| grep.texi (53564) | grep.texi (55360) |
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| 1\input texinfo @c -*-texinfo-*- 2@c %**start of header 3@setfilename grep.info 4@settitle grep, print lines matching a pattern 5@c %**end of header 6 7@c This file has the new style title page commands. 8@c Run `makeinfo' rather than `texinfo-format-buffer'. --- 8 unchanged lines hidden (view full) --- 17 18@c Combine indices. 19@syncodeindex ky cp 20@syncodeindex pg cp 21@syncodeindex tp cp 22 23@defcodeindex op 24@syncodeindex op fn | 1\input texinfo @c -*-texinfo-*- 2@c %**start of header 3@setfilename grep.info 4@settitle grep, print lines matching a pattern 5@c %**end of header 6 7@c This file has the new style title page commands. 8@c Run `makeinfo' rather than `texinfo-format-buffer'. --- 8 unchanged lines hidden (view full) --- 17 18@c Combine indices. 19@syncodeindex ky cp 20@syncodeindex pg cp 21@syncodeindex tp cp 22 23@defcodeindex op 24@syncodeindex op fn |
| 25@syncodeindex vr fn |
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| 25 26@ifinfo 27@direntry 28* grep: (grep). print lines matching a pattern. 29@end direntry | 26 27@ifinfo 28@direntry 29* grep: (grep). print lines matching a pattern. 30@end direntry |
| 30This file documents @sc{grep}, a pattern matching engine. | 31This file documents @command{grep}, a pattern matching engine. |
| 31 32 33Published by the Free Software Foundation, 3459 Temple Place - Suite 330 35Boston, MA 02111-1307, USA 36 | 32 33 34Published by the Free Software Foundation, 3559 Temple Place - Suite 330 36Boston, MA 02111-1307, USA 37 |
| 37Copyright (C) 1998 Free Software Foundation, Inc. | 38Copyright 1999 Free Software Foundation, Inc. |
| 38 39Permission is granted to make and distribute verbatim copies of 40this manual provided the copyright notice and this permission notice 41are preserved on all copies. 42 43@ignore 44Permission is granted to process this file through TeX and print the 45results, provided the printed document carries copying permission --- 16 unchanged lines hidden (view full) --- 62 63@titlepage 64@title grep, searching for a pattern 65@subtitle version @value{VERSION}, @value{UPDATED} 66@author Alain Magloire et al. 67 68@page 69@vskip 0pt plus 1filll | 39 40Permission is granted to make and distribute verbatim copies of 41this manual provided the copyright notice and this permission notice 42are preserved on all copies. 43 44@ignore 45Permission is granted to process this file through TeX and print the 46results, provided the printed document carries copying permission --- 16 unchanged lines hidden (view full) --- 63 64@titlepage 65@title grep, searching for a pattern 66@subtitle version @value{VERSION}, @value{UPDATED} 67@author Alain Magloire et al. 68 69@page 70@vskip 0pt plus 1filll |
| 70Copyright @copyright{} 1998 Free Software Foundation, Inc. | 71Copyright @copyright{} 1999 Free Software Foundation, Inc. |
| 71 72@sp 2 73Published by the Free Software Foundation, @* 7459 Temple Place - Suite 330, @* 75Boston, MA 02111-1307, USA 76 77Permission is granted to make and distribute verbatim copies of 78this manual provided the copyright notice and this permission notice --- 8 unchanged lines hidden (view full) --- 87into another language, under the above conditions for modified versions, 88except that this permission notice may be stated in a translation approved 89by the Foundation. 90 91@end titlepage 92@page 93 94 | 72 73@sp 2 74Published by the Free Software Foundation, @* 7559 Temple Place - Suite 330, @* 76Boston, MA 02111-1307, USA 77 78Permission is granted to make and distribute verbatim copies of 79this manual provided the copyright notice and this permission notice --- 8 unchanged lines hidden (view full) --- 88into another language, under the above conditions for modified versions, 89except that this permission notice may be stated in a translation approved 90by the Foundation. 91 92@end titlepage 93@page 94 95 |
| 95@node Top, Introduction, (dir), (dir) 96@comment node-name, next, previous, up | 96@ifnottex 97@node Top 98@top Grep |
| 97 | 99 |
| 98@ifinfo 99This document was produced for version @value{VERSION} of @sc{GNU} @sc{grep}. 100@end ifinfo | 100@command{grep} searches for lines matching a pattern. |
| 101 | 101 |
| 102This document was produced for version @value{VERSION} of @sc{gnu} 103@command{grep}. 104@end ifnottex 105 |
|
| 102@menu 103* Introduction:: Introduction. | 106@menu 107* Introduction:: Introduction. |
| 104* Invoking:: Invoking @sc{grep}; description of options. 105* Diagnostics:: Exit status returned by @sc{grep}. 106* Grep Programs:: @sc{grep} programs. | 108* Invoking:: Invoking @command{grep}; description of options. 109* Diagnostics:: Exit status returned by @command{grep}. 110* Grep Programs:: @command{grep} programs. |
| 107* Regular Expressions:: Regular Expressions. | 111* Regular Expressions:: Regular Expressions. |
