463 4463  .sp
4464 4464  .ne 2
4465 4465  .na
4466 4466  \fB\fB/\fR\fIstring\fR\fR
4467 4467  .ad
4468 4468  .RS 13n
4469 4469  Search backward through history for a previous command containing \fIstring\fR.
4470 4470  \fIstring\fR is terminated by a RETURN or NEWLINE. If string is preceded by a
4471 4471  \fB^\fR, the matched line must begin with \fIstring\fR. If \fIstring\fR is
4472 4472  null, the previous string is used.
4473 4473  .RE
4474 4474  
4475 4475  .sp
4476 4476  .ne 2
4477 4477  .na
4478 4478  \fB\fB?\fR\fIstring\fR\fR
4479 4479  .ad
4480 4480  .RS 13n
4481 4481  Search forward through history for a previous command containing \fIstring\fR.
4482 4482  \fIstring\fR is terminated by a RETURN or NEWLINE. If string is preceded by a
4483 4483  \fB^\fR, the matched line must begin with \fIstring\fR. If \fIstring\fR is
4484 4484  null, the previous string is used.
4485 4485  .sp
4486 4486  Same as \fI/\fR except that search is in the forward direction.
4487 4487  .RE
4488 4488  
4489 4489  .sp
4490 4490  .ne 2
4491 4491  .na
4492 4492  \fB\fBn\fR\fR
4493 4493  .ad
4494 4494  .RS 13n
4495 4495  Search in the backwards direction for the next match of the last pattern to
4496 4496  \fI/\fR or \fI?\fR commands.
4497 4497  .RE
4498 4498  
4499 4499  .sp
4500 4500  .ne 2
4501 4501  .na
4502 4502  \fB\fBN\fR\fR
4503 4503  .ad
4504 4504  .RS 13n
4505 4505  Search in the forward direction for next match of the last pattern to \fI/\fR
4506 4506  or \fI?\fR.
4507 4507  .RE
4508 4508  
4509 4509  .SS "Text Modification Edit Commands"
4510 4510  .sp
4511 4511  .LP
4512 4512  The following commands modify the line:
4513 4513  .sp
4514 4514  .ne 2
4515 4515  .na
4516 4516  \fB\fBa\fR\fR
4517 4517  .ad
4518 4518  .RS 19n
4519 4519  Enter input mode and enter text after the current character.
4520 4520  .RE
4521 4521  
4522 4522  .sp
4523 4523  .ne 2
4524 4524  .na
4525 4525  \fB\fBA\fR\fR
4526 4526  .ad
4527 4527  .RS 19n
4528 4528  Append text to the end of the line. Equivalent to \fB$a\fR.
4529 4529  .RE
4530 4530  
4531 4531  .sp
4532 4532  .ne 2
4533 4533  .na
4534 4534  \fB\fB[\fR\fIcount\fR\fB]c\fR\fImotion\fR\fR
4535 4535  .ad
4536 4536  .br
4537 4537  .na
4538 4538  \fB\fBc[\fR\fIcount\fR\fB]\fR\fImotion\fR\fR
4539 4539  .ad
4540 4540  .RS 19n
4541 4541  Delete current character through the character that \fImotion\fR would move the
4542 4542  cursor to and enter input mode. If \fImotion\fR is \fBc\fR, the entire line is
4543 4543  deleted and input mode entered.
4544 4544  .RE
4545 4545  
4546 4546  .sp
4547 4547  .ne 2
4548 4548  .na
4549 4549  \fB\fBC\fR\fR
4550 4550  .ad
4551 4551  .RS 19n
4552 4552  Delete the current character through the end of line and enter input mode.
4553 4553  Equivalent to \fBc$\fR.
4554 4554  .RE
4555 4555  
4556 4556  .sp
4557 4557  .ne 2
4558 4558  .na
4559 4559  \fB\fBS\fR\fR
4560 4560  .ad
4561 4561  .RS 19n
4562 4562  Equivalent to \fBcc\fR.
4563 4563  .RE
4564 4564  
4565 4565  .sp
4566 4566  .ne 2
4567 4567  .na
4568 4568  \fB\fB[\fR\fIcount\fR\fB]s\fR\fR
4569 4569  .ad
4570 4570  .RS 19n
4571 4571  Replace characters under the cursor in input mode.
4572 4572  .RE
4573 4573  
4574 4574  .sp
4575 4575  .ne 2
4576 4576  .na
4577 4577  \fB\fBD[\fR\fIcount\fR\fB]d\fR\fImotion\fR\fR
4578 4578  .ad
4579 4579  .RS 19n
4580 4580  Delete the current character through the end of line. Equivalent to d$.
4581 4581  .RE
4582 4582  
4583 4583  .sp
4584 4584  .ne 2
4585 4585  .na
4586 4586  \fB\fBd[\fR\fIcount\fR\fB]\fR\fImotion\fR\fR
4587 4587  .ad
4588 4588  .RS 19n
4589 4589  Delete current character through the character that \fImotion\fR would move to.
4590 4590  If \fImotion\fR is d , the entire line is deleted.
4591 4591  .RE
4592 4592  
4593 4593  .sp
4594 4594  .ne 2
4595 4595  .na
4596 4596  \fB\fBi\fR\fR
4597 4597  .ad
4598 4598  .RS 19n
4599 4599  Enter input mode and insert text before the current character.
4600 4600  .RE
4601 4601  
4602 4602  .sp
4603 4603  .ne 2
4604 4604  .na
4605 4605  \fB\fBI\fR\fR
4606 4606  .ad
4607 4607  .RS 19n
4608 4608  Insert text before the beginning of the line. Equivalent to \fB0i\fR.
4609 4609  .RE
4610 4610  
4611 4611  .sp
4612 4612  .ne 2
4613 4613  .na
4614 4614  \fB\fB[\fR\fIcount\fR\fB]P\fR\fR
4615 4615  .ad
4616 4616  .RS 19n
4617 4617  Place the previous text modification before the cursor.
4618 4618  .RE
4619 4619  
4620 4620  .sp
4621 4621  .ne 2
4622 4622  .na
4623 4623  \fB\fB[\fR\fIcount\fR\fB]p\fR\fR
4624 4624  .ad
4625 4625  .RS 19n
4626 4626  Place the previous text modification after the cursor.
4627 4627  .RE
4628 4628  
4629 4629  .sp
4630 4630  .ne 2
4631 4631  .na
4632 4632  \fB\fBR\fR\fR
4633 4633  .ad
4634 4634  .RS 19n
4635 4635  Enter input mode and replace characters on the screen with characters you type
4636 4636  overlay fashion.
4637 4637  .RE
4638 4638  
4639 4639  .sp
4640 4640  .ne 2
4641 4641  .na
4642 4642  \fB\fB[\fR\fIcount\fR\fB]r\fR\fIc\fR\fR
4643 4643  .ad
4644 4644  .RS 19n
4645 4645  Replace the \fIcount\fR characters starting at the current cursor position with
4646 4646  \fIc\fR, and advance the cursor.
4647 4647  .RE
4648 4648  
4649 4649  .sp
4650 4650  .ne 2
4651 4651  .na
4652 4652  \fB\fB[\fR\fIcount\fR\fB]x\fR\fR
4653 4653  .ad
4654 4654  .RS 19n
4655 4655  Delete current character.
4656 4656  .RE
4657 4657  
4658 4658  .sp
4659 4659  .ne 2
4660 4660  .na
4661 4661  \fB\fB[\fIcount\fR]X\fR\fR
4662 4662  .ad
4663 4663  .RS 19n
4664 4664  Delete preceding character.
4665 4665  .RE
4666 4666  
4667 4667  .sp
4668 4668  .ne 2
4669 4669  .na
4670 4670  \fB\fB[\fIcount\fR].\fR\fR
4671 4671  .ad
4672 4672  .RS 19n
4673 4673  Repeat the previous text modification command.
4674 4674  .RE
4675 4675  
4676 4676  .sp
4677 4677  .ne 2
4678 4678  .na
4679 4679  \fB\fB[\fIcount\fR]~\fR\fR
4680 4680  .ad
4681 4681  .RS 19n
4682 4682  Invert the case of the \fIcount\fR characters starting at the current cursor
4683 4683  position and advance the cursor.
4684 4684  .RE
4685 4685  
4686 4686  .sp
4687 4687  .ne 2
4688 4688  .na
4689 4689  \fB\fB[\fIcount\fR]_\fR\fR
4690 4690  .ad
4691 4691  .RS 19n
4692 4692  Causes the \fIcount\fR word of the previous command to be appended and input
4693 4693  mode entered. The last word is used if \fIcount\fR is omitted.
4694 4694  .RE
4695 4695  
4696 4696  .sp
4697 4697  .ne 2
4698 4698  .na
4699 4699  \fB\fB*\fR\fR
4700 4700  .ad
4701 4701  .RS 19n
4702 4702  Causes an \fB*\fR to be appended to the current word and file name generation
4703 4703  attempted. If no match is found, it rings the bell. Otherwise, the word is
4704 4704  replaced by the matching pattern and input mode is entered.
4705 4705  .RE
4706 4706  
4707 4707  .sp
4708 4708  .ne 2
4709 4709  .na
4710 4710  \fB\fB\e\fR\fR
4711 4711  .ad
4712 4712  .RS 19n
4713 4713  Command or file name completion as described in this manual page.
4714 4714  .RE
4715 4715  
4716 4716  .SS "Other Edit Commands"
4717 4717  .sp
4718 4718  .LP
4719 4719  The following miscellaneous edit commands are supported:
4720 4720  .sp
4721 4721  .ne 2
4722 4722  .na
4723 4723  \fB\fB[\fR\fIcount\fR\fB]y\fR\fImotion\fR\fR
4724 4724  .ad
4725 4725  .br
4726 4726  .na
4727 4727  \fB\fBy[\fR\fIcount\fR\fB]\fR\fImotion\fR\fR
4728 4728  .ad
4729 4729  .RS 18n
4730 4730  Yank the current character through the character to which \fImotion\fR would
4731 4731  move the cursor. Put the yanked characters in the delete buffer. The text and
4732 4732  cursor position are unchanged.
4733 4733  .RE
4734 4734  
4735 4735  .sp
4736 4736  .ne 2
4737 4737  .na
4738 4738  \fB\fByy\fR\fR
4739 4739  .ad
4740 4740  .RS 18n
4741 4741  Yank the current line.
4742 4742  .RE
4743 4743  
4744 4744  .sp
4745 4745  .ne 2
4746 4746  .na
4747 4747  \fB\fBY\fR\fR
4748 4748  .ad
4749 4749  .RS 18n
4750 4750  Yank the current line from the current cursor location to the end of the line.
4751 4751  Equivalent to \fBy$\fR.
4752 4752  .RE
4753 4753  
4754 4754  .sp
4755 4755  .ne 2
4756 4756  .na
4757 4757  \fB\fBu\fR\fR
4758 4758  .ad
4759 4759  .RS 18n
4760 4760  Undo the last text modifying command.
4761 4761  .RE
4762 4762  
4763 4763  .sp
4764 4764  .ne 2
4765 4765  .na
4766 4766  \fB\fBU\fR\fR
4767 4767  .ad
4768 4768  .RS 18n
4769 4769  Undo all the text modifying commands performed on current line.
4770 4770  .RE
4771 4771  
4772 4772  .sp
4773 4773  .ne 2
4774 4774  .na
4775 4775  \fB\fB[\fR\fIcount\fR\fB]V\fR\fR
4776 4776  .ad
4777 4777  .RS 18n
4778 4778  Return the command :
4779 4779  .sp
4780 4780  .in +2
4781 4781  .nf
4782 4782  hist -e ${VISUAL:-${EDITOR:-vi}} \fIcount\fR
4783 4783  .fi
4784 4784  .in -2
4785 4785  .sp
4786 4786  
4787 4787  in the input buffer. If \fIcount\fR is omitted, the current line is used.
4788 4788  .RE
4789 4789  
4790 4790  .sp
4791 4791  .ne 2
4792 4792  .na
4793 4793  \fB\fB^L\fR\fR
4794 4794  .ad
4795 4795  .RS 18n
4796 4796  Line feed and print the current line. This command only works in control mode.
4797 4797  .RE
4798 4798  
4799 4799  .sp
4800 4800  .ne 2
4801 4801  .na
4802 4802  \fB\fB^J\fR\fR
4803 4803  .ad
4804 4804  .RS 18n
4805 4805  New line. Execute the current line, regardless of mode.
4806 4806  .RE
4807 4807  
4808 4808  .sp
4809 4809  .ne 2
4810 4810  .na
4811 4811  \fB\fB^M\fR\fR
4812 4812  .ad
4813 4813  .RS 18n
4814 4814  Return. Execute the current line, regardless of mode.
4815 4815  .RE
4816 4816  
4817 4817  .sp
4818 4818  .ne 2
4819 4819  .na
4820 4820  \fB\fB#\fR\fR
4821 4821  .ad
4822 4822  .RS 18n
4823 4823  If the first character of the command is a \fB#\fR , delete this \fB#\fR and
4824 4824  each \fB#\fR that follows a NEWLINE.
4825 4825  .sp
4826 4826  Otherwise, send the line after inserting a \fB#\fR in front of each line in the
4827 4827  command.
4828 4828  .sp
4829 4829  This is command is useful for causing the current line to be inserted in the
4830 4830  history as a comment and un-commenting previously commented commands in the
4831 4831  history file.
4832 4832  .RE
4833 4833  
4834 4834  .sp
4835 4835  .ne 2
4836 4836  .na
4837 4837  \fB\fB[\fR\fIcount\fR\fB]=\fR\fR
4838 4838  .ad
4839 4839  .RS 18n
4840 4840  If \fIcount\fR is not specified, generate the list of matching commands or file
4841 4841  names as described in this manual page.
4842 4842  .sp
4843 4843  Otherwise, replace the word at the current cursor location with the \fIcount\fR
4844 4844  item from the most recently generated command or file list. If the cursor is
4845 4845  not on a word, it is inserted after the current cursor location.
