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Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. 10 .\" This notice shall appear on any product containing this material. 11 .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). 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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 14 .TH HEAD 1 "Mar 4, 2013" 15 .SH NAME 16 head \- display first few lines of files 17 .SH SYNOPSIS 18 .SS "/usr/bin/head" 19 .LP 20 .nf 21 \fB/usr/bin/head\fR [\fB-q\fR] [\fB-v\fR] [\fB-number\fR ] [ \fB-n\fR \fInumber\fR ] [ \fB-c\fR \fInumber\fR] [\fIfilename\fR]... 22 .fi 23 24 .SS "ksh93" 25 .LP 26 .nf 27 \fBhead\fR [\fB-qv\fR] [\fB-n\fR \fIlines\fR] [\fB-c\fR \fIchars\fR] [\fB-s\fR \fIskip\fR] [\fIfilename\fR]... 28 .fi 29 30 .SH DESCRIPTION 31 .SS "/usr/bin/head" 32 .sp 33 .LP 34 The \fBhead\fR utility copies the first \fInumber\fR of lines of each 35 \fIfilename\fR to the standard output. If no \fIfilename\fR is given, 36 \fBhead\fR copies lines from the standard input. The default value of 37 \fInumber\fR is \fB10\fR lines. If \fB-c\fR is specified, \fBhead\fR 38 copies the first \fInumber\fR of bytes of each filename. 39 .sp 40 .LP 41 When more than one file is specified, the start of each file looks like: 42 .sp 43 .in +2 44 .nf 45 \fB==>\fR \fIfilename\fR \fB<==\fR 46 .fi 47 .in -2 48 49 .sp 50 .LP 51 Thus, a common way to display a set of short files, identifying each one, is: 52 .sp 53 .in +2 54 .nf 55 example% \fBhead -9999 filename1 filename2 ...\fR 56 .fi 57 .in -2 58 .sp 59 60 .SS "ksh93" 61 .sp 62 .LP 63 The \fBhead\fR built-in in \fBksh93\fR is associated with the \fB/bin\fR and 64 \fB/usr/bin\fR paths. It is invoked when \fBhead\fR is executed without a 65 pathname prefix and the pathname search finds a \fB/bin/head\fR or 66 \fB/usr/bin/head\fR executable. 67 .sp 68 .LP 69 \fBhead\fR copies one or more input files to standard output, stopping at a 70 designated point for each file or to the end of the file whichever comes first. 71 Copying ends at the point indicated by the options. By default, a header of the 72 form \fB==> filename <==\fR is output before all but the first file but this 73 can be changed with the \fB-q\fR and \fB-v\fR options. If no file is given, or 74 if the file is \fB-\fR, \fBhead\fR copies from standard input starting at the 75 current location. 76 .sp 77 .LP 78 The option argument for \fB-c\fR and \fB-s\fR can optionally be followed by one 79 of the following characters to specify a different unit other than a single 80 byte: 81 .sp 82 .ne 2 83 .na 84 \fB\fBb\fR\fR 85 .ad 86 .RS 5n 87 512 bytes 88 .RE 89 90 .sp 91 .ne 2 92 .na 93 \fB\fBk\fR\fR 94 .ad 95 .RS 5n 96 1-kilobyte 97 .RE 98 99 .sp 100 .ne 2 101 .na 102 \fB\fBm\fR\fR 103 .ad 104 .RS 5n 105 1-megabyte 106 .RE 107 108 .sp 109 .LP 110 For backwards compatibility, \fB-number\fR is equivalent to \fB-n\fR number. 111 .SH OPTIONS 112 .SS "/usr/bin/head" 113 .sp 114 .LP 115 The following options are supported by \fB/usr/bin/head\fR: 116 .sp 117 .ne 2 118 .na 119 \fB\fB-n\fR \fInumber\fR\fR 120 .ad 121 .RS 13n 122 The first \fInumber\fR lines of each input file is copied to standard output. 123 The \fInumber\fR option-argument must be a positive decimal integer. 124 .RE 125 126 .sp 127 .ne 2 128 .na 129 \fB\fB-c\fR \fInumber\fR\fR 130 .ad 131 .RS 13n 132 The first \fInumber\fR bytes of each input file is copied to standard output. 133 The \fInumber\fR option-argument must be a positive decimal integer. Note, 134 output may end in the middle of a character if a file contains multi-byte 135 characters. 