| 112* Usage:: Examples. |
|
| 108* Reporting Bugs:: Reporting Bugs. 109* Concept Index:: A menu with all the topics in this manual. | 113* Reporting Bugs:: Reporting Bugs. 114* Concept Index:: A menu with all the topics in this manual. |
| 110* Index:: A menu with all @sc{grep} commands | 115* Index:: A menu with all @command{grep} commands |
| 111 and command-line options. 112@end menu 113 114 | 116 and command-line options. 117@end menu 118 119 |
| 115@node Introduction, Invoking, Top, Top 116@comment node-name, next, previous, up | 120@node Introduction |
| 117@chapter Introduction 118 119@cindex Searching for a pattern. | 121@chapter Introduction 122 123@cindex Searching for a pattern. |
| 120@sc{grep} searches the input files for lines containing a match to a given | 124 125@command{grep} searches the input files 126for lines containing a match to a given |
| 121pattern list. When it finds a match in a line, it copies the line to standard 122output (by default), or does whatever other sort of output you have requested | 127pattern list. When it finds a match in a line, it copies the line to standard 128output (by default), or does whatever other sort of output you have requested |
| 123with options. @sc{grep} expects to do the matching on text. | 129with options. @command{grep} expects to do the matching on text. |
| 124Since newline is also a separator for the list of patterns, there 125is no way to match newline characters in a text. 126 | 130Since newline is also a separator for the list of patterns, there 131is no way to match newline characters in a text. 132 |
| 127@node Invoking, Diagnostics, Introduction, Top 128@comment node-name, next, previous, up 129@chapter Invoking @sc{grep} | 133@node Invoking 134@chapter Invoking @command{grep} |
| 130 | 135 |
| 131@sc{grep} comes with a rich set of options from POSIX.2 and GNU extensions. | 136@command{grep} comes with a rich set of options from @sc{posix.2} and @sc{gnu} 137extensions. |
| 132 133@table @samp 134 135@item -c 136@itemx --count 137@opindex -c 138@opindex -count 139@cindex counting lines 140Suppress normal output; instead print a count of matching | 138 139@table @samp 140 141@item -c 142@itemx --count 143@opindex -c 144@opindex -count 145@cindex counting lines 146Suppress normal output; instead print a count of matching |
| 141lines for each input file. With the @samp{-v}, @samp{--revert-match} option, | 147lines for each input file. With the @samp{-v}, @samp{--invert-match} option, |
| 142count non-matching lines. 143 144@item -e @var{pattern} 145@itemx --regexp=@var{pattern} 146@opindex -e 147@opindex --regexp=@var{pattern} 148@cindex pattern list | 148count non-matching lines. 149 150@item -e @var{pattern} 151@itemx --regexp=@var{pattern} 152@opindex -e 153@opindex --regexp=@var{pattern} 154@cindex pattern list |
| 149Use @var{pattern} as the pattern; useful to protect patterns | 155Use @var{pattern} as the pattern; useful to protect patterns |
| 150beginning with a @samp{-}. 151 | 156beginning with a @samp{-}. 157 |
| 152@item -f @var{file} | 158@item -f @var{file} |
| 153@itemx --file=@var{file} | 159@itemx --file=@var{file} |
| 154@opindex -f 155@opindex --file | 160@opindex -f 161@opindex --file |
| 156@cindex pattern from file | 162@cindex pattern from file |
| 157Obtain patterns from @var{file}, one per line. The empty | 163Obtain patterns from @var{file}, one per line. The empty |
| 158file contains zero patterns, and therefore matches nothing. 159 160@item -i 161@itemx --ignore-case 162@opindex -i 163@opindex --ignore-case 164@cindex case insensitive search | 164file contains zero patterns, and therefore matches nothing. 165 166@item -i 167@itemx --ignore-case 168@opindex -i 169@opindex --ignore-case 170@cindex case insensitive search |
| 165Ignore case distinctions in both the pattern and the input files. | 171Ignore case distinctions in both the pattern and the input files. |
| 166 167@item -l 168@itemx --files-with-matches 169@opindex -l 170@opindex --files-with-matches 171@cindex names of matching files | 172 173@item -l 174@itemx --files-with-matches 175@opindex -l 176@opindex --files-with-matches 177@cindex names of matching files |
| 172Suppress normal output; instead print the name of each input 173file from which output would normally have been printed. | 178Suppress normal output; instead print the name of each input 179file from which output would normally have been printed. |
| 174The scanning of every file will stop on the first match. 175 176@item -n 177@itemx --line-number 178@opindex -n 179@opindex --line-number 180@cindex line numbering | 180The scanning of every file will stop on the first match. 181 182@item -n 183@itemx --line-number 184@opindex -n 185@opindex --line-number 186@cindex line numbering |
| 181Prefix each line of output with the line number within its input file. | 187Prefix each line of output with the line number within its input file. |