4846 4846  .RE
4847 4847  
4848 4848  .sp
4849 4849  .ne 2
4850 4850  .na
4851 4851  \fB\fB@\fR\fIletter\fR\fR
4852 4852  .ad
4853 4853  .RS 18n
4854 4854  Search your alias list for an alias by the name \fIletter\fR. If an alias of
4855 4855  this name is defined, insert its value on the input queue for processing.
4856 4856  .RE
4857 4857  
4858 4858  .sp
4859 4859  .ne 2
4860 4860  .na
4861 4861  \fB\fB^V\fR\fR
4862 4862  .ad
4863 4863  .RS 18n
4864 4864  Display version of the shell.
4865 4865  .RE
4866 4866  
4867 4867  .SS "Built-in Commands"
4868 4868  .sp
4869 4869  .LP
4870 4870  The following simple-commands are executed in the shell process. Input and
4871 4871  output redirection is permitted. Unless otherwise indicated, the output is
4872 4872  written on file descriptor \fB1\fR and the exit status, when there is no syntax
4873 4873  error, is \fB0\fR. Except for \fB:\fR, \fBtrue\fR, \fBfalse\fR, \fBecho\fR,
4874 4874  \fBnewgrp\fR, and \fBlogin\fR, all built-in commands accept \fB--\fR to
4875 4875  indicate the end of options. They also interpret the option \fB--man\fR as a
4876 4876  request to display the manual page onto standard error and \fB-?\fR as a help
4877 4877  request which prints a usage message on standard error.
4878 4878  .sp
4879 4879  .LP
4880 4880  Commands that are preceded by one or two \fB++\fR symbols are special built-in
4881 4881  commands and are treated specially in the following ways:
4882 4882  .RS +4
4883 4883  .TP
4884 4884  1.
4885 4885  Variable assignment lists preceding the command remain in effect when the
4886 4886  command completes.
4887 4887  .RE
4888 4888  .RS +4
4889 4889  .TP
4890 4890  2.
4891 4891  I/O redirections are processed after variable assignments.
4892 4892  .RE
4893 4893  .RS +4
4894 4894  .TP
4895 4895  3.
4896 4896  Errors cause a script that contains them to abort.
4897 4897  .RE
4898 4898  .RS +4
4899 4899  .TP
4900 4900  4.
4901 4901  They are not valid function names.
4902 4902  .RE
4903 4903  .RS +4
4904 4904  .TP
4905 4905  5.
4906 4906  Words following a command preceded by \fB++\fR that are in the format of a
4907 4907  variable assignment are expanded with the same rules as a variable assignment.
4908 4908  This means that tilde substitution is performed after the \fB=\fR sign and
4909 4909  field splitting and file name generation are not performed.
4910 4910  .RE
4911 4911  .sp
4912 4912  .ne 2
4913 4913  .na
4914 4914  \fB\fB+ : [\fR\fIarg ...\fR\fB]\fR\fR
4915 4915  .ad
4916 4916  .sp .6
4917 4917  .RS 4n
4918 4918  The command only expands parameters.
4919 4919  .RE
4920 4920  
4921 4921  .sp
4922 4922  .ne 2
4923 4923  .na
4924 4924  \fB\fB+ .\fR \fIname\fR \fB[\fR\fIarg ...\fR\fB]\fR\fR
4925 4925  .ad
4926 4926  .sp .6
4927 4927  .RS 4n
4928 4928  If \fIname\fR is a function defined with the \fBfunction\fR \fBname\fR reserved
4929 4929  word syntax, the function is executed in the current environment (as if it had
4930 4930  been defined with the \fIname()\fR syntax.) Otherwise if \fIname\fR refers to a
4931 4931  file, the file is read in its entirety and the commands are executed in the
4932 4932  current shell environment. The search path specified by PATH is used to find
4933 4933  the directory containing the file. If any arguments \fIarg\fR are specified,
4934 4934  they become the positional parameters while processing the . command and the
4935 4935  original positional parameters are restored upon completion. Otherwise the
4936 4936  positional parameters are unchanged. The exit status is the exit status of the
4937 4937  last command executed.
4938 4938  .RE
4939 4939  
4940 4940  .sp
4941 4941  .ne 2
4942 4942  .na
4943 4943  \fB\fB++ alias [\fR\fB-ptx\fR\fB] [\fR\fIname\fR\fB[
4944 4944  =\fR\fIvalue\fR\fB]] ...\fR\fR
4945 4945  .ad
4946 4946  .sp .6
4947 4947  .RS 4n
4948 4948  \fBalias\fR with no arguments prints the list of aliases in the form
4949 4949  \fIname\fR\fB=\fR\fIvalue\fR on standard output. The \fB-p\fR option causes the
4950 4950  word alias to be inserted before each one. When one or more arguments are
4951 4951  specified, an \fIalias\fR is defined for each \fIname\fR whose \fIvalue\fR is
4952 4952  specified. A trailing space in \fIvalue\fR causes the next word to be checked
4953 4953  for alias substitution. The obsolete \fB-t\fR option is used to set and list
4954 4954  tracked aliases. The value of a tracked alias is the full pathname
4955 4955  corresponding to the specified \fIname\fR. The value becomes undefined when the
4956 4956  value of \fBPATH\fR is reset but the alias remains tracked. Without the
4957 4957  \fB-t\fR option, for each \fIname\fR in the argument list for which no
4958 4958  \fIvalue\fR is specified, the name and value of the alias is printed. The
4959 4959  obsolete -x option has no effect. The exit status is \fBnon-zero\fR if a
4960 4960  \fIname\fR is specified, but no value, and no alias has been defined for the
4961 4961  \fIname\fR.
4962 4962  .RE
4963 4963  
4964 4964  .sp
4965 4965  .ne 2
4966 4966  .na
4967 4967  \fB\fBbg [\fR \fIjob\fR\fB\&...]\fR\fR
4968 4968  .ad
4969 4969  .sp .6
4970 4970  .RS 4n
4971 4971  This command is only on systems that support job control. Puts each specified
4972 4972  \fIjob\fR into the background. The current job is put in the background if
4973 4973  \fIjob\fR is not specified. See the \fBJobs\fR section of this manual page for
4974 4974  a description of the format of \fIjob\fR.
4975 4975  .RE
4976 4976  
4977 4977  .sp
4978 4978  .ne 2
4979 4979  .na
4980 4980  \fB\fB+ break [\fR\fIn\fR\fB]\fR\fR
4981 4981  .ad
4982 4982  .sp .6
4983 4983  .RS 4n
4984 4984  Exit from the enclosing \fBfor\fR, \fBwhile\fR, \fBuntil\fR, or \fBselect\fR
4985 4985  loop, if any. If \fIn\fR is specified, then break \fIn\fR levels.
4986 4986  .RE
4987 4987  
4988 4988  .sp
4989 4989  .ne 2
4990 4990  .na
4991 4991  \fB\fBbuiltin [\fR\fB-ds\fR \fB] [\fR\fB-f\fR \fIfile\fR\fB]
4992 4992  [\fR\fIname ...\fR\fB]\fR\fR
4993 4993  .ad
4994 4994  .sp .6
4995 4995  .RS 4n
4996 4996  If \fIname\fR is not specified, and no \fB-f\fR option is specified, the
4997 4997  built-ins are printed on standard output. The \fB-s\fR option prints only the
4998 4998  special built-ins. Otherwise, each \fIname\fR represents the pathname whose
4999 4999  basename is the name of the built-in. The entry point function name is
5000 5000  determined by prepending \fIb\fR to the built-in name. The ISO C/C++ prototype
5001 5001  is \fBb\fR\fImycommand(int argc, char *argv[], void *context)\fR for the
5002 5002  built-in command \fImycommand\fR where \fIargv\fR is an array of \fIargc\fR
5003 5003  elements and \fIcontext\fR is an optional pointer to a \fBShell_t\fR structure
5004 5004  as described in \fB<ast/shell.h>\fR Special built-ins cannot be bound to a
5005 5005  pathname or deleted. The \fB-d\fR option deletes each of the specified
5006 5006  built-ins. On systems that support dynamic loading, the \fB-f\fR option names a
5007 5007  shared library containing the code for built-ins. The shared library prefix
5008 5008  and/or suffix, which depend on the system, can be omitted. Once a library is
5009 5009  loaded, its symbols become available for subsequent invocations of
5010 5010  \fBbuiltin\fR. Multiple libraries can be specified with separate invocations of
5011 5011  the \fBbuiltin\fR command. Libraries are searched in the reverse order in which
5012 5012  they are specified. When a library is loaded, it looks for a function in the
5013 5013  library whose name is \fBlib_init()\fR and invokes this function with an
5014 5014  argument of \fB0\fR.
5015 5015  .RE
5016 5016  
5017 5017  .sp
5018 5018  .ne 2
5019 5019  .na
5020 5020  \fB\fBcd\fR \fB[\fR\fB-LP\fR\fB] [\fR\fIarg\fR\fB]\fR\fR
5021 5021  .ad
5022 5022  .br
5023 5023  .na
5024 5024  \fB\fBcd\fR \fB[\fR\fB-LP\fR\fB]\fR \fIold\fR \fInew\fR\fR
5025 5025  .ad
5026 5026  .sp .6
5027 5027  .RS 4n
5028 5028  This command has two forms.
5029 5029  .sp
5030 5030  In the first form it changes the current directory to \fIarg\fR. If \fIarg\fR
5031 5031  is a \fB-\fR, the directory is changed to the previous directory. The shell
5032 5032  variable \fBHOME\fR is the default \fIarg\fR. The variable \fBPWD\fR is set to
5033 5033  the current directory. The shell variable \fBCDPATH\fR defines the search path
5034 5034  for the directory containing \fIarg\fR. Alternative directory names are
5035 5035  separated by a colon (\fB:\fR). The default path is \fBNULL\fR (specifying the
5036 5036  current directory). The current directory is specified by a null path name,
5037 5037  which can appear immediately after the equal sign or between the colon
5038 5038  delimiters anywhere else in the path list. If \fIarg\fR begins with a \fB/\fR,
5039 5039  the search path is not used. Otherwise, each directory in the path is searched
5040 5040  for \fIarg\fR.
5041 5041  .sp
5042 5042  The second form of \fBcd\fR substitutes the string \fInew\fR for the string
5043 5043  \fIold\fR in the current directory name, \fBPWD\fR, and tries to change to this
5044 5044  new directory. By default, symbolic link names are treated literally when
5045 5045  finding the directory name. This is equivalent to the \fB-L\fR option. The
5046 5046  \fB-P\fR option causes symbolic links to be resolved when determining the
5047 5047  directory. The last instance of \fB-L\fR or \fB-P\fR on the command line
5048 5048  determines which method is used. The \fBcd\fR command cannot be executed by
5049 5049  \fBrksh93\fR.
5050 5050  .RE
5051 5051  
5052 5052  .sp
5053 5053  .ne 2
5054 5054  .na
5055 5055  \fB\fBcommand\fR \fB[\fR\fB-pvVx\fR\fB]\fR \fIname\fR
5056 5056  \fB[\fR\fIarg ...\fR\fB]\fR\fR
5057 5057  .ad
5058 5058  .sp .6
5059 5059  .RS 4n
5060 5060  Without the \fB-v\fR or \fB-V\fR options, executes \fIname\fR with the
5061 5061  arguments specified by \fIarg\fR.
5062 5062  .sp
5063 5063  The \fB-p\fR option causes a default path to be searched rather than the one
5064 5064  defined by the value of \fBPATH\fR. Functions are not searched when finding
5065 5065  \fIname\fR. In addition, if \fIname\fR refers to a special built-in, none of
5066 5066  the special properties associated with the leading daggers are honored. For
5067 5067  example, the predefined alias \fBredirect='command exec'\fR prevents a script
5068 5068  from terminating when an invalid redirection is specified.
5069 5069  .sp
5070 5070  With the \fB-x\fR option, if command execution would result in a failure
5071 5071  because there are too many arguments, \fBerrno E2BIG\fR, the shell invokes
5072 5072  command \fIname\fR multiple times with a subset of the arguments on each
5073 5073  invocation. Arguments that occur prior to the first word that expands to
5074 5074  multiple arguments and after the last word that expands to multiple arguments
5075 5075  are passed on each invocation. The exit status is the maximum invocation exit
5076 5076  status.
5077 5077  .sp
5078 5078  With the \fB-v\fR option, \fBcommand\fR is equivalent to the built-in
5079 5079  \fBwhence\fR command described in this section. The \fB-V\fR option causes
5080 5080  \fBcommand\fR to act like \fBwhence -v\fR.
5081 5081  .RE
5082 5082  
5083 5083  .sp
5084 5084  .ne 2
5085 5085  .na
5086 5086  \fB\fB+continue\fR \fB[\fR\fIn\fR\fB]\fR\fR
5087 5087  .ad
5088 5088  .sp .6
5089 5089  .RS 4n
5090 5090  Resumes the next iteration of the enclosing \fBfor\fR, \fBwhile\fR,
5091 5091  \fBuntil\fR, or \fBselect\fR loop. If \fIn\fR is specified, then resume at the
5092 5092  \fIn\fRth enclosing loop.
5093 5093  .RE
5094 5094  
5095 5095  .sp
5096 5096  .ne 2
5097 5097  .na
5098 5098  \fB\fBdisown\fR \fB[\fR\fIjob...\fR\fB]\fR\fR
5099 5099  .ad
5100 5100  .sp .6
5101 5101  .RS 4n
5102 5102  Causes the shell not to send a \fBHUP\fR signal to each specified \fIjob\fR, or
5103 5103  all active jobs if \fIjob\fR is omitted, when a login shell terminates.
5104 5104  .RE
5105 5105  
5106 5106  .sp
5107 5107  .ne 2
5108 5108  .na
5109 5109  \fB\fBecho\fR \fB[\fR\fIarg ...\fR\fB]\fR\fR
5110 5110  .ad
5111 5111  .sp .6
5112 5112  .RS 4n
5113 5113  When the first \fIarg\fR does not begin with a \fB-\fR, and none of the
5114 5114  arguments contain a backslash (\fB\e\fR), prints each of its arguments
5115 5115  separated by a SPACE and terminated by a NEWLINE. Otherwise, the behavior of
5116 5116  \fBecho\fR is system dependent and \fBprint\fR or \fBprintf\fR described in
5117 5117  this section should be used. See \fBecho\fR(1) for usage and description.