136 .RE 137 138 .sp 139 .ne 2 140 .na 141 \fB\fB-\fR\fInumber\fR\fR 142 .ad 143 .RS 13n 144 The \fInumber\fR argument is a positive decimal integer with the same effect as 145 the \fB-n\fR \fInumber\fR option. 146 .RE 147 148 .sp 149 .ne 2 150 .na 151 \fB\FB-q\fR\fR 152 .ad 153 .RS 13n 154 \fBhead\fR will not print a header in between each specified file. 155 .RE 156 157 .sp 158 .ne 2 159 .na 160 \fB\FB-v\fR\fR 161 .ad 162 .RS 13n 163 \fBhead\fR will always print a header in between each specified file. 164 .RE 165 166 .sp 167 .LP 168 If no options are specified, \fBhead\fR acts as if \fB-n\fR \fB10\fR had been 169 specified. 170 .SS "ksh93" 171 .sp 172 .LP 173 The following options are supported by the head built-in command in 174 \fBksh93\fR: 175 .sp 176 .ne 2 177 .na 178 \fB\fB-n\fR\fR 179 .ad 180 .br 181 .na 182 \fB\fB--lines=\fR\fIlines\fR\fR 183 .ad 184 .RS 18n 185 Copy lines from each file. The default value is \fB10\fR. 186 .RE 187 188 .sp 189 .ne 2 190 .na 191 \fB\fB-c\fR\fR 192 .ad 193 .br 194 .na 195 \fB\fB--bytes=\fR\fIchars\fR\fR 196 .ad 197 .RS 18n 198 Copy \fIchars\fR bytes from each file. 199 .RE 200 201 .sp 202 .ne 2 203 .na 204 \fB\fB-q\fR\fR 205 .ad 206 .br 207 .na 208 \fB\fB--quiet|silent\fR\fR 209 .ad 210 .RS 18n 211 Never output filename headers. 212 .RE 213 214 .sp 215 .ne 2 216 .na 217 \fB\fB-s\fR\fR 218 .ad 219 .br 220 .na 221 \fB\fB--skip=\fR\fIskip\fR\fR 222 .ad 223 .RS 18n 224 Skip \fIskip\fR characters or lines from each file before copying. 225 .RE 226 227 .sp 228 .ne 2 229 .na 230 \fB\fB-v\fR\fR 231 .ad 232 .br 233 .na 234 \fB\fB--verbose\fR\fR 235 .ad 236 .RS 18n 237 Always output filename headers. 238 .RE 239 240 .SH OPERANDS 241 .sp 242 .LP 243 The following operand is supported: 244 .sp 245 .ne 2 246 .na 247 \fB\fB\fIfilename\fR\fR\fR 248 .ad 249 .RS 12n 250 A path name of an input file. If no \fIfile\fR operands are specified, the 251 standard input is used. 252 .RE 253 254 .SH USAGE 255 .sp 256 .LP 257 See \fBlargefile\fR(5) for the description of the behavior of \fBhead\fR when 258 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes). 259 .SH EXAMPLES 260 .LP 261 \fBExample 1 \fRWriting the First Ten Lines of All Files 262 .sp 263 .LP 264 The following example writes the first ten lines of all files, except those 265 with a leading period, in the directory: 266 267 .sp 268 .in +2 269 .nf 270 example% \fBhead *\fR 271 .fi 272 .in -2 273 .sp 274 275 .SH ENVIRONMENT VARIABLES 276 .sp 277 .LP 278 See \fBenviron\fR(5) for descriptions of the following environment variables 279 that affect the execution of \fBhead\fR: \fBLANG\fR, \fBLC_ALL\fR, 280 \fBLC_CTYPE\fR, \fBLC_MESSAGES\fR, and \fBNLSPATH\fR. 281 .SH EXIT STATUS 282 .sp 283 .LP 284 The following exit values are returned: 285 .sp 286 .ne 2 287 .na 288 \fB\fB0\fR\fR 289 .ad 290 .RS 6n 291 Successful completion. 292 .RE 293 294 .sp 295 .ne 2 296 .na 297 \fB\fB>0\fR\fR 298 .ad 299 .RS 6n 300 An error occurred. 301 .RE 302 303 .SH ATTRIBUTES 304 .sp 305 .LP 306 See \fBattributes\fR(5) for descriptions of the following attributes: 307 .SS "/usr/bin/head" 308 .sp 309 310 .sp 311 .TS 312 box; 313 c | c 314 l | l . 315 ATTRIBUTE TYPE ATTRIBUTE VALUE 316 _ 317 CSI Enabled 318 _ 319 Interface Stability Committed 320 _ 321 Standard See \fBstandards\fR(5). 322 .TE 323 324 .SS "ksh93" 325 .sp 326 327 .sp 328 .TS 329 box; 330 c | c 331 l | l . 332 ATTRIBUTE TYPE ATTRIBUTE VALUE 333 _ 334 Interface Stability See below. 335 .TE 336 337 .sp 338 .LP 339 The \fBksh93\fR built-in binding to \fB/bin\fR and \fB/usr/bin\fR is Volatile. 340 The built-in interfaces are Uncommitted. 341 .SH SEE ALSO 342 .sp 343 .LP 344 \fBcat\fR(1), \fBksh93\fR(1), \fBmore\fR(1), \fBpg\fR(1), \fBtail\fR(1), 345 \fBattributes\fR(5), \fBenviron\fR(5), \fBlargefile\fR(5), \fBstandards\fR(5)