| 182 183@item -q 184@itemx --quiet 185@itemx --silent 186@opindex -q 187@opindex --quiet 188@opindex --silent 189@cindex quiet, silent | 188 189@item -q 190@itemx --quiet 191@itemx --silent 192@opindex -q 193@opindex --quiet 194@opindex --silent 195@cindex quiet, silent |
| 190Quiet; suppress normal output. The scanning of every file will stop on | 196Quiet; suppress normal output. The scanning of every file will stop on |
| 191the first match. Also see the @samp{-s} or @samp{--no-messages} option. 192 193@item -s 194@itemx --no-messages 195@opindex -s 196@opindex --no-messages 197@cindex suppress error messages 198Suppress error messages about nonexistent or unreadable files. | 197the first match. Also see the @samp{-s} or @samp{--no-messages} option. 198 199@item -s 200@itemx --no-messages 201@opindex -s 202@opindex --no-messages 203@cindex suppress error messages 204Suppress error messages about nonexistent or unreadable files. |
| 199Portability note: unlike GNU @sc{grep}, BSD @sc{grep} does not comply 200with POSIX.2, because BSD @sc{grep} lacks a @samp{-q} option and its 201@samp{-s} option behaves like GNU @sc{grep}'s @samp{-q} option. Shell 202scripts intended to be portable to BSD @sc{grep} should avoid both | 205Portability note: unlike @sc{gnu} @command{grep}, traditional 206@command{grep} did not conform to @sc{posix.2}, because traditional 207@command{grep} lacked a @samp{-q} option and its @samp{-s} option behaved 208like @sc{gnu} @command{grep}'s @samp{-q} option. Shell scripts intended 209to be portable to traditional @command{grep} should avoid both |
| 203@samp{-q} and @samp{-s} and should redirect 204output to @file{/dev/null} instead. 205 206@item -v | 210@samp{-q} and @samp{-s} and should redirect 211output to @file{/dev/null} instead. 212 213@item -v |
| 207@itemx --revert-match | 214@itemx --invert-match |
| 208@opindex -v | 215@opindex -v |
| 209@opindex --revert-match 210@cindex revert matching | 216@opindex --invert-match 217@cindex invert matching |
| 211@cindex print non-matching lines | 218@cindex print non-matching lines |
| 212Invert the sense of matching, to select non-matching lines. | 219Invert the sense of matching, to select non-matching lines. |
| 213 214@item -x 215@itemx --line-regexp 216@opindex -x 217@opindex --line-regexp 218@cindex match the whole line | 220 221@item -x 222@itemx --line-regexp 223@opindex -x 224@opindex --line-regexp 225@cindex match the whole line |
| 219Select only those matches that exactly match the whole line. | 226Select only those matches that exactly match the whole line. |
| 220 221@end table 222 | 227 228@end table 229 |
| 223@section GNU Extensions | 230@section @sc{gnu} Extensions |
| 224 225@table @samp 226 227@item -A @var{num} 228@itemx --after-context=@var{num} 229@opindex -A 230@opindex --after-context 231@cindex after context 232@cindex context lines, after match 233Print @var{num} lines of trailing context after matching lines. 234 235@item -B @var{num} 236@itemx --before-context=@var{num} 237@opindex -B 238@opindex --before-context 239@cindex before context 240@cindex context lines, before match 241Print @var{num} lines of leading context before matching lines. 242 | 231 232@table @samp 233 234@item -A @var{num} 235@itemx --after-context=@var{num} 236@opindex -A 237@opindex --after-context 238@cindex after context 239@cindex context lines, after match 240Print @var{num} lines of trailing context after matching lines. 241 242@item -B @var{num} 243@itemx --before-context=@var{num} 244@opindex -B 245@opindex --before-context 246@cindex before context 247@cindex context lines, before match 248Print @var{num} lines of leading context before matching lines. 249 |
| 243@item -C 244@itemx --context@var{[=num]} | 250@item -C @var{num} 251@itemx --context=[@var{num}] |
| 245@opindex -C 246@opindex --context 247@cindex context 248Print @var{num} lines (default 2) of output context. 249 250 | 252@opindex -C 253@opindex --context 254@cindex context 255Print @var{num} lines (default 2) of output context. 256 257 |
| 251@item -NUM | 258@item -@var{num} |
| 252@opindex -NUM | 259@opindex -NUM |
| 253Same as @samp{--context=@var{num}} lines of leading and trailing | 260Same as @samp{--context=@var{num}} lines of leading and trailing |
| 254context. However, grep will never print any given line more than once. 255 256 257@item -V 258@itemx --version 259@opindex -V 260@opindex --version 261@cindex Version, printing | 261context. However, grep will never print any given line more than once. 262 263 264@item -V 265@itemx --version 266@opindex -V 267@opindex --version 268@cindex Version, printing |
| 262Print the version number of @sc{grep} to the standard output stream. 263This version number should be included in all bug reports. | 269Print the version number of @command{grep} to the standard output stream. 270This version number should be included in all bug reports. |