5118 5118  .RE
5119 5119  
5120 5120  .sp
5121 5121  .ne 2
5122 5122  .na
5123 5123  \fB\fB+eval\fR \fB[\fR\fIarg ...\fR\fB]\fR\fR
5124 5124  .ad
5125 5125  .sp .6
5126 5126  .RS 4n
5127 5127  The arguments are read as input to the shell and the resulting commands are
5128 5128  executed.
5129 5129  .RE
5130 5130  
5131 5131  .sp
5132 5132  .ne 2
5133 5133  .na
5134 5134  \fB\fB+exec\fR [\fB-c\fR] [\fB-a\fR \fIname ...\fR]
5135 5135  \fB[\fR\fIarg ...\fR\fB]\fR\fR
5136 5136  .ad
5137 5137  .sp .6
5138 5138  .RS 4n
5139 5139  If \fIarg\fR is specified, the command specified by the arguments is executed
5140 5140  in place of this shell without creating a new process. The \fB-c\fR option
5141 5141  causes the environment to be cleared before applying variable assignments
5142 5142  associated with the exec invocation. The \fB-a\fR option causes \fIname\fR
5143 5143  rather than the first \fIarg\fR, to become \fBargv[0]\fR for the new process.
5144 5144  Input and output arguments can appear and affect the current process. If
5145 5145  \fIarg\fR is not specified, the effect of this command is to modify file
5146 5146  descriptors as prescribed by the input/output redirection list. In this case,
5147 5147  any file descriptor numbers greater than \fB2\fR that are opened with this
5148 5148  mechanism are closed when invoking another program.
5149 5149  .RE
5150 5150  
5151 5151  .sp
5152 5152  .ne 2
5153 5153  .na
5154 5154  \fB\fB+exit\fR \fB[\fR\fIn\fR\fB]\fR\fR
5155 5155  .ad
5156 5156  .sp .6
5157 5157  .RS 4n
5158 5158  Causes the shell to exit with the exit status specified by \fIn\fR. The value
5159 5159  is the least significant 8 bits of the specified status. If \fIn\fR is omitted,
5160 5160  then the exit status is that of the last command executed. An end-of-file also
5161 5161  causes the shell to exit except for a shell which has the \fBignoreeof\fR
5162 5162  option turned on. See \fBset\fR.
5163 5163  .RE
5164 5164  
5165 5165  .sp
5166 5166  .ne 2
5167 5167  .na
5168 5168  \fB\fB++export\fR \fB[\fR\fB-p\fR\fB]\fR
5169 5169  \fB[\fR\fIname\fR\fB[=\fR\fIvalue\fR\fB]] ...\fR\fR
5170 5170  .ad
5171 5171  .sp .6
5172 5172  .RS 4n
5173 5173  If \fIname\fR is not specified, the names and values of each variable with the
5174 5174  export attribute are printed with the values quoted in a manner that allows
5175 5175  them to be re-entered. The \fB-p\fR option causes the word export to be
5176 5176  inserted before each one. Otherwise, the specified \fIname\fRs are marked for
5177 5177  automatic export to the environment of subsequently-executed commands.
5178 5178  .RE
5179 5179  
5180 5180  .sp
5181 5181  .ne 2
5182 5182  .na
5183 5183  \fB\fBfalse\fR\fR
5184 5184  .ad
5185 5185  .sp .6
5186 5186  .RS 4n
5187 5187  Does nothing, and exits \fB1\fR. Used with \fBuntil\fR for infinite loops.
5188 5188  .RE
5189 5189  
5190 5190  .sp
5191 5191  .ne 2
5192 5192  .na
5193 5193  \fB\fBfg\fR \fB[\fR\fIjob ...\fR\fB]\fR\fR
5194 5194  .ad
5195 5195  .sp .6
5196 5196  .RS 4n
5197 5197  This command is only on systems that support job control. Each \fIjob\fR
5198 5198  specified is brought to the foreground and waited for in the specified order.
5199 5199  Otherwise, the current job is brought into the foreground. See \fBJobs\fR for a
5200 5200  description of the format of \fIjob\fR.
5201 5201  .RE
5202 5202  
5203 5203  .sp
5204 5204  .ne 2
5205 5205  .na
5206 5206  \fB\fBgetconf\fR \fB[\fR\fIname\fR \fB[\fR\fIpathname\fR\fB]]\fR\fR
5207 5207  .ad
5208 5208  .sp .6
5209 5209  .RS 4n
5210 5210  Prints the current value of the configuration parameter specified by
5211 5211  \fIname\fR. The configuration parameters are defined by the IEEE POSIX 1003.1
5212 5212  and IEEE POSIX 1003.2 standards. See \fBpathconf\fR(2) and \fBsysconf\fR(3C).
5213 5213  .sp
5214 5214  The \fIpathname\fR argument is required for parameters whose value depends on
5215 5215  the location in the file system. If no arguments are specified, \fBgetconf\fR
5216 5216  prints the names and values of the current configuration parameters. The
5217 5217  pathname \fB/\fR is used for each of the parameters that requires
5218 5218  \fIpathname\fR.
5219 5219  .RE
5220 5220  
5221 5221  .sp
5222 5222  .ne 2
5223 5223  .na
5224 5224  \fB\fBgetopts\fR \fB[\fR \fB-a\fR \fIname\fR\fB]\fR \fIoptstring\fR \fIvname\fR
5225 5225  \fB[\fR\fIarg ...\fR\fB]\fR\fR
5226 5226  .ad
5227 5227  .sp .6
5228 5228  .RS 4n
5229 5229  Checks \fIarg\fR for legal options. If \fIarg\fR is omitted, the positional
5230 5230  parameters are used. An option argument begins with a \fB+\fR or a \fB-\fR. An
5231 5231  option that does not begin with \fB+\fR or \fB-\fR or the argument \fB--\fR
5232 5232  ends the options. Options beginning with \fB+\fR are only recognized when
5233 5233  \fIoptstring\fR begins with a \fB+\fR. \fIoptstring\fR contains the letters
5234 5234  that \fBgetopts\fR recognizes. If a letter is followed by a \fB:\fR, that
5235 5235  option is expected to have an argument. The options can be separated from the
5236 5236  argument by blanks. The option \fB-?\fRcauses \fBgetopts\fR to generate a usage
5237 5237  message on standard error. The \fB-a\fR option can be used to specify the name
5238 5238  to use for the usage message, which defaults to $0. \fBgetopts\fR places the
5239 5239  next option letter it finds inside variable \fIvname\fR each time it is
5240 5240  invoked. The option letter is prepended with a \fB+\fR when \fIarg\fR begins
5241 5241  with a \fB+\fR. The index of the next \fIarg\fR is stored in \fBOPTIND\fR. The
5242 5242  option argument, if any, gets stored in \fBOPTARG\fR. A leading : in
5243 5243  \fIoptstring\fR causes \fBgetopts\fR to store the letter of an invalid option
5244 5244  in \fBOPTARG\fR, and to set \fIvname\fR to \fB?\fR for an unknown option and
5245 5245  to: when a required option argument is missing. Otherwise, \fBgetopts\fR prints
5246 5246  an error message. The exit status is \fBnon-zero\fR when there are no more
5247 5247  options. There is no way to specify any of the options \fB:\fR, \fB+\fR,
5248 5248  \fB-\fR, \fB?\fR, \fB[\fR, and \fB]\fR. The option \fB#\fR can only be
5249 5249  specified as the first option.
5250 5250  .RE
5251 5251  
5252 5252  .sp
5253 5253  .ne 2
5254 5254  .na
5255 5255  \fB\fBhist\fR \fB[\fR \fB-e\fR \fIename\fR\fB]\fR\fB[\fR\fB-nlr\fR\fB]\fR
5256 5256  \fB[\fR \fIfirst\fR\fB[\fR\fIlast\fR \fB] ]\fR\fR
5257 5257  .ad
5258 5258  .br
5259 5259  .na
5260 5260  \fB\fR
5261 5261  .ad
5262 5262  .br
5263 5263  .na
5264 5264  \fB\fBhist\fR \fB-s\fR \fB[\fR \fIold\fR\fB=\fR\fInew\fR \fB] [\fR
5265 5265  \fIcommand\fR\fB]\fR\fR
5266 5266  .ad
5267 5267  .sp .6
5268 5268  .RS 4n
5269 5269  In the first form, a range of commands from \fIfirst\fR to \fIlast\fR is
5270 5270  selected from the last \fBHISTSIZE\fR commands that were typed at the terminal.
5271 5271  The arguments \fIfirst\fR and \fIlast\fR can be specified as a number or as a
5272 5272  string. A string is used to locate the most recent command starting with the
5273 5273  specified string. A negative number is used as an offset to the current command
5274 5274  number. If the -l option is selected, the commands are listed on standard
5275 5275  output. Otherwise, the editor program \fIename\fR is invoked on a file
5276 5276  containing these keyboard commands. If \fIename\fR is not supplied, then the
5277 5277  value of the variable \fBHISTEDIT\fR is used. If \fBHISTEDIT\fR is not set,
5278 5278  then \fBFCEDIT\fR (default \fB/bin/ed\fR) is used as the editor. When editing
5279 5279  is complete, the edited command(s) is executed if the changes have been saved.
5280 5280  If \fIlast\fR is not specified, then it is set to \fIfirst\fR. If \fIfirst\fR
5281 5281  is not specified, the default is the previous command for editing and \fB-16\fR
5282 5282  for listing. The option \fB-r\fR reverses the order of the commands and the
5283 5283  option \fB-n\fR suppresses command numbers when listing. In the second form,
5284 5284  \fIcommand\fR is interpreted as \fIfirst\fR described in this section and
5285 5285  defaults to the last command executed. The resulting command is executed after
5286 5286  the optional substitution \fIold\fR\fB=\fR\fInew\fR is performed.
5287 5287  .RE
5288 5288  
5289 5289  .sp
5290 5290  .ne 2
5291 5291  .na
5292 5292  \fB\fBjobs\fR \fB-lnp\fR \fB[\fR\fIjob ...\fR\fB]\fR\fR
5293 5293  .ad
5294 5294  .sp .6
5295 5295  .RS 4n
5296 5296  Lists information about each specified job, or all active jobs if \fIjob\fR is
5297 5297  omitted. The \fB-l\fR option lists process ids in addition to the normal
5298 5298  information. The \fB-n\fR option only displays jobs that have stopped or exited
5299 5299  since last notified. The \fB-p\fR option causes only the process group to be
5300 5300  listed. See \fBJobs\fR for a description of the format of \fIjob\fR.
5301 5301  .RE
5302 5302  
5303 5303  .sp
5304 5304  .ne 2
5305 5305  .na
5306 5306  \fB\fBkill\fR \fB[\fR\fB-s\fR \fIsigname\fR\fB]\fR \fIjob ...\fR\fR
5307 5307  .ad
5308 5308  .br
5309 5309  .na
5310 5310  \fB\fBkill\fR \fB[\fR\fB-n\fR \fIsignum\fR\fB]\fR \fIjob ...\fR\fR
5311 5311  .ad
5312 5312  .br
5313 5313  .na
5314 5314  \fB\fBkill\fR \fB-l\fR \fB[\fR\fIsig ...\fR\fB]\fR\fR
5315 5315  .ad
5316 5316  .sp .6
5317 5317  .RS 4n
5318 5318  Sends either the \fBTERM\fR (terminate) signal or the specified signal to the
5319 5319  specified jobs or processes. Signals are either specified by number with the
5320 5320  \fB-n\fR option or by name with the \fB-s\fR option (as specified in
5321 5321  \fB<signal.h\fR>, stripped of the prefix `\fBSIG\fR with the exception that
5322 5322  \fBSIGCLD\fR is named \fBCHLD\fR). For backward compatibility, the \fBn\fR and
5323 5323  \fBs\fR can be omitted and the number or name placed immediately after the
5324 5324  \fB-\fR. If the signal being sent is \fBTERM\fR (terminate) or \fBHUP\fR (hang
5325 5325  up), then the job or process is sent a \fBCONT\fR (continue) signal if it is
5326 5326  stopped. The argument \fIjob\fR can be the process id of a process that is not
5327 5327  a member of one of the active jobs. See \fBJobs\fR for a description of the
5328 5328  format of \fIjob\fR. In the third form, \fBkill -l\fR, if \fIsig\fR is not
5329 5329  specified, the signal names are listed. Otherwise, for each \fIsig\fR that is a
5330 5330  name, the corresponding signal number is listed. For each \fIsig\fR that is a
5331 5331  number, the signal name corresponding to the least significant 8 bits of
5332 5332  \fIsig\fR is listed.
5333 5333  .RE
5334 5334  
5335 5335  .sp
5336 5336  .ne 2
5337 5337  .na
5338 5338  \fB\fBlet\fR \fB[\fR\fIarg ...\fR\fB]\fR\fR
5339 5339  .ad
5340 5340  .sp .6
5341 5341  .RS 4n
5342 5342  Each \fIarg\fR is a separate arithmetic expression to be evaluated. See the
5343 5343  \fBArithmetic Evaluation\fR section of this manual page for a description of
5344 5344  arithmetic expression evaluation. The exit status is \fB0\fR if the value of
5345 5345  the last expression is \fBnon-zero\fR, and \fB1\fR otherwise.
5346 5346  .RE
5347 5347  
5348 5348  .sp
5349 5349  .ne 2
5350 5350  .na
5351 5351  \fB\fB+newgrp\fR \fB[\fR\fIarg ...\fR\fB]\fR\fR
5352 5352  .ad
5353 5353  .sp .6
5354 5354  .RS 4n
5355 5355  Equivalent to \fBexec\fR \fB/bin/newgrp\fR \fIarg ...\fR
5356 5356  .RE
5357 5357  
5358 5358  .sp
5359 5359  .ne 2
5360 5360  .na
5361 5361  \fB\fBprint\fR [\fB-Renprs\fR] \fB[\fR \fB-u\fR \fIunit\fR\fB] [\fR \fB-f\fR
5362 5362  \fIformat\fR \fB] [\fR \fIarg ...\fR\fB]\fR\fR
5363 5363  .ad
5364 5364  .sp .6
5365 5365  .RS 4n
5366 5366  With no options or with option \fB-\fR or \fB--\fR, each \fIarg\fR is printed
5367 5367  on standard output. The \fB-f\fR option causes the arguments to be printed as
5368 5368  described by \fBprintf\fR. In this case, any \fBe\fR, \fBn\fR, \fBr\fR, or
5369 5369  \fBR\fR options are ignored. Otherwise, unless the \fB-R\fR or \fB-r,\fR are
5370 5370  specified, the following escape conventions are applied:
5371 5371  .sp
5372 5372  .ne 2
5373 5373  .na
5374 5374  \fB\fB\ea\fR\fR
5375 5375  .ad
5376 5376  .RS 8n
5377 5377  Alert character (\fBASCII\fR 07)
5378 5378  .RE
5379 5379  
5380 5380  .sp
5381 5381  .ne 2
5382 5382  .na
5383 5383  \fB\fB\eb\fR\fR
5384 5384  .ad
5385 5385  .RS 8n
5386 5386  Backspace character (\fBASCII\fR 010)
5387 5387  .RE
5388 5388  
5389 5389  .sp
5390 5390  .ne 2
5391 5391  .na
5392 5392  \fB\fB\ec\fR\fR
5393 5393  .ad
5394 5394  .RS 8n
5395 5395  Causes print to end without processing more arguments and not adding a NEWLINE
5396 5396  .RE
5397 5397  
5398 5398  .sp
5399 5399  .ne 2
5400 5400  .na
5401 5401  \fB\fB\ef\fR\fR
5402 5402  .ad
5403 5403  .RS 8n
5404 5404  Form-feed character (\fBASCII\fR 014)
5405 5405  .RE
5406 5406  
5407 5407  .sp
5408 5408  .ne 2
5409 5409  .na
5410 5410  \fB\fB\en\fR\fR
5411 5411  .ad
5412 5412  .RS 8n
5413 5413  NEWLINE character (\fBASCII\fR 012)
5414 5414  .RE
5415 5415  
5416 5416  .sp
5417 5417  .ne 2
5418 5418  .na
5419 5419  \fB\fB\er\fR\fR
5420 5420  .ad
5421 5421  .RS 8n
5422 5422  RETURN character (\fBASCII\fR 015)
5423 5423  .RE
5424 5424  
5425 5425  .sp
5426 5426  .ne 2
5427 5427  .na
5428 5428  \fB\fB\et\fR\fR
5429 5429  .ad
5430 5430  .RS 8n
5431 5431  TAB character (\fBASCII\fR 011)
5432 5432  .RE
5433 5433  
5434 5434  .sp
5435 5435  .ne 2
5436 5436  .na
5437 5437  \fB\fB\ev\fR\fR
5438 5438  .ad
5439 5439  .RS 8n
5440 5440  Vertical TAB character (\fBASCII\fR 013)
5441 5441  .RE
5442 5442  
5443 5443  .sp
5444 5444  .ne 2
5445 5445  .na
5446 5446  \fB\fB\eE\fR\fR
5447 5447  .ad
5448 5448  .RS 8n
5449 5449  Escape character (\fBASCII\fR 033)
5450 5450  .RE
5451 5451  
5452 5452  .sp
5453 5453  .ne 2
5454 5454  .na
5455 5455  \fB\fB\e\e\fR\fR
5456 5456  .ad
5457 5457  .RS 8n
5458 5458  Backslash character \fB\e\fR
5459 5459  .RE
5460 5460  
5461 5461  .sp
5462 5462  .ne 2
5463 5463  .na
5464 5464  \fB\fB\e0\fR\fIx\fR\fR
5465 5465  .ad
5466 5466  .RS 8n
5467 5467  Character defined by the 1, 2, or 3-digit octal string specified by \fIx\fR
5468 5468  .RE
5469 5469  
5470 5470  The \fB-R\fR option prints all subsequent arguments and options other than
5471 5471  \fB-n\fR. The \fB-e\fR causes the escape conventions to be applied This is the
5472 5472  default behavior. It reverses the effect of an earlier \fB-r\fR. The \fB-p\fR
5473 5473  option causes the arguments to be written onto the pipe of the process spawned
5474 5474  with \fB|&\fR instead of standard output. The \fB-s\fR option causes the
5475 5475  arguments to be written onto the history file instead of standard output. The
5476 5476  \fB-u\fR option can be used to specify a one digit file descriptor unit number
5477 5477  \fIunit\fR on which the output is placed. The default is \fB1\fR. If the option
5478 5478  \fB-n\fR is used, no NEWLINE is added to the output.
5479 5479  .RE
5480 5480  
5481 5481  .sp
5482 5482  .ne 2
5483 5483  .na
5484 5484  \fB\fBprintf\fR \fIformat\fR\fB[\fR\fIarg ...\fR\fB]\fR\fR
5485 5485  .ad
5486 5486  .sp .6
5487 5487  .RS 4n
5488 5488  The arguments \fIarg\fR are printed on standard output in accordance with the
5489 5489  \fBANSI-C\fR formatting rules associated with the format string \fIformat\fR.
5490 5490  If the number of arguments exceeds the number of format specifications, the
5491 5491  format string is reused to format remaining arguments. The following extensions
5492 5492  can also be used: A \fB%b\fR format can be used instead of \fB%s\fR to cause
5493 5493  escape sequences in the corresponding \fIarg\fR to be expanded as described in
5494 5494  \fBprint\fR. A \fB%B\fR option causes each of the arguments to be treated as
5495 5495  variable names and the binary value of the variables is printed. This is most
5496 5496  useful for variables with an attribute of b. A \fB%H\fR format can be used
5497 5497  instead of \fB%s\fR to cause characters in \fIarg\fR that are special in
5498 5498  \fBHTML\fR and \fBXML\fR to be output as their entity name. A \fB%P\fR format
5499 5499  can be used instead of \fB%s\fR to cause \fIarg\fR to be interpreted as an
5500 5500  extended regular expression and be printed as a shell pattern. A \fB%R\fR
5501 5501  format can be used instead of \fB%s\fR to cause \fIarg\fR to be interpreted as
5502 5502  a shell pattern and to be printed as an extended regular expression. A \fB%q\fR
5503 5503  format can be used instead of \fB%\fRs to cause the resulting string to be
5504 5504  quoted in a manner than can be input again to the shell. A
5505 5505  \fB%(\fR\fIdate-format\fR\fB)T\fR format can be use to treat an argument as a
5506 5506  date/time string and to format the date/time according to the \fIdate-format\fR
5507 5507  as defined for the \fBdate\fR(1) command. A \fB%Z\fR format outputs a byte
5508 5508  whose value is 0. The precision field of the %d format can be followed by a .
5509 5509  and the output base. In this case, the \fB#\fR flag character causes
5510 5510  \fBbase\fR\fI#\fR to be prepended. The \fB#\fR flag when used with the \fBd\fR
5511 5511  specifier without an output base, causes the output to be displayed in
5512 5512  thousands units with one of the suffixes \fBk\fR \fBM\fR \fBG\fR \fBT\fR
5513 5513  \fBP\fR \fBE\fR to indicate the unit. The \fB#\fR flag when used with the i
5514 5514  specifier causes the output to be displayed in \fB1024\fR with one of the
5515 5515  suffixes \fBKi\fR \fBMi\fR \fBGi\fR \fBTi\fR \fBPi\fR \fBEi\fR to indicate the
5516 5516  unit. The \fB=\fR flag has been added to center the output within the specified
5517 5517  field width.
5518 5518  .RE
5519 5519  
5520 5520  .sp
5521 5521  .ne 2
5522 5522  .na
5523 5523  \fB\fBpwd\fR [\fB-LP\fR]\fR
5524 5524  .ad
5525 5525  .sp .6
5526 5526  .RS 4n
5527 5527  Outputs the value of the current working directory. The \fB-L\fR option is the
5528 5528  default. It prints the logical name of the current directory. If the \fB-P\fR
5529 5529  option is specified, all symbolic links are resolved from the name. The last
5530 5530  instance of \fB-L\fR or \fB-P\fR on the command line determines which method is
5531 5531  used.
5532 5532  .RE
5533 5533  
5534 5534  .sp
5535 5535  .ne 2
5536 5536  .na
5537 5537  \fB\fBread\fR \fB[\fR\fB-Aprs\fR\fB] [\fR\fB-d\fR \fIdelim\fR\fB] [\fR \fB-n\fR
5538 5538  \fIn\fR\fB] [[\fR \fB-N\fR \fIn\fR\fB] [[\fR\fB-t\fR \fItimeout\fR\fB]
5539 5539  [\fR\fB-u\fR \fIunit\fR\fB] [\fR\fIvname\fR\fB?\fR\fIprompt\fR\fB] [\fR
5540 5540  \fIvname ...\fR \fB]\fR\fR
5541 5541  .ad
5542 5542  .sp .6
5543 5543  .RS 4n
5544 5544  The shell input mechanism. One line is read and is broken up into fields using
5545 5545  the characters in IFS as separators. The escape character, \fB\e\fR, is used to
5546 5546  remove any special meaning for the next character and for line continuation.
5547 5547  The \fB-d\fR option causes the read to continue to the first character of
5548 5548  \fIdelim\fR rather than \fBNEWLINE\fR. The \fB-n\fR option causes at most
5549 5549  \fIn\fR bytes to read rather a full line but returns when reading from a slow
5550 5550  device as soon as any characters have been read. The \fB-N\fR option causes
5551 5551  exactly \fIn\fR to be read unless an end-of-file has been encountered or the
5552 5552  read times out because of the \fB-t\fR option. In raw mode, \fB-r\fR, the
5553 5553  \fB\e\fR character is not treated specially. The first field is assigned to the
5554 5554  first \fIvname\fR, the second field to the second \fIvname\fR, etc., with
5555 5555  leftover fields assigned to the last \fIvname\fR. When \fIvname\fR has the
5556 5556  binary attribute and \fB-n\fR or \fB-N\fR is specified, the bytes that are read
5557 5557  are stored directly into the variable. If the -v is specified, then the value
5558 5558  of the first \fIvname\fR is used as a default value when reading from a
5559 5559  terminal device. The \fB-A\fR option causes the variable \fIvname\fR to be
5560 5560  unset and each field that is read to be stored in successive elements of the
5561 5561  indexed array \fIvname\fR. The \fB-p\fR option causes the input line to be
5562 5562  taken from the input pipe of a process spawned by the shell using \fB|&\fR. If
5563 5563  the \fB-s\fR option is present, the input is saved as a command in the history
5564 5564  file. The option \fB-u\fR can be used to specify a one digit file descriptor
5565 5565  unit \fIunit\fR to read from. The file descriptor can be opened with the
5566 5566  \fBexec\fR special built-in command. The default value of unit \fIn\fR is
5567 5567  \fB0\fR. The option \fB-t\fR is used to specify a time out in seconds when
5568 5568  reading from a terminal or pipe. If \fIvname\fR is omitted, then REPLY is used
5569 5569  as the default \fIvname\fR. An end-of-file with the \fB-p\fR option causes
5570 5570  cleanup for this process so that another can be spawned. If the first argument
5571 5571  contains a \fB?\fR, the remainder of this word is used as a prompt on standard
5572 5572  error when the shell is interactive. The exit status is \fB0\fR unless an
5573 5573  end-of-file is encountered or read has timed out.
5574 5574  .RE
5575 5575  
5576 5576  .sp
5577 5577  .ne 2
5578 5578  .na
5579 5579  \fB\fB++readonly\fR \fB[\fR\fB-p\fR\fB] [\fR
5580 5580  \fIvname\fR\fB[=\fR\fIvalue\fR\fB]] ...\fR\fR
5581 5581  .ad
5582 5582  .sp .6
5583 5583  .RS 4n
5584 5584  If \fIvname\fR is not specified, the names and values of each variable with the
5585 5585  read-only attribute is printed with the values quoted in a manner that allows
5586 5586  them to be input again. The \fB-p\fR option causes the word \fBreadonly\fR to
5587 5587  be inserted before each one. Otherwise, the specified \fIvname\fRs are marked
5588 5588  \fBreadonly\fR and these names cannot be changed by subsequent assignment.
5589 5589  .RE
5590 5590  
5591 5591  .sp
5592 5592  .ne 2
5593 5593  .na
5594 5594  \fB\fB+return\fR \fB[\fR\fIn\fR\fB]\fR\fR
5595 5595  .ad
5596 5596  .sp .6
5597 5597  .RS 4n
5598 5598  Causes a shell function or script to return to the invoking script with the
5599 5599  exit status specified by \fIn\fR. The value is the least significant 8 bits of
5600 5600  the specified status. If \fBn\fR is omitted, then the return status is that of
5601 5601  the last command executed. If return is invoked while not in a function or a
5602 5602  script, then it behaves the same as exit.
5603 5603  .RE
5604 5604  
5605 5605  .sp
5606 5606  .ne 2
5607 5607  .na
5608 5608  \fB\fB+set [ \(+-BCGabefhkmnoprstuvx] [\(+-o [\fR \fIoption\fR \fB] ] ... [
5609 5609  \(+-A\fR \fIvname\fR\fB]\fR \fB[\fR\fIarg...\fR\fB]\fR\fR
5610 5610  .ad
5611 5611  .sp .6
5612 5612  .RS 4n
5613 5613  The \fBset\fR command supports the following options:
5614 5614  .sp
5615 5615  .ne 2
5616 5616  .na
5617 5617  \fB\fB-a\fR\fR
5618 5618  .ad
5619 5619  .sp .6
5620 5620  .RS 4n
5621 5621  All subsequent variables that are defined are automatically exported.
5622 5622  .RE
5623 5623  
5624 5624  .sp
5625 5625  .ne 2
5626 5626  .na
5627 5627  \fB\fB-A\fR\fR
5628 5628  .ad
5629 5629  .sp .6
5630 5630  .RS 4n
5631 5631  Array assignment. Unset the variable \fIvname\fR and assign values sequentially
5632 5632  from the \fIarg\fR list. If \fB+A\fR is used, the variable \fIvname\fR is not
5633 5633  unset first.