| 264 265@item --help 266@opindex --help 267@cindex Usage summary, printing 268Print a usage message briefly summarizing these command-line options 269and the bug-reporting address, then exit. 270 271@item -b 272@itemx --byte-offset 273@opindex -b 274@opindex --byte-offset 275@cindex byte offset 276Print the byte offset within the input file before each line of output. | 271 272@item --help 273@opindex --help 274@cindex Usage summary, printing 275Print a usage message briefly summarizing these command-line options 276and the bug-reporting address, then exit. 277 278@item -b 279@itemx --byte-offset 280@opindex -b 281@opindex --byte-offset 282@cindex byte offset 283Print the byte offset within the input file before each line of output. |
| 277When @sc{grep} runs on MS-DOS or MS-Windows, the printed byte offsets | 284When @command{grep} runs on @sc{ms-dos} or MS-Windows, the printed 285byte offsets |
| 278depend on whether the @samp{-u} (@samp{--unix-byte-offsets}) option is 279used; see below. 280 281@item -d @var{action} 282@itemx --directories=@var{action} | 286depend on whether the @samp{-u} (@samp{--unix-byte-offsets}) option is 287used; see below. 288 289@item -d @var{action} 290@itemx --directories=@var{action} |
| 283@opindex -d | 291@opindex -d |
| 284@opindex --directories 285@cindex directory search | 292@opindex --directories 293@cindex directory search |
| 286If an input file is a directory, use @var{action} to process it. 287By default, @var{action} is @samp{read}, which means that directories are 288read just as if they were ordinary files (some operating systems 289and filesystems disallow this, and will cause @sc{grep} to print error | 294If an input file is a directory, use @var{action} to process it. 295By default, @var{action} is @samp{read}, which means that directories are 296read just as if they were ordinary files (some operating systems 297and filesystems disallow this, and will cause @command{grep} to print error |
| 290messages for every directory). If @var{action} is @samp{skip}, 291directories are silently skipped. If @var{action} is @samp{recurse}, | 298messages for every directory). If @var{action} is @samp{skip}, 299directories are silently skipped. If @var{action} is @samp{recurse}, |
| 292@sc{grep} reads all files under each directory, recursively; this is | 300@command{grep} reads all files under each directory, recursively; this is |
| 293equivalent to the @samp{-r} option. 294 | 301equivalent to the @samp{-r} option. 302 |
| 303@item -H 304@itemx --with-filename 305@opindex -H 306@opindex --With-filename 307@cindex with filename prefix 308Print the filename for each match. 309 |
|
| 295@item -h 296@itemx --no-filename 297@opindex -h 298@opindex --no-filename 299@cindex no filename prefix 300Suppress the prefixing of filenames on output when multiple files are searched. 301 302@item -L 303@itemx --files-without-match 304@opindex -L 305@opindex --files-without-match 306@cindex files which don't match | 310@item -h 311@itemx --no-filename 312@opindex -h 313@opindex --no-filename 314@cindex no filename prefix 315Suppress the prefixing of filenames on output when multiple files are searched. 316 317@item -L 318@itemx --files-without-match 319@opindex -L 320@opindex --files-without-match 321@cindex files which don't match |
| 307Suppress normal output; instead print the name of each input 308file from which no output would normally have been printed. 309The scanning of every file will stop on the first match. | 322Suppress normal output; instead print the name of each input 323file from which no output would normally have been printed. 324The scanning of every file will stop on the first match. |
| 310 311@item -a 312@itemx --text 313@opindex -a 314@opindex --text 315@cindex suppress binary data 316@cindex binary files | 325 326@item -a 327@itemx --text 328@opindex -a 329@opindex --text 330@cindex suppress binary data 331@cindex binary files |
| 317Do not suppress output lines that contain binary data. 318Normally, if the first few bytes of a file indicate | 332Do not suppress output lines that contain binary data. 333Normally, if the first few bytes of a file indicate |
| 319that the file contains binary data, grep outputs only a 320message saying that the file matches the pattern. This | 334that the file contains binary data, grep outputs only a 335message saying that the file matches the pattern. This |
| 321option causes grep to act as if the file is a text | 336option causes grep to act as if the file is a text |
| 322file, even if it would otherwise be treated as binary. | 337file, even if it would otherwise be treated as binary. |
| 323@emph{Warning:} the result might be binary garbage 324printed to the terminal, which can have nasty | 338@emph{Warning:} the result might be binary garbage 339printed to the terminal, which can have nasty |