5634 5634  .RE
5635 5635  
5636 5636  .sp
5637 5637  .ne 2
5638 5638  .na
5639 5639  \fB\fB-b\fR\fR
5640 5640  .ad
5641 5641  .sp .6
5642 5642  .RS 4n
5643 5643  Prints job completion messages as soon as a background job changes state rather
5644 5644  than waiting for the next prompt.
5645 5645  .RE
5646 5646  
5647 5647  .sp
5648 5648  .ne 2
5649 5649  .na
5650 5650  \fB\fB-B\fR\fR
5651 5651  .ad
5652 5652  .sp .6
5653 5653  .RS 4n
5654 5654  Enable brace pattern field generation. This is the default behavior.
5655 5655  .RE
5656 5656  
5657 5657  .sp
5658 5658  .ne 2
5659 5659  .na
5660 5660  \fB\fB-C\fR\fR
5661 5661  .ad
5662 5662  .sp .6
5663 5663  .RS 4n
5664 5664  Prevents redirection (\fB>\fR) from truncating existing files. Files that are
5665 5665  created are opened with the \fBO_EXCL\fR mode. Requires \fB>|\fR to truncate a
5666 5666  file when turned on.
5667 5667  .RE
5668 5668  
5669 5669  .sp
5670 5670  .ne 2
5671 5671  .na
5672 5672  \fB\fB-e\fR\fR
5673 5673  .ad
5674 5674  .sp .6
5675 5675  .RS 4n
5676 5676  If a command has a \fBnon-zero\fR exit status, execute the \fBERR\fR trap, if
5677 5677  set, and exit. This mode is disabled while reading profiles.
5678 5678  .RE
5679 5679  
5680 5680  .sp
5681 5681  .ne 2
5682 5682  .na
5683 5683  \fB\fB-f\fR\fR
5684 5684  .ad
5685 5685  .sp .6
5686 5686  .RS 4n
5687 5687  Disables file name generation.
5688 5688  .RE
5689 5689  
5690 5690  .sp
5691 5691  .ne 2
5692 5692  .na
5693 5693  \fB\fB-G\fR\fR
5694 5694  .ad
5695 5695  .sp .6
5696 5696  .RS 4n
5697 5697  Causes the pattern \fB**\fR by itself to match files and zero or more
5698 5698  directories and subdirectories when used for file name generation. If followed
5699 5699  by a \fB/\fR only directories and subdirectories are matched.
5700 5700  .RE
5701 5701  
5702 5702  .sp
5703 5703  .ne 2
5704 5704  .na
5705 5705  \fB\fB-h\fR\fR
5706 5706  .ad
5707 5707  .sp .6
5708 5708  .RS 4n
5709 5709  Each command becomes a tracked alias when first encountered.
5710 5710  .RE
5711 5711  
5712 5712  .sp
5713 5713  .ne 2
5714 5714  .na
5715 5715  \fB\fB-k\fR\fR
5716 5716  .ad
5717 5717  .sp .6
5718 5718  .RS 4n
5719 5719  Obsolete. All variable assignment arguments are placed in the environment for a
5720 5720  command, not just those that precede the command name.
5721 5721  .RE
5722 5722  
5723 5723  .sp
5724 5724  .ne 2
5725 5725  .na
5726 5726  \fB\fB-m\fR\fR
5727 5727  .ad
5728 5728  .sp .6
5729 5729  .RS 4n
5730 5730  Background jobs run in a separate process group and a line prints upon
5731 5731  completion. The exit status of background jobs is reported in a completion
5732 5732  message. On systems with job control, this option is turned on automatically
5733 5733  for interactive shells.
5734 5734  .RE
5735 5735  
5736 5736  .sp
5737 5737  .ne 2
5738 5738  .na
5739 5739  \fB\fB-n\fR\fR
5740 5740  .ad
5741 5741  .sp .6
5742 5742  .RS 4n
5743 5743  Read commands and check them for syntax errors, but do not execute them.
5744 5744  Ignored for interactive shells.
5745 5745  .RE
5746 5746  
5747 5747  .sp
5748 5748  .ne 2
5749 5749  .na
5750 5750  \fB\fB-o\fR\fR
5751 5751  .ad
5752 5752  .sp .6
5753 5753  .RS 4n
5754 5754  If no option name is supplied, the list of options and their current settings
5755 5755  are written to standard output. When invoked with a \fB+\fR, the options are
5756 5756  written in a format that can be input again to the shell to restore the
5757 5757  settings. This option can be repeated to enable or disable multiple options.
5758 5758  .sp
5759 5759  The following argument can be one of the following option names:
5760 5760  .sp
5761 5761  .ne 2
5762 5762  .na
5763 5763  \fB\fBallexport\fR\fR
5764 5764  .ad
5765 5765  .sp .6
5766 5766  .RS 4n
5767 5767  Same as \fB-a\fR.
5768 5768  .RE
5769 5769  
5770 5770  .sp
5771 5771  .ne 2
5772 5772  .na
5773 5773  \fB\fBbgnice\fR\fR
5774 5774  .ad
5775 5775  .sp .6
5776 5776  .RS 4n
5777 5777  All background jobs are run at a lower priority. This is the default mode.
5778 5778  .RE
5779 5779  
5780 5780  .sp
5781 5781  .ne 2
5782 5782  .na
5783 5783  \fB\fBbraceexpand\fR\fR
5784 5784  .ad
5785 5785  .sp .6
5786 5786  .RS 4n
5787 5787  Same as \fB-\fRB.
5788 5788  .RE
5789 5789  
5790 5790  .sp
5791 5791  .ne 2
5792 5792  .na
5793 5793  \fB\fBemacs\fR\fR
5794 5794  .ad
5795 5795  .sp .6
5796 5796  .RS 4n
5797 5797  Puts you in an \fBemacs\fR style inline editor for command entry.
5798 5798  .RE
5799 5799  
5800 5800  .sp
5801 5801  .ne 2
5802 5802  .na
5803 5803  \fB\fBerrexit\fR\fR
5804 5804  .ad
5805 5805  .sp .6
5806 5806  .RS 4n
5807 5807  Same as \fB-e\fR.
5808 5808  .RE
5809 5809  
5810 5810  .sp
5811 5811  .ne 2
5812 5812  .na
5813 5813  \fB\fBglobstar\fR\fR
5814 5814  .ad
5815 5815  .sp .6
5816 5816  .RS 4n
5817 5817  Same as \fB-G\fR.
5818 5818  .RE
5819 5819  
5820 5820  .sp
5821 5821  .ne 2
5822 5822  .na
5823 5823  \fB\fBgmacs\fR\fR
5824 5824  .ad
5825 5825  .sp .6
5826 5826  .RS 4n
5827 5827  Puts you in a \fBgmacs\fR style inline editor for command entry.
5828 5828  .RE
5829 5829  
5830 5830  .sp
5831 5831  .ne 2
5832 5832  .na
5833 5833  \fB\fBignoreeof\fR\fR
5834 5834  .ad
5835 5835  .sp .6
5836 5836  .RS 4n
5837 5837  The shell does not exit on end-of-file. The command \fBexit\fR must be used.
5838 5838  .RE
5839 5839  
5840 5840  .sp
5841 5841  .ne 2
5842 5842  .na
5843 5843  \fB\fBkeyword\fR\fR
5844 5844  .ad
5845 5845  .sp .6
5846 5846  .RS 4n
5847 5847  Same as \fB-k\fR.
5848 5848  .RE
5849 5849  
5850 5850  .sp
5851 5851  .ne 2
5852 5852  .na
5853 5853  \fB\fBmarkdirs\fR\fR
5854 5854  .ad
5855 5855  .sp .6
5856 5856  .RS 4n
5857 5857  All directory names resulting from file name generation have a trailing /
5858 5858  appended.
5859 5859  .RE
5860 5860  
5861 5861  .sp
5862 5862  .ne 2
5863 5863  .na
5864 5864  \fB\fBmonitor\fR\fR
5865 5865  .ad
5866 5866  .sp .6
5867 5867  .RS 4n
5868 5868  Same as \fB-m\fR.
5869 5869  .RE
5870 5870  
5871 5871  .sp
5872 5872  .ne 2
5873 5873  .na
5874 5874  \fB\fBmultiline\fR\fR
5875 5875  .ad
5876 5876  .sp .6
5877 5877  .RS 4n
5878 5878  The built-in editors use multiple lines on the screen for lines that are longer
5879 5879  than the width of the screen. This might not work for all terminals.
5880 5880  .RE
5881 5881  
5882 5882  .sp
5883 5883  .ne 2
5884 5884  .na
5885 5885  \fB\fBnoclobber\fR\fR
5886 5886  .ad
5887 5887  .sp .6
5888 5888  .RS 4n
5889 5889  Same as \fB-C\fR.
5890 5890  .RE
5891 5891  
5892 5892  .sp
5893 5893  .ne 2
5894 5894  .na
5895 5895  \fB\fBnoexec\fR\fR
5896 5896  .ad
5897 5897  .sp .6
5898 5898  .RS 4n
5899 5899  Same as \fB-n\fR.
5900 5900  .RE
5901 5901  
5902 5902  .sp
5903 5903  .ne 2
5904 5904  .na
5905 5905  \fB\fBnoglob\fR\fR
5906 5906  .ad
5907 5907  .sp .6
5908 5908  .RS 4n
5909 5909  Same as \fB-f\fR.
5910 5910  .RE
5911 5911  
5912 5912  .sp
5913 5913  .ne 2
5914 5914  .na
5915 5915  \fB\fBnolog\fR\fR
5916 5916  .ad
5917 5917  .sp .6
5918 5918  .RS 4n
5919 5919  Do not save function definitions in the history file.
5920 5920  .RE
5921 5921  
5922 5922  .sp
5923 5923  .ne 2
5924 5924  .na
5925 5925  \fB\fBnotify\fR\fR
5926 5926  .ad
5927 5927  .sp .6
5928 5928  .RS 4n
5929 5929  Same as \fB-b\fR.
5930 5930  .RE
5931 5931  
5932 5932  .sp
5933 5933  .ne 2
5934 5934  .na
5935 5935  \fB\fBnounset\fR\fR
5936 5936  .ad
5937 5937  .sp .6
5938 5938  .RS 4n
5939 5939  Same as \fB-u\fR.
5940 5940  .RE
5941 5941  
5942 5942  .sp
5943 5943  .ne 2
5944 5944  .na
5945 5945  \fB\fBpipefail\fR\fR
5946 5946  .ad
5947 5947  .sp .6
5948 5948  .RS 4n
5949 5949  A pipeline does not complete until all components of the pipeline have
5950 5950  completed, and the return value is the value of the last \fBnon-zero\fR command
5951 5951  to fail or zero if no command has failed.
5952 5952  .RE
5953 5953  
5954 5954  .sp
5955 5955  .ne 2
5956 5956  .na
5957 5957  \fB\fBprivileged\fR\fR
5958 5958  .ad
5959 5959  .sp .6
5960 5960  .RS 4n
5961 5961  Same as \fB-p\fR.
5962 5962  .RE
5963 5963  
5964 5964  .sp
5965 5965  .ne 2
5966 5966  .na
5967 5967  \fB\fBshowme\fR\fR
5968 5968  .ad
5969 5969  .sp .6
5970 5970  .RS 4n
5971 5971  When enabled, simple commands or pipelines preceded by a a semicolon (\fB;\fR)
5972 5972  is displayed as if the \fBxtrace\fR option were enabled but is not executed.
5973 5973  Otherwise, the leading \fB;\fR is ignored.
5974 5974  .RE
5975 5975  
5976 5976  .sp
5977 5977  .ne 2
5978 5978  .na
5979 5979  \fB\fBtrackall\fR\fR
5980 5980  .ad
5981 5981  .sp .6
5982 5982  .RS 4n
5983 5983  Same as \fB-h\fR.
5984 5984  .RE
5985 5985  
5986 5986  .sp
5987 5987  .ne 2
5988 5988  .na
5989 5989  \fB\fBverbose\fR\fR
5990 5990  .ad
5991 5991  .sp .6
5992 5992  .RS 4n
5993 5993  Same as \fB-v\fR.
5994 5994  .RE
5995 5995  
5996 5996  .sp
5997 5997  .ne 2
5998 5998  .na
5999 5999  \fB\fBvi\fR\fR
6000 6000  .ad
6001 6001  .sp .6
6002 6002  .RS 4n
6003 6003  Puts you in insert mode of a \fBvi\fR style inline editor until you hit the
6004 6004  escape character 033. This puts you in control mode. A return sends the line.
6005 6005  .RE
6006 6006  
6007 6007  .sp
6008 6008  .ne 2
6009 6009  .na
6010 6010  \fB\fBviraw\fR\fR
6011 6011  .ad
6012 6012  .sp .6
6013 6013  .RS 4n
6014 6014  Each character is processed as it is typed in \fBvi\fR mode.
6015 6015  .RE
6016 6016  
6017 6017  .sp
6018 6018  .ne 2
6019 6019  .na
6020 6020  \fB\fBxtrace\fR\fR
6021 6021  .ad
6022 6022  .sp .6
6023 6023  .RS 4n
6024 6024  Same as \fB-x\fR.
6025 6025  .sp
6026 6026  If no option name is supplied, the current options settings are printed.
6027 6027  .RE
6028 6028  
6029 6029  .RE
6030 6030  
6031 6031  .sp
6032 6032  .ne 2
6033 6033  .na
6034 6034  \fB\fB-p\fR\fR
6035 6035  .ad
6036 6036  .sp .6
6037 6037  .RS 4n
6038 6038  Disables processing of the \fB$HOME/.profile\fR file and uses the file
6039 6039  \fB/etc/suid_profile\fR instead of the \fBENV\fR file. This mode is on whenever
6040 6040  the effective \fBuid\fR (\fBgid\fR) is not equal to the real \fBuid\fR
6041 6041  (\fBgid\fR). Turning this off causes the effective \fBuid\fR and \fBgid\fR to
6042 6042  be set to the real \fBuid\fR and \fBgid\fR.
6043 6043  .RE
6044 6044  
6045 6045  .sp
6046 6046  .ne 2
6047 6047  .na
6048 6048  \fB\fB-r\fR\fR
6049 6049  .ad
6050 6050  .sp .6
6051 6051  .RS 4n
6052 6052  Enables the restricted shell. This option cannot be unset once set.
6053 6053  .RE
6054 6054  
6055 6055  .sp
6056 6056  .ne 2
6057 6057  .na
6058 6058  \fB\fB-s\fR\fR
6059 6059  .ad
6060 6060  .sp .6
6061 6061  .RS 4n
6062 6062  Sort the positional parameters lexicographically.
6063 6063  .RE
6064 6064  
6065 6065  .sp
6066 6066  .ne 2
6067 6067  .na
6068 6068  \fB\fB-t\fR\fR
6069 6069  .ad
6070 6070  .sp .6
6071 6071  .RS 4n
6072 6072  Obsolete. Exit after reading and executing one command.
6073 6073  .RE
6074 6074  
6075 6075  .sp
6076 6076  .ne 2
6077 6077  .na
6078 6078  \fB\fB-u\fR\fR
6079 6079  .ad
6080 6080  .sp .6
6081 6081  .RS 4n
6082 6082  Treat \fBunset\fR parameters as an error when substituting.
6083 6083  .RE
6084 6084  
6085 6085  .sp
6086 6086  .ne 2
6087 6087  .na
6088 6088  \fB\fB-v\fR\fR
6089 6089  .ad
6090 6090  .sp .6
6091 6091  .RS 4n
6092 6092  Print shell input lines as they are read.
6093 6093  .RE
6094 6094  
6095 6095  .sp
6096 6096  .ne 2
6097 6097  .na
6098 6098  \fB\fB-x\fR\fR
6099 6099  .ad
6100 6100  .sp .6
6101 6101  .RS 4n
6102 6102  Print commands and their arguments as they are executed.
6103 6103  .RE
6104 6104  
6105 6105  .sp
6106 6106  .ne 2
6107 6107  .na
6108 6108  \fB\fB--\fR\fR
6109 6109  .ad
6110 6110  .sp .6
6111 6111  .RS 4n
6112 6112  Do not change any of the options. This is useful in setting \fB$1\fR to a value
6113 6113  beginning with \fB-\fR. If no arguments follow this option then the positional
6114 6114  parameters are unset.
6115 6115  .RE
6116 6116  
6117 6117  As an obsolete feature, if the first \fIarg\fR is - then the \fB-x\fR and
6118 6118  \fB-v\fR options are turned off and the next \fIarg\fR is treated as the first
6119 6119  argument. Using \fB+\fR rather than \fB-\fR causes these options to be turned
6120 6120  off. These options can also be used upon invocation of the shell. The current
6121 6121  set of options can be found in \fB$-\fR. Unless \fB-A\fR is specified, the
6122 6122  remaining arguments are positional parameters and are assigned, in order, to
6123 6123  \fB$1 $2 \&....\fR If no arguments are specified, then the names and values of
6124 6124  all variables are printed on the standard output.
6125 6125  .RE
6126 6126  
6127 6127  .sp
6128 6128  .ne 2
6129 6129  .na
6130 6130  \fB\fB+shift\fR \fB[\fR\fIn\fR\fB]\fR\fR
6131 6131  .ad
6132 6132  .sp .6
6133 6133  .RS 4n
6134 6134  The positional parameters from \fB$\fR\fIn\fR\fB+1 ...\fR are renamed
6135 6135  \fB$1 ...\fR, the default \fIn\fR is \fB1\fR. The parameter \fIn\fR can be any
6136 6136  arithmetic expression that evaluates to a non-negative number less than or
6137 6137  equal to \fB$#\fR.
6138 6138  .RE
6139 6139  
6140 6140  .sp
6141 6141  .ne 2
6142 6142  .na
6143 6143  \fB\fBsleep\fR \fIseconds\fR\fR
6144 6144  .ad
6145 6145  .sp .6
6146 6146  .RS 4n
6147 6147  Suspends execution for the number of decimal seconds or fractions of a second
6148 6148  specified by \fIseconds\fR.
6149 6149  .RE
6150 6150  
6151 6151  .sp
6152 6152  .ne 2
6153 6153  .na
6154 6154  \fB\fB+trap\fR \fB-p\fR \fB[\fR\fIaction\fR\fB]\fR
6155 6155  \fB[\fR\fIsig\fR\fB] ...\fR\fR
6156 6156  .ad
6157 6157  .sp .6
6158 6158  .RS 4n
6159 6159  The \fB-p\fR option causes the trap action associated with each trap as
6160 6160  specified by the arguments to be printed with appropriate quoting. Otherwise,
6161 6161  \fIaction\fR is processed as if it were an argument to \fBeval\fR when the
6162 6162  shell receives signal(s) \fIsig\fR. Each \fIsig\fR can be specified as a number
6163 6163  or as the name of the signal. Trap commands are executed in order of signal
6164 6164  number. Any attempt to set a trap on a signal that was ignored on entry to the
6165 6165  current shell is ineffective. If \fIaction\fR is omitted and the first
6166 6166  \fIsig\fR is a number, or if \fIaction\fR is \fB-\fR, then the trap(s) for each
6167 6167  \fIsig\fR are reset to their original values. If \fIaction\fR is the null
6168 6168  string then this signal is ignored by the shell and by the commands it invokes.
6169 6169  If \fIsig\fR is \fBERR\fR then \fIaction\fR is executed whenever a command has
6170 6170  a \fBnon-zero\fR exit status. If \fIsig\fR is \fBDEBUG\fR then \fIaction\fR is
6171 6171  executed before each command. The variable \fB\&.sh.command\fR contains the
6172 6172  contents of the current command line when \fIaction\fR is running. If \fIsig\fR
6173 6173  is \fB0\fR or \fBEXIT\fR and the trap statement is executed inside the body of
6174 6174  a function defined with the \fBfunction\fR \fIname\fR syntax, then the command
6175 6175  \fIaction\fR is executed after the function completes. If \fIsig\fR is \fB0\fR
6176 6176  or \fBEXIT\fR for a trap set outside any function then the command \fIaction\fR
6177 6177  is executed on exit from the shell. If \fIsig\fR is \fBKEYBD\fR, then
6178 6178  \fIaction\fR is executed whenever a key is read while in \fBemacs\fR,
6179 6179  \fBgmacs\fR, or \fBvi\fR mode. The \fBtrap\fR command with no arguments prints
6180 6180  a list of commands associated with each signal number.
6181 6181  .RE
6182 6182  
6183 6183  .sp
6184 6184  .ne 2
6185 6185  .na
6186 6186  \fB\fBtrue\fR\fR
6187 6187  .ad
6188 6188  .sp .6
6189 6189  .RS 4n
6190 6190  Does nothing, and exits \fB0\fR. Used with while for infinite loops.
6191 6191  .RE
6192 6192  
6193 6193  .sp
6194 6194  .ne 2
6195 6195  .na
6196 6196  \fB\fB++typeset [\(+-AHflabnprtux ] [ \(+-EFLRZi[\fR\fIn\fR\fB] ] [\fR
6197 6197  \fIvname\fR\fB[=\fR\fIvalue\fR \fB] ]\fR\fR
6198 6198  .ad
6199 6199  .sp .6
6200 6200  .RS 4n
6201 6201  Sets attributes and values for shell variables and functions. When invoked
6202 6202  inside a function defined with the \fBfunction\fR \fIname\fR syntax, a new
6203 6203  instance of the variable \fIvname\fR is created, and the variable's value and
6204 6204  type are restored when the function completes.
6205 6205  .sp
6206 6206  Using \fB+\fR rather than \fB-\fR causes these options to be turned off. If no
6207 6207  \fIvname\fR arguments are specified, a list of \fIvname\fRs (and optionally the
6208 6208  \fIvalue\fRs) of the variables is printed. Using \fB+\fR rather than \fB-\fR
6209 6209  keeps the values from being printed.) The \fB-p\fR option causes \fBtypeset\fR
6210 6210  followed by the option letters to be printed before each name rather than the
6211 6211  names of the options. If any option other than \fB-p\fR is specified, only
6212 6212  those variables which have all of the specified options are printed. Otherwise,
6213 6213  the \fIvname\fRs and \fIattributes\fR of all variables that have attributes are
6214 6214  printed.
6215 6215  .sp
6216 6216  The following list of attributes can be specified:
6217 6217  .sp
6218 6218  .ne 2
6219 6219  .na
6220 6220  \fB\fB-a\fR\fR
6221 6221  .ad
6222 6222  .RS 6n
6223 6223  Declares \fIvname\fR to be an indexed array. This is optional unless except for
6224 6224  compound variable assignments.
6225 6225  .RE
6226 6226  
6227 6227  .sp
6228 6228  .ne 2
6229 6229  .na
6230 6230  \fB\fB-A\fR\fR
6231 6231  .ad
6232 6232  .RS 6n
6233 6233  Declares \fIvname\fR to be an associative array. Sub-scripts are strings rather
6234 6234  than arithmetic expressions.
6235 6235  .RE
6236 6236  
6237 6237  .sp
6238 6238  .ne 2
6239 6239  .na
6240 6240  \fB\fB-b\fR\fR
6241 6241  .ad
6242 6242  .RS 6n
6243 6243  The variable can hold any number of bytes of data. The data can be text or
6244 6244  binary. The value is represented by the \fBbase64\fR encoding of the data. If
6245 6245  \fB-Z\fR is also specified, the size in bytes of the data in the buffer is
6246 6246  determined by the size associated with the \fB-Z\fR. If the \fBbase64\fR string
6247 6247  assigned results in more data, it is truncated. Otherwise, it is filled with
6248 6248  bytes whose value is zero. The \fBprintf\fR format \fB%B\fR can be used to
6249 6249  output the actual data in this buffer instead of the \fBbase64\fR encoding of
6250 6250  the data.
6251 6251  .RE
6252 6252  
6253 6253  .sp
6254 6254  .ne 2
6255 6255  .na
6256 6256  \fB\fB-E\fR\fR
6257 6257  .ad
6258 6258  .RS 6n
6259 6259  Declares \fIvname\fR to be a double precision floating point number. If \fIn\fR
6260 6260  is \fBnon-zero\fR, it defines the number of significant figures that are used
6261 6261  when expanding \fIvname\fR. Otherwise, ten significant figures is used.
6262 6262  .RE
6263 6263  
6264 6264  .sp
6265 6265  .ne 2
6266 6266  .na
6267 6267  \fB\fB-f\fR\fR
6268 6268  .ad
6269 6269  .RS 6n
6270 6270  The names refer to function names rather than variable names. No assignments
6271 6271  can be made and the only other valid options are \fB-t\fR, \fB-u\fR, and
6272 6272  \fB-x.\fR The \fB-t\fR option turns on execution tracing for this function. The
6273 6273  \fB-u\fR option causes this function to be marked undefined. The \fBFPATH\fR
6274 6274  variable is searched to find the function definition when the function is
6275 6275  referenced. If no options other than \fB-f\fR is specified, then the function
6276 6276  definition is displayed on standard output. If \fB+f\fR is specified, then a
6277 6277  line containing the function name followed by a shell comment containing the
6278 6278  line number and path name of the file where this function was defined, if any,
6279 6279  is displayed.
6280 6280  .sp
6281 6281  The \fB-i\fR attribute cannot be specified with \fB-f\fR.
6282 6282  .RE
6283 6283  
6284 6284  .sp
6285 6285  .ne 2
6286 6286  .na
6287 6287  \fB\fB-F\fR\fR
6288 6288  .ad
6289 6289  .RS 6n
6290 6290  Declares \fIvname\fR to be a double precision floating point number. If \fIn\fR
6291 6291  is \fBnon-zero\fR, it defines the number of places after the decimal point that
6292 6292  are used when expanding \fIvname\fR. Otherwise ten places after the decimal
6293 6293  point is used.
6294 6294  .RE
6295 6295  
6296 6296  .sp
6297 6297  .ne 2
6298 6298  .na
6299 6299  \fB\fB-H\fR\fR
6300 6300  .ad
6301 6301  .RS 6n
6302 6302  This option provides UNIX to hostname file mapping on non-UNIX machines.
6303 6303  .RE
6304 6304  
6305 6305  .sp
6306 6306  .ne 2
6307 6307  .na
6308 6308  \fB\fB-i\fR\fR
6309 6309  .ad
6310 6310  .RS 6n
6311 6311  Declares \fIvname\fR to be represented internally as integer. The right hand
6312 6312  side of an assignment is evaluated as an arithmetic expression when assigning
6313 6313  to an integer. If \fIn\fR is \fBnon-zero\fR, it defines the output arithmetic
6314 6314  base, otherwise the output base is ten.
6315 6315  .sp
6316 6316  The \fB-i\fR attribute cannot be specified along with \fB-R\fR, \fB-L\fR,
6317 6317  \fB-Z\fR, or \fB-f\fR.
6318 6318  .RE
6319 6319  
6320 6320  .sp
6321 6321  .ne 2
6322 6322  .na
6323 6323  \fB\fB-l\fR\fR
6324 6324  .ad
6325 6325  .RS 6n
6326 6326  All uppercase characters are converted to lowercase. The uppercase option,
6327 6327  \fB-u\fR, is turned off.
6328 6328  .RE
6329 6329  
6330 6330  .sp
6331 6331  .ne 2
6332 6332  .na
6333 6333  \fB\fB-L\fR\fR
6334 6334  .ad
6335 6335  .RS 6n
6336 6336  Left justify and remove leading blanks from \fIvalue\fR. If \fIn\fR is
6337 6337  \fBnon-zero\fR, it defines the width of the field, otherwise it is determined
6338 6338  by the width of the value of first assignment. When the variable is assigned
6339 6339  to, it is filled on the right with blanks or truncated, if necessary, to fit
6340 6340  into the field. The \fB-R\fR option is turned off.
6341 6341  .sp
6342 6342  The \fB-i\fR attribute cannot be specified with \fB-L\fR.
6343 6343  .RE
6344 6344  
6345 6345  .sp
6346 6346  .ne 2
6347 6347  .na
6348 6348  \fB\fB-n\fR\fR
6349 6349  .ad
6350 6350  .RS 6n
6351 6351  Declares \fIvname\fR to be a reference to the variable whose name is defined by
6352 6352  the value of variable \fIvname\fR. This is usually used to reference a variable
6353 6353  inside a function whose name has been passed as an argument.