| 325side-effects if the terminal driver interprets some of 326it as commands. 327 328@item -w 329@itemx --word-regexp 330@opindex -w 331@opindex --word-regexp 332@cindex matching whole words | 340side-effects if the terminal driver interprets some of 341it as commands. 342 343@item -w 344@itemx --word-regexp 345@opindex -w 346@opindex --word-regexp 347@cindex matching whole words |
| 333Select only those lines containing matches that form 334whole words. The test is that the matching substring 335must either be at the beginning of the line, or preceded | 348Select only those lines containing matches that form 349whole words. The test is that the matching substring 350must either be at the beginning of the line, or preceded |
| 336by a non-word constituent character. Similarly, 337it must be either at the end of the line or followed by | 351by a non-word constituent character. Similarly, 352it must be either at the end of the line or followed by |
| 338a non-word constituent character. Word-constituent | 353a non-word constituent character. Word-constituent |
| 339characters are letters, digits, and the underscore. 340 341@item -r 342@itemx --recursive 343@opindex -r 344@opindex --recursive 345@cindex recursive search 346@cindex searching directory trees --- 7 unchanged lines hidden (view full) --- 354Obsolete synonym for @samp{-i}. 355 356@item -U 357@itemx --binary 358@opindex -U 359@opindex --binary 360@cindex DOS/Windows binary files 361@cindex binary files, DOS/Windows | 354characters are letters, digits, and the underscore. 355 356@item -r 357@itemx --recursive 358@opindex -r 359@opindex --recursive 360@cindex recursive search 361@cindex searching directory trees --- 7 unchanged lines hidden (view full) --- 369Obsolete synonym for @samp{-i}. 370 371@item -U 372@itemx --binary 373@opindex -U 374@opindex --binary 375@cindex DOS/Windows binary files 376@cindex binary files, DOS/Windows |
| 362Treat the file(s) as binary. By default, under MS-DOS 363and MS-Windows, @sc{grep} guesses the file type by looking 364at the contents of the first 32KB read from the file. 365If @sc{grep} decides the file is a text file, it strips the 366CR characters from the original file contents (to make 367regular expressions with @code{^} and @code{$} work correctly). | 377Treat the file(s) as binary. By default, under @sc{ms-dos} 378and MS-Windows, @command{grep} guesses the file type by looking 379at the contents of the first 32kB read from the file. 380If @command{grep} decides the file is a text file, it strips the 381@code{CR} characters from the original file contents (to make 382regular expressions with @code{^} and @code{$} work correctly). |
| 368Specifying @samp{-U} overrules this guesswork, causing all | 383Specifying @samp{-U} overrules this guesswork, causing all |
| 369files to be read and passed to the matching mechanism 370verbatim; if the file is a text file with CR/LF pairs 371at the end of each line, this will cause some regular 372expressions to fail. This option is only supported on 373MS-DOS and MS-Windows. | 384files to be read and passed to the matching mechanism 385verbatim; if the file is a text file with @code{CR/LF} pairs 386at the end of each line, this will cause some regular 387expressions to fail. This option has no effect on platforms other than 388@sc{ms-dos} and MS-Windows. |
| 374 375@item -u 376@itemx --unix-byte-offsets 377@opindex -u 378@opindex --unix-byte-offsets 379@cindex DOS byte offsets 380@cindex byte offsets, on DOS/Windows | 389 390@item -u 391@itemx --unix-byte-offsets 392@opindex -u 393@opindex --unix-byte-offsets 394@cindex DOS byte offsets 395@cindex byte offsets, on DOS/Windows |
| 381Report Unix-style byte offsets. This switch causes 382@sc{grep} to report byte offsets as if the file were Unix style 383text file, i.e. the byte offsets ignore the CR characters which were 384stripped off. This will produce results identical to running @sc{grep} on 385a Unix machine. This option has no effect unless @samp{-b} 386option is also used; it is only supported on MS-DOS and | 396Report Unix-style byte offsets. This switch causes 397@command{grep} to report byte offsets as if the file were Unix style 398text file, i.e., the byte offsets ignore the @code{CR} characters which were 399stripped. This will produce results identical to running @command{grep} on 400a Unix machine. This option has no effect unless @samp{-b} 401option is also used; it has no effect on platforms other than @sc{ms-dos} and |
| 387MS-Windows. 388 | 402MS-Windows. 403 |
| 404@item --mmap 405@opindex --mmap 406@cindex memory mapped input 407If possible, use the @code{mmap} system call to read input, instead of 408the default @code{read} system call. In some situations, @samp{--mmap} 409yields better performance. However, @samp{--mmap} can cause undefined 410behavior (including core dumps) if an input file shrinks while 411@command{grep} is operating, or if an I/O error occurs. 412 413@item -Z 414@itemx --null 415@opindex -Z 416@opindex --null 417@cindex zero-terminated file names 418Output a zero byte (the @sc{ascii} @code{NUL} character) instead of the 419character that normally follows a file name. For example, @samp{grep 420-lZ} outputs a zero byte after each file name instead of the usual 421newline. This option makes the output unambiguous, even in the presence 422of file names containing unusual characters like newlines. This option 423can be used with commands like @samp{find -print0}, @samp{perl -0}, 424@samp{sort -z}, and @samp{xargs -0} to process arbitrary file names, 425even those that contain newline characters. 426 427@item -z 428@itemx --null-data 429@opindex -z 430@opindex --null-data 431@cindex zero-terminated lines 432Treat the input as a set of lines, each terminated by a zero byte (the 433@sc{ascii} @code{NUL} character) instead of a newline. Like the @samp{-Z} 434or @samp{--null} option, this option can be used with commands like 435@samp{sort -z} to process arbitrary file names. 436 |
|
| 389@end table 390 | 437@end table 438 |
| 391Several additional options control which variant of the @sc{grep} | 439Several additional options control which variant of the @command{grep} |
| 392matching engine is used. @xref{Grep Programs}. 393 | 440matching engine is used. @xref{Grep Programs}. 441 |
| 394@sc{grep} uses the environment variable @var{LANG} to 395provide internationalization support, if compiled with this feature. | 442@section Environment Variables |
| 396 | 443 |
| 397@node Diagnostics, Grep Programs, Invoking, Top 398@comment node-name, next, previous, up | 444Grep's behavior is affected by the following environment variables. 445@cindex environment variables 446 447@table @code 448 449@item GREP_OPTIONS 450@vindex GREP_OPTIONS 451@cindex default options environment variable 452This variable specifies default options to be placed in front of any 453explicit options. For example, if @code{GREP_OPTIONS} is @samp{--text 454--directories=skip}, @command{grep} behaves as if the two options 455@samp{--text} and @samp{--directories=skip} had been specified before 456any explicit options. Option specifications are separated by 457whitespace. A backslash escapes the next character, so it can be used to 458specify an option containing whitespace or a backslash. 459 460@item LC_ALL 461@itemx LC_MESSAGES 462@itemx LANG 463@vindex LC_ALL 464@vindex LC_MESSAGES 465@vindex LANG 466@cindex language of messages 467@cindex message language 468@cindex national language support 469@cindex NLS 470@cindex translation of message language 471These variables specify the @code{LC_MESSAGES} locale, which determines 472the language that @command{grep} uses for messages. The locale is determined 473by the first of these variables that is set. American English is used 474if none of these environment variables are set, or if the message 475catalog is not installed, or if @command{grep} was not compiled with national 476language support (@sc{nls}). 477 478@item LC_ALL 479@itemx LC_CTYPE 480@itemx LANG 481@vindex LC_ALL 482@vindex LC_CTYPE 483@vindex LANG 484@cindex character type 485@cindex national language support 486@cindex NLS 487These variables specify the @code{LC_CTYPE} locale, which determines the 488type of characters, e.g., which characters are whitespace. The locale is 489determined by the first of these variables that is set. The @sc{posix} 490locale is used if none of these environment variables are set, or if the 491locale catalog is not installed, or if @command{grep} was not compiled with 492national language support (@sc{nls}). 493 494@item POSIXLY_CORRECT 495@vindex POSIXLY_CORRECT 496If set, @command{grep} behaves as @sc{posix.2} requires; otherwise, 497@command{grep} behaves more like other @sc{gnu} programs. @sc{posix.2} 498requires that options that 499follow file names must be treated as file names; by default, such 500options are permuted to the front of the operand list and are treated as 501options. Also, @sc{posix.2} requires that unrecognized options be 502diagnosed as 503``illegal'', but since they are not really against the law the default 504is to diagnose them as ``invalid''. @code{POSIXLY_CORRECT} also 505disables @code{_@var{N}_GNU_nonoption_argv_flags_}, described below. 506 507@item _@var{N}_GNU_nonoption_argv_flags_ 508@vindex _@var{N}_GNU_nonoption_argv_flags_ 509(Here @code{@var{N}} is @command{grep}'s numeric process ID.) If the 510@var{i}th character of this environment variable's value is @samp{1}, do 511not consider the @var{i}th operand of @command{grep} to be an option, even if 512it appears to be one. A shell can put this variable in the environment 513for each command it runs, specifying which operands are the results of 514file name wildcard expansion and therefore should not be treated as 515options. This behavior is available only with the @sc{gnu} C library, and 516only when @code{POSIXLY_CORRECT} is not set. 517 518@end table 519 520@node Diagnostics |