6354 6354  .RE
6355 6355  
6356 6356  .sp
6357 6357  .ne 2
6358 6358  .na
6359 6359  \fB\fB-R\fR\fR
6360 6360  .ad
6361 6361  .RS 6n
6362 6362  Right justify and fill with leading blanks. If \fIn\fR is \fBnon-zero\fR, it
6363 6363  defines the width of the field, otherwise it is determined by the width of the
6364 6364  value of first assignment. The field is left filled with blanks or truncated
6365 6365  from the end if the variable is reassigned. The \fB-L\fR option is turned off.
6366 6366  .sp
6367 6367  The \fB-i\fR attribute cannot be specified with \fB-R\fR.
6368 6368  .RE
6369 6369  
6370 6370  .sp
6371 6371  .ne 2
6372 6372  .na
6373 6373  \fB\fB-r\fR\fR
6374 6374  .ad
6375 6375  .RS 6n
6376 6376  The specified \fIvname\fRs are marked read-only and these names cannot be
6377 6377  changed by subsequent assignment.
6378 6378  .RE
6379 6379  
6380 6380  .sp
6381 6381  .ne 2
6382 6382  .na
6383 6383  \fB\fB-t\fR\fR
6384 6384  .ad
6385 6385  .RS 6n
6386 6386  Tags the variables. Tags are user definable and have no special meaning to the
6387 6387  shell.
6388 6388  .RE
6389 6389  
6390 6390  .sp
6391 6391  .ne 2
6392 6392  .na
6393 6393  \fB\fB-u\fR\fR
6394 6394  .ad
6395 6395  .RS 6n
6396 6396  All lowercase characters are converted to uppercase. The lowercase option,
6397 6397  \fB-l\fR, is turned off.
6398 6398  .RE
6399 6399  
6400 6400  .sp
6401 6401  .ne 2
6402 6402  .na
6403 6403  \fB\fB-x\fR\fR
6404 6404  .ad
6405 6405  .RS 6n
6406 6406  The specified \fIvname\fRs are marked for automatic export to the environment
6407 6407  of subsequently-executed commands. Variables whose names contain a . cannot be
6408 6408  exported.
6409 6409  .RE
6410 6410  
6411 6411  .sp
6412 6412  .ne 2
6413 6413  .na
6414 6414  \fB\fB-Z\fR\fR
6415 6415  .ad
6416 6416  .RS 6n
6417 6417  Right justify and fill with leading zeros if the first non-blank character is a
6418 6418  digit and the \fB-L\fR option has not been set. Remove leading zeros if the
6419 6419  \fB-L\fR option is also set. If \fIn\fR is \fBnon-zero\fR, it defines the width
6420 6420  of the field, otherwise it is determined by the width of the value of first
6421 6421  assignment.
6422 6422  .sp
6423 6423  The \fB-i\fR attribute cannot be specified with \fB-Z\fR.
6424 6424  .RE
6425 6425  
6426 6426  .RE
6427 6427  
6428 6428  .sp
6429 6429  .ne 2
6430 6430  .na
6431 6431  \fB\fBulimit [\fR\fB-HSacdfmnpstv\fR\fB] [\fR \fIlimit\fR\fB]\fR\fR
6432 6432  .ad
6433 6433  .sp .6
6434 6434  .RS 4n
6435 6435  Set or display a resource limit. Many systems do not support one or more of
6436 6436  these limits. The limit for a specified resource is set when \fIlimit\fR is
6437 6437  specified. The value of \fIlimit\fR can be a number in the unit specified with
6438 6438  each resource, or the value unlimited. When more than one resource is
6439 6439  specified, then the limit name and unit is printed before the value.
6440 6440  .sp
6441 6441  If no option is specified, \fB-f\fR is assumed.
6442 6442  .sp
6443 6443  The following are the available resource limits:
6444 6444  .sp
6445 6445  .ne 2
6446 6446  .na
6447 6447  \fB\fB-a\fR\fR
6448 6448  .ad
6449 6449  .RS 6n
6450 6450  Lists all of the current resource limits.
6451 6451  .RE
6452 6452  
6453 6453  .sp
6454 6454  .ne 2
6455 6455  .na
6456 6456  \fB\fB-c\fR\fR
6457 6457  .ad
6458 6458  .RS 6n
6459 6459  The number of 512-byte blocks on the size of core dumps.
6460 6460  .RE
6461 6461  
6462 6462  .sp
6463 6463  .ne 2
6464 6464  .na
6465 6465  \fB\fB-d\fR\fR
6466 6466  .ad
6467 6467  .RS 6n
6468 6468  The number of Kbytes on the size of the data area.
6469 6469  .RE
6470 6470  
6471 6471  .sp
6472 6472  .ne 2
6473 6473  .na
6474 6474  \fB\fB-f\fR\fR
6475 6475  .ad
6476 6476  .RS 6n
6477 6477  The number of 512-byte blocks on files that can be written by the current
6478 6478  process or by child processes (files of any size can be read).
6479 6479  .RE
6480 6480  
6481 6481  .sp
6482 6482  .ne 2
6483 6483  .na
6484 6484  \fB\fB-H\fR\fR
6485 6485  .ad
6486 6486  .RS 6n
6487 6487  Specifies a hard limit for the specified resource.
6488 6488  .sp
6489 6489  A hard limit cannot be increased once it is set.
6490 6490  .sp
6491 6491  If neither the \fB-H\fR nor \fB-S\fR option is specified, the limit applies to
6492 6492  both. The current resource limit is printed when \fIlimit\fR is omitted. In
6493 6493  this case, the soft limit is printed unless \fB-H\fR is specified.
6494 6494  .RE
6495 6495  
6496 6496  .sp
6497 6497  .ne 2
6498 6498  .na
6499 6499  \fB\fB-m\fR\fR
6500 6500  .ad
6501 6501  .RS 6n
6502 6502  The number of Kbytes on the size of physical memory.
6503 6503  .RE
6504 6504  
6505 6505  .sp
6506 6506  .ne 2
6507 6507  .na
6508 6508  \fB\fB-n\fR\fR
6509 6509  .ad
6510 6510  .RS 6n
6511 6511  The number of file descriptors plus 1.
6512 6512  .RE
6513 6513  
6514 6514  .sp
6515 6515  .ne 2
6516 6516  .na
6517 6517  \fB\fB-p\fR\fR
6518 6518  .ad
6519 6519  .RS 6n
6520 6520  The number of 512-byte blocks for pipe buffering.
6521 6521  .RE
6522 6522  
6523 6523  .sp
6524 6524  .ne 2
6525 6525  .na
6526 6526  \fB\fB-s\fR\fR
6527 6527  .ad
6528 6528  .RS 6n
6529 6529  The number of Kbytes on the size of the stack area.
6530 6530  .RE
6531 6531  
6532 6532  .sp
6533 6533  .ne 2
6534 6534  .na
6535 6535  \fB\fB-S\fR\fR
6536 6536  .ad
6537 6537  .RS 6n
6538 6538  Specifies a soft limit for the specified resource.
6539 6539  .sp
6540 6540  A soft limit can be increased up to the value of the hard limit.
6541 6541  .sp
6542 6542  If neither the \fB-H\fR nor \fB-S\fR option is specified, the limit applies to
6543 6543  both. The current resource limit is printed when \fIlimit\fR is omitted. In
6544 6544  this case, the soft limit is printed unless \fB-H\fR is specified.
6545 6545  .RE
6546 6546  
6547 6547  .sp
6548 6548  .ne 2
6549 6549  .na
6550 6550  \fB\fB-t\fR\fR
6551 6551  .ad
6552 6552  .RS 6n
6553 6553  The number of CPU seconds to be used by each process.
6554 6554  .RE
6555 6555  
6556 6556  .sp
6557 6557  .ne 2
6558 6558  .na
6559 6559  \fB\fB-v\fR\fR
6560 6560  .ad
6561 6561  .RS 6n
6562 6562  The number of Kbytes for virtual memory.
6563 6563  .RE
6564 6564  
6565 6565  .RE
6566 6566  
6567 6567  .sp
6568 6568  .ne 2
6569 6569  .na
6570 6570  \fB\fBumask\fR \fB[\fR\fB-S\fR\fB]\fR\fB[\fR\fImask\fR\fB]\fR\fR
6571 6571  .ad
6572 6572  .sp .6
6573 6573  .RS 4n
6574 6574  The user file-creation mask is set to \fImask\fR. \fImask\fR can either be an
6575 6575  octal number or a symbolic value as described in \fBchmod\fR(1).
6576 6576  .sp
6577 6577  If a symbolic value is specified, the new \fBumask\fR value is the complement
6578 6578  of the result of applying \fImask\fR to the complement of the previous
6579 6579  \fBumask\fR value. If \fImask\fR is omitted, the current value of the mask is
6580 6580  printed. The \fB-S\fR option causes the mode to be printed as a symbolic value.
6581 6581  Otherwise, the mask is printed in octal.
6582 6582  .sp
6583 6583  See \fBumask\fR(2)
6584 6584  .RE
6585 6585  
6586 6586  .sp
6587 6587  .ne 2
6588 6588  .na
6589 6589  \fB\fB+unalias\fR \fB[\fR\fB-a\fR\fB]\fR \fIname\fR\fR
6590 6590  .ad
6591 6591  .sp .6
6592 6592  .RS 4n
6593 6593  The aliases specified by the list of \fIname\fRs are removed from the alias
6594 6594  list. The \fB-a\fR option causes all the aliases to be unset.
6595 6595  .RE
6596 6596  
6597 6597  .sp
6598 6598  .ne 2
6599 6599  .na
6600 6600  \fB\fB+unset\fR \fB[\fR\fB-fnv\fR\fB]\fR \fIvname\fR\fR
6601 6601  .ad
6602 6602  .sp .6
6603 6603  .RS 4n
6604 6604  The variables specified by the list of \fIvname\fRs are unassigned, i.e., their
6605 6605  values and attributes are erased. Read-only variables cannot be unset. If the
6606 6606  \fB-f\fR option is set, then the names refer to function names. If the \fB-v\fR
6607 6607  option is set, then the names refer to variable names. The \fB-f\fR option
6608 6608  overrides \fB-v\fR. If \fB-n\fR is set and \fIname\fR is a name reference, then
6609 6609  \fIname\fR is unset rather than the variable that it references. The default is
6610 6610  equivalent to \fB-v\fR. Unsetting \fBLINENO\fR, \fBMAILCHECK\fR, \fBOPTARG\fR,
6611 6611  \fBOPTIND\fR, \fBRANDOM\fR, \fBSECONDS\fR, \fBTMOUT\fR, and \fB_\fR removes
6612 6612  their special meaning even if they are subsequently assigned to.
6613 6613  .RE
6614 6614  
6615 6615  .sp
6616 6616  .ne 2
6617 6617  .na
6618 6618  \fB\fBwait\fR \fB[\fR\fIjob\fR\fB]\fR\fR
6619 6619  .ad
6620 6620  .sp .6
6621 6621  .RS 4n
6622 6622  Wait for the specified job and report its termination status. If \fIjob\fR is
6623 6623  not specified, then all currently active child processes are waited for. The
6624 6624  exit status from this command is that of the last process waited for if
6625 6625  \fIjob\fR is specified; otherwise it is zero. See \fBJobs\fR for a description
6626 6626  of the format of \fIjob\fR.
6627 6627  .RE
6628 6628  
6629 6629  .sp
6630 6630  .ne 2
6631 6631  .na
6632 6632  \fB\fBwhence\fR \fB[\fR\fB-afpv\fR\fB]\fR \fIname ...\fR\fR
6633 6633  .ad
6634 6634  .sp .6
6635 6635  .RS 4n
6636 6636  For each \fIname\fR, indicate how it would be interpreted if used as a command
6637 6637  name. The \fB-v\fR option produces a more verbose report. The \fB-f\fR option
6638 6638  skips the search for functions. The \fB-p\fR option does a path search for
6639 6639  \fIname\fR even if name is an alias, a function, or a reserved word. The
6640 6640  \fB-a\fR option is similar to the -v option but causes all interpretations of
6641 6641  the specified name to be reported.
6642 6642  .RE
6643 6643  
6644 6644  .SS "Invocation"
6645 6645  .sp
6646 6646  .LP
6647 6647  If the shell is invoked by \fBexec\fR(2), and the first character of argument
6648 6648  zero (\fB$0\fR) is \fB-\fR, then the shell is assumed to be a login shell and
6649 6649  commands are read from \fB/etc/profile\fR and then from either .\fBprofile\fR
6650 6650  in the current directory or \fB$HOME/.profile\fR, if either file exists. Next,
6651 6651  for interactive shells, commands are read first from \fB/etc/ksh.kshrc\fR, and
6652 6652  then from the file named by performing parameter expansion, command
6653 6653  substitution, and arithmetic substitution on the value of the environment
6654 6654  variable \fBENV\fR if the file exists. If the \fB-s\fR option is not present
6655 6655  and \fIarg\fR and a file by the name of \fIarg\fR exists, then it reads and
6656 6656  executes this script. Otherwise, if the first \fIarg\fR does not contain a
6657 6657  \fB/\fR, a path search is performed on the first \fIarg\fR to determine the
6658 6658  name of the script to execute. The script \fIarg\fR must have execute
6659 6659  permission and any \fBsetuid\fR and \fBsetgid\fR settings are ignored. If the
6660 6660  script is not found on the path, \fIarg\fR is processed as if it named a
6661 6661  built-in command or function.
6662 6662  .sp
6663 6663  .LP
6664 6664  Commands are then read as described, and the following options are interpreted
6665 6665  by the shell when it is invoked:
6666 6666  .sp
6667 6667  .ne 2
6668 6668  .na
6669 6669  \fB\fB-c\fR\fR
6670 6670  .ad
6671 6671  .RS 15n
6672 6672  If the \fB-c\fR option is present, then commands are read from the first
6673 6673  \fIarg\fR. Any remaining arguments become positional parameters starting at
6674 6674  \fB0\fR.