| 399@chapter Diagnostics | 521@chapter Diagnostics |
| 522 |
|
| 400Normally, exit status is 0 if matches were found, and 1 if no matches 401were found (the @samp{-v} option inverts the sense of the exit status). | 523Normally, exit status is 0 if matches were found, and 1 if no matches 524were found (the @samp{-v} option inverts the sense of the exit status). |
| 402Exit status is 2 if there were syntax errors in the pattern, | 525Exit status is 2 if there were syntax errors in the pattern, |
| 403inaccessible input files, or other system errors. 404 | 526inaccessible input files, or other system errors. 527 |
| 405@node Grep Programs, Regular Expressions, Diagnostics, Top 406@comment node-name, next, previous, up 407@chapter @sc{grep} programs | 528@node Grep Programs 529@chapter @command{grep} programs |
| 408 | 530 |
| 409@sc{grep} searches the named input files (or standard input if no | 531@command{grep} searches the named input files (or standard input if no |
| 410files are named, or the file name @file{-} is given) for lines containing | 532files are named, or the file name @file{-} is given) for lines containing |
| 411a match to the given pattern. By default, @sc{grep} prints the matching lines. 412There are three major variants of @sc{grep}, controlled by the following options. | 533a match to the given pattern. By default, @command{grep} prints the 534matching lines. There are three major variants of @command{grep}, 535controlled by the following options. |
| 413 414@table @samp 415 416@item -G 417@itemx --basic-regexp 418@opindex -G 419@opindex --basic-regexp 420@cindex matching basic regular expressions | 536 537@table @samp 538 539@item -G 540@itemx --basic-regexp 541@opindex -G 542@opindex --basic-regexp 543@cindex matching basic regular expressions |
| 421Interpret pattern as a basic regular expression. This is the default. | 544Interpret pattern as a basic regular expression. This is the default. |
| 422 423@item -E | 545 546@item -E |
| 424@item --extended-regexp | 547@itemx --extended-regexp |
| 425@opindex -E 426@opindex --extended-regexp 427@cindex matching extended regular expressions | 548@opindex -E 549@opindex --extended-regexp 550@cindex matching extended regular expressions |
| 428Interpret pattern as an extended regular expression. | 551Interpret pattern as an extended regular expression. |
| 429 430 431@item -F 432@itemx --fixed-strings 433@opindex -F 434@opindex --fixed-strings 435@cindex matching fixed strings 436Interpret pattern as a list of fixed strings, separated 437by newlines, any of which is to be matched. 438 439@end table 440 441In addition, two variant programs @sc{egrep} and @sc{fgrep} are available. | 552 553 554@item -F 555@itemx --fixed-strings 556@opindex -F 557@opindex --fixed-strings 558@cindex matching fixed strings 559Interpret pattern as a list of fixed strings, separated 560by newlines, any of which is to be matched. 561 562@end table 563 564In addition, two variant programs @sc{egrep} and @sc{fgrep} are available. |
| 442@sc{egrep} is similar (but not identical) to @samp{grep -E}, and 443is compatible with the historical Unix @sc{egrep}. @sc{fgrep} is the | 565@sc{egrep} is the same as @samp{grep -E}. @sc{fgrep} is the |
| 444same as @samp{grep -F}. 445 | 566same as @samp{grep -F}. 567 |
| 446@node Regular Expressions, Reporting Bugs, Grep Programs, Top 447@comment node-name, next, previous, up | 568@node Regular Expressions |
| 448@chapter Regular Expressions 449@cindex regular expressions 450 | 569@chapter Regular Expressions 570@cindex regular expressions 571 |
| 451A @dfn{regular expression} is a pattern that describes a set of strings. | 572A @dfn{regular expression} is a pattern that describes a set of strings. |
| 452Regular expressions are constructed analogously to arithmetic expressions, | 573Regular expressions are constructed analogously to arithmetic expressions, |
| 453by using various operators to combine smaller expressions. 454@sc{grep} understands two different versions of regular expression 455syntax: ``basic'' and ``extended''. In GNU @sc{grep}, there is no 456difference in available functionality using either syntax. 457In other implementations, basic regular expressions are less powerful. 458The following description applies to extended regular expressions; | 574by using various operators to combine smaller expressions. 575@command{grep} understands two different versions of regular expression 576syntax: ``basic'' and ``extended''. In @sc{gnu} @command{grep}, there is no 577difference in available functionality using either syntax. 578In other implementations, basic regular expressions are less powerful. 579The following description applies to extended regular expressions; |