6675 6675  .RE
6676 6676  
6677 6677  .sp
6678 6678  .ne 2
6679 6679  .na
6680 6680  \fB\fB-D\fR\fR
6681 6681  .ad
6682 6682  .RS 15n
6683 6683  A list of all double quoted strings that are preceded by a \fB$\fR is printed
6684 6684  on standard output and the shell exits. This set of strings is subject to
6685 6685  language translation when the locale is not C or POSIX. No commands are
6686 6686  executed.
6687 6687  .RE
6688 6688  
6689 6689  .sp
6690 6690  .ne 2
6691 6691  .na
6692 6692  \fB\fB-i\fR\fR
6693 6693  .ad
6694 6694  .RS 15n
6695 6695  If the \fB-i\fR option is present or if the shell input and output are attached
6696 6696  to a terminal (as told by \fBtcgetattr\fR(3C), this shell is interactive. In
6697 6697  this case \fBTERM\fR is ignored (so that \fBkill 0\fR does not kill an
6698 6698  interactive shell) and \fBINTR\fR is caught and ignored (so that wait is
6699 6699  interruptible). In all cases, \fBQUIT\fR is ignored by the shell.
6700 6700  .RE
6701 6701  
6702 6702  .sp
6703 6703  .ne 2
6704 6704  .na
6705 6705  \fB\fB-R\fR \fIfilename\fR\fR
6706 6706  .ad
6707 6707  .RS 15n
6708 6708  The \fB-R\fR \fIfilename\fR option is used to generate a cross reference
6709 6709  database that can be used by a separate utility to find definitions and
6710 6710  references for variables and commands.
6711 6711  .RE
6712 6712  
6713 6713  .sp
6714 6714  .ne 2
6715 6715  .na
6716 6716  \fB\fB-r\fR\fR
6717 6717  .ad
6718 6718  .RS 15n
6719 6719  If the \fB-r\fR option is present, the shell is a restricted shell.
6720 6720  .RE
6721 6721  
6722 6722  .sp
6723 6723  .ne 2
6724 6724  .na
6725 6725  \fB\fB-s\fR\fR
6726 6726  .ad
6727 6727  .RS 15n
6728 6728  If the \fB-s\fR option is present or if no arguments remain, then commands are
6729 6729  read from the standard input. Shell output, except for the output of the
6730 6730  \fBSpecial Commands\fR listed, is written to file descriptor 2.
6731 6731  .RE
6732 6732  
6733 6733  .sp
6734 6734  .LP
6735 6735  The remaining options and arguments are described under the \fBset\fR command.
6736 6736  An optional \fB-\fR as the first argument is ignored.
6737 6737  .SS "\fBrksh93\fR Only"
6738 6738  .sp
6739 6739  .LP
6740 6740  \fBrksh93\fR is used to set up login names and execution environments whose
6741 6741  capabilities are more controlled than those of the standard shell.
6742 6742  .sp
6743 6743  .LP
6744 6744  The actions of \fBrksh93\fR are identical to those of \fBksh93\fR, except that
6745 6745  the following are disallowed:
6746 6746  .RS +4
6747 6747  .TP
6748 6748  .ie t \(bu
6749 6749  .el o
6750 6750  Unsetting the restricted option
6751 6751  .RE
6752 6752  .RS +4
6753 6753  .TP
6754 6754  .ie t \(bu
6755 6755  .el o
6756 6756  Changing directory. See \fBcd\fR(1).
6757 6757  .RE
6758 6758  .RS +4
6759 6759  .TP
6760 6760  .ie t \(bu
6761 6761  .el o
6762 6762  Setting or unsetting the value or attributes of \fBSHELL\fR, \fBENV\fR,
6763 6763  \fBFPATH\fR, or \fBPATH\fR
6764 6764  .RE
6765 6765  .RS +4
6766 6766  .TP
6767 6767  .ie t \(bu
6768 6768  .el o
6769 6769  Specifying path or command names containing \fB/\fR,
6770 6770  .RE
6771 6771  .RS +4
6772 6772  .TP
6773 6773  .ie t \(bu
6774 6774  .el o
6775 6775  Redirecting output (\fB>\fR, \fB>\fR\fB|\fR, \fB<>\fR, and \fB>>\fR).
6776 6776  .RE
6777 6777  .RS +4
6778 6778  .TP
6779 6779  .ie t \(bu
6780 6780  .el o
6781 6781  Adding or deleting built-in commands.
6782 6782  .RE
6783 6783  .RS +4
6784 6784  .TP
6785 6785  .ie t \(bu
6786 6786  .el o
6787 6787  Using \fBcommand\fR \fB-p\fR to invoke a command.
6788 6788  .RE
6789 6789  .sp
6790 6790  .LP
6791 6791  These restrictions are enforced after .\fBprofile\fR and the \fBENV\fR files
6792 6792  are interpreted.
6793 6793  .sp
6794 6794  .LP
6795 6795  When a command to be executed is found to be a shell procedure, \fBrksh93\fR
6796 6796  invokes \fBksh93\fR to execute it. Thus, it is possible to provide to the
6797 6797  end-user shell procedures that have access to the full power of the standard
6798 6798  shell, while imposing a limited menu of commands. This scheme assumes that the
6799 6799  end-user does not have write and execute permissions in the same directory. The
6800 6800  net effect of these rules is that the writer of the .\fBprofile\fR has complete
6801 6801  control over user actions, by performing guaranteed setup actions and leaving
6802 6802  the user in an appropriate directory (probably not the login directory). The
6803 6803  system administrator often sets up a directory of commands, for example,
6804 6804  \fB/usr/rbin\fR, that can be safely invoked by \fBrksh\fR.
6805 6805  .SH USAGE
6806 6806  .sp
6807 6807  .LP
6808 6808  See \fBlargefile\fR(5) for the description of the behavior of \fBksh93\fR and
6809 6809  \fBrksh93\fR when encountering files greater than or equal to 2 Gbyte ( 2^31
6810 6810  bytes).
6811 6811  .SH EXIT STATUS
6812 6812  .sp
6813 6813  .LP
6814 6814  The following exit values are returned:
6815 6815  .sp
6816 6816  .ne 2
6817 6817  .na
6818 6818  \fB\fBnon-zero\fR\fR
6819 6819  .ad
6820 6820  .sp .6
6821 6821  .RS 4n
6822 6822  Returns \fBnon-zero\fR when errors, such as syntax errors, are detected by the
6823 6823  shell.
6824 6824  .sp
6825 6825  If the shell is being used non-interactively, then execution of the shell file
6826 6826  is abandoned unless the error occurs inside a sub-shell in which case the
6827 6827  sub-shell is abandoned.
6828 6828  .RE
6829 6829  
6830 6830  .sp
6831 6831  .ne 2
6832 6832  .na
6833 6833  \fB\fIexit status of last command executed\fR\fR
6834 6834  .ad
6835 6835  .sp .6
6836 6836  .RS 4n
6837 6837  Returns the exit status of the last command executed.
6838 6838  .sp
6839 6839  Run time errors detected by the shell are reported by printing the command or
6840 6840  function name and the error condition. If the line number that the error
6841 6841  occurred on is greater than one, then the line number is also printed in square
6842 6842  brackets (\fB[]\fR) after the command or function name.
6843 6843  .sp
6844 6844  See the \fBksh93 exit\fR command for additional details.
6845 6845  .RE
6846 6846  
6847 6847  .SH FILES
6848 6848  .sp
6849 6849  .ne 2
6850 6850  .na
6851 6851  \fB\fB/etc/profile\fR\fR
6852 6852  .ad
6853 6853  .sp .6
6854 6854  .RS 4n
6855 6855  The system initialization file, executed for login shells.
6856 6856  .RE
6857 6857  
6858 6858  .sp
6859 6859  .ne 2
6860 6860  .na
6861 6861  \fB\fB/etc/ksh.kshrc\fR\fR
6862 6862  .ad
6863 6863  .sp .6
6864 6864  .RS 4n
6865 6865  The system wide startup file, executed for interactive shells.
6866 6866  .RE
6867 6867  
6868 6868  .sp
6869 6869  .ne 2
6870 6870  .na
6871 6871  \fB\fB$HOME/.profile\fR\fR
6872 6872  .ad
6873 6873  .sp .6
6874 6874  .RS 4n
6875 6875  The personal initialization file, executed for login shells after
6876 6876  \fB/etc/profile\fR.
6877 6877  .RE
6878 6878  
6879 6879  .sp
6880 6880  .ne 2
6881 6881  .na
6882 6882  \fB\fB$HOME/.kshrc\fR\fR
6883 6883  .ad
6884 6884  .sp .6
6885 6885  .RS 4n
6886 6886  Default personal initialization file, executed after \fB/etc/ksh.kshrc\fR, for
6887 6887  interactive shells when \fBENV\fR is not set.
6888 6888  .RE
6889 6889  
6890 6890  .sp
6891 6891  .ne 2
6892 6892  .na
6893 6893  \fB\fB/etc/suid-profile\fR\fR
6894 6894  .ad
6895 6895  .sp .6
6896 6896  .RS 4n
6897 6897  Alternative initialization file, executed instead of the personal
6898 6898  initialization file when the real and effective user or group id do not match.
6899 6899  .RE
6900 6900  
6901 6901  .sp
6902 6902  .ne 2
6903 6903  .na
6904 6904  \fB\fB/dev/null\fR\fR
6905 6905  .ad
6906 6906  .sp .6
6907 6907  .RS 4n
6908 6908  NULL device.
6909 6909  .RE
6910 6910  
6911 6911  .SH AUTHORS
6912 6912  .sp
6913 6913  .LP
6914 6914  David Korn, \fBdgk@research.att.com\fR
6915 6915  .SH ATTRIBUTES
6916 6916  .sp
6917 6917  .LP
6918 6918  See \fBattributes\fR(5) for descriptions of the following attributes:
6919 6919  .sp
6920 6920  
6921 6921  .sp
6922 6922  .TS
6923 6923  box;
6924 6924  c | c
6925 6925  l | l .
6926 6926  ATTRIBUTE TYPE  ATTRIBUTE VALUE
6927 6927  _
6928 6928  Interface Stability     See below.
6929 6929  .TE
6930 6930  
6931 6931  .sp
6932 6932  .LP
6933 6933  The scripting interface is Uncommitted. The environment variables,
6934 6934  \fB\&.paths\fR feature, and editing modes are Volatile.
6935 6935  .SH SEE ALSO
6936 6936  .sp
6937 6937  .LP
6938 6938  \fBcat\fR(1), \fBcd\fR(1), \fBchmod\fR(1), \fBcut\fR(1), \fBdate\fR(1),
6939 6939  \fBegrep\fR(1), \fBecho\fR(1), \fBegrep\fR(1), \fBenv\fR(1), \fBfgrep\fR(1),
6940 6940  \fBgrep\fR(1), \fBlogin\fR(1), \fBnewgrp\fR(1), \fBpaste\fR(1),
6941 6941  \fBprintf\fR(1), \fBstty\fR(1), \fBtest\fR(1), \fBumask\fR(1), \fBvi\fR(1),
6942 6942  \fBdup\fR(2), \fBexec\fR(2), \fBfork\fR(2), \fBioctl\fR(2), \fBlseek\fR(2),
6943 6943  \fBpathconf\fR(2), \fBpipe\fR(2), \fBsysconf\fR(3C), \fBulimit\fR(2),
6944 6944  \fBumask\fR(2), \fBrand\fR(3C)\fBtcgetattr\fR(3C), \fBwait\fR(3C),
6945 6945  \fBa.out\fR(4), \fBprofile\fR(4), \fBattributes\fR(5), \fBenviron\fR(5),
6946 6946  \fBlargefile\fR(5), \fBstandards\fR(5)
6947 6947  .sp
6948 6948  .LP
6949 6949  Bolsky, Morris I. and Korn, David G., \fIThe New KornShell Command and
6950 6950  Programming Language\fR, Prentice Hall, 1995.
6951 6951  .sp
6952 6952  .LP
6953 6953  \fIPOSIX-Part 2: Shell and Utilities, IEEE Std 1003.2-1992, ISO/IEC 9945-2\fR,
6954 6954  IEEE, 1993.
6955 6955  .SH NOTES
6956 6956  .sp
6957 6957  .LP
6958 6958  \fBksh93\fR scripts should choose shell function names outside the namespace
6959 6959  used by reserved keywords of the ISO C99, C++ and JAVA languages to avoid
6960 6960  collisions with future enhancements to \fBksh93\fR.
6961 6961  .sp
6962 6962  .LP
6963 6963  If a command is executed, and then a command with the same name is installed in
6964 6964  a directory in the search path before the directory where the original command
6965 6965  was found, the shell continues to \fBexec\fR the original command. Use the
6966 6966  \fB-t\fR option of the alias command to correct this situation.
6967 6967  .sp
6968 6968  .LP
6969 6969  Some very old shell scripts contain a caret (\fB^\fR) as a synonym for the pipe
6970 6970  character (\fB|\fR).
6971 6971  .sp
6972 6972  .LP
6973 6973  Using the \fBhist\fR built-in command within a compound command causes the
6974 6974  whole command to disappear from the history file.
6975 6975  .sp
6976 6976  .LP
6977 6977  The built-in command \fB\&.\fR \fIfile\fR reads the whole file before any
6978 6978  commands are executed. \fBalias\fR and \fBunalias\fR commands in the file do
6979 6979  not apply to any commands defined in the file.
6980 6980  .sp
6981 6981  .LP
6982 6982  Traps are not processed while a job is waiting for a foreground process. Thus,
6983 6983  a trap on \fBCHLD\fR is not executed until the foreground job terminates.
6984 6984  .sp
6985 6985  .LP
6986 6986  It is a good idea to leave a space after the comma operator in arithmetic
6987 6987  expressions to prevent the comma from being interpreted as the decimal point
6988 6988  character in certain locales.
6989 6989  .sp
6990 6990  .LP
6991 6991  There might be some restrictions on creating a \fB\&.paths\fR file which is
6992 6992  portable across other operating systems.
6993 6993  .sp
6994 6994  .LP
6995 6995  If the system supports the 64-bit instruction set, \fB/bin/ksh93\fR executes
6996 6996  the 64-bit version of \fBksh93\fR.

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