| 459differences for basic regular expressions are summarized afterwards. 460 | 580differences for basic regular expressions are summarized afterwards. 581 |
| 461The fundamental building blocks are the regular expressions that match | 582The fundamental building blocks are the regular expressions that match |
| 462a single character. Most characters, including all letters and digits, | 583a single character. Most characters, including all letters and digits, |
| 463are regular expressions that match themselves. Any metacharacter | 584are regular expressions that match themselves. Any metacharacter |
| 464with special meaning may be quoted by preceding it with a backslash. 465A list of characters enclosed by @samp{[} and @samp{]} matches any 466single character in that list; if the first character of the list is the | 585with special meaning may be quoted by preceding it with a backslash. 586A list of characters enclosed by @samp{[} and @samp{]} matches any 587single character in that list; if the first character of the list is the |
| 467caret @samp{^}, then it | 588caret @samp{^}, then it |
| 468matches any character @strong{not} in the list. For example, the regular 469expression @samp{[0123456789]} matches any single digit. | 589matches any character @strong{not} in the list. For example, the regular 590expression @samp{[0123456789]} matches any single digit. |
| 470A range of @sc{ascii} characters may be specified by giving the first 471and last characters, separated by a hyphen. Finally, certain named 472classes of characters are predefined. Their names are self explanatory, 473and they are : | 591A range of @sc{ascii} characters may be specified by giving the first 592and last characters, separated by a hyphen. |
| 474 | 593 |
| 594Finally, certain named classes of characters are predefined, as follows. 595Their interpretation depends on the @code{LC_CTYPE} locale; the 596interpretation below is that of the @sc{posix} locale, which is the default 597if no @code{LC_CTYPE} locale is specified. 598 |
|
| 475@cindex classes of characters 476@cindex character classes 477@table @samp 478 479@item [:alnum:] | 599@cindex classes of characters 600@cindex character classes 601@table @samp 602 603@item [:alnum:] |
| 480@opindex alnum 481@cindex alphanumeric characters 482Any of [:digit:] or [:alpha:] | 604@opindex alnum 605@cindex alphanumeric characters 606Any of @samp{[:digit:]} or @samp{[:alpha:]} |
| 483 484@item [:alpha:] 485@opindex alpha 486@cindex alphabetic characters | 607 608@item [:alpha:] 609@opindex alpha 610@cindex alphabetic characters |
| 487Any local-specific or one of the @sc{ascii} letters:@* | 611Any letter:@* |
| 488@code{a b c d e f g h i j k l m n o p q r s t u v w x y z},@* 489@code{A B C D E F G H I J K L M N O P Q R S T U V W X Y Z}. 490 | 612@code{a b c d e f g h i j k l m n o p q r s t u v w x y z},@* 613@code{A B C D E F G H I J K L M N O P Q R S T U V W X Y Z}. 614 |
| 615@item [:blank:] 616@opindex blank 617@cindex blank characters 618Space or tab. 619 |
|
| 491@item [:cntrl:] 492@opindex cntrl 493@cindex control characters | 620@item [:cntrl:] 621@opindex cntrl 622@cindex control characters |
| 494Any of @code{BEL}, @code{BS}, @code{CR}, @code{FF}, @code{HT}, 495@code{NL}, or @code{VT}. | 623Any character with octal codes 000 through 037, or @code{DEL} (octal 624code 177). |
| 496 497@item [:digit:] 498@opindex digit 499@cindex digit characters 500@cindex numeric characters 501Any one of @code{0 1 2 3 4 5 6 7 8 9}. 502 503@item [:graph:] 504@opindex graph 505@cindex graphic characters | 625 626@item [:digit:] 627@opindex digit 628@cindex digit characters 629@cindex numeric characters 630Any one of @code{0 1 2 3 4 5 6 7 8 9}. 631 632@item [:graph:] 633@opindex graph 634@cindex graphic characters |
| 506Anything that is not a @samp{[:alphanum:]} or @samp{[:punct:]}. | 635Anything that is not a @samp{[:alnum:]} or @samp{[:punct:]}. |
| 507 508@item [:lower:] 509@opindex lower 510@cindex lower-case alphabetic characters 511Any one of @code{a b c d e f g h i j k l m n o p q r s t u v w x y z}. 512 513@item [:print:] 514@opindex print 515@cindex printable characters 516Any character from the @samp{[:space:]} class, and any character that is | 636 637@item [:lower:] 638@opindex lower 639@cindex lower-case alphabetic characters 640Any one of @code{a b c d e f g h i j k l m n o p q r s t u v w x y z}. 641 642@item [:print:] 643@opindex print 644@cindex printable characters 645Any character from the @samp{[:space:]} class, and any character that is |
| 517@strong{not} in the @samp{[:isgraph:]} class. | 646@strong{not} in the @samp{[:graph:]} class. |
| 518 519@item [:punct:] 520@opindex punct 521@cindex punctuation characters | 647 648@item [:punct:] 649@opindex punct 650@cindex punctuation characters |
| 522Any one of @code{!@: " #% & ' ( ) ; < = > ?@: [ \ ] * + , - .@: / : ^ _ @{ | @}}. | 651Any one of @code{!@: " # $ % & ' ( ) * + , - .@: / : ; < = > ?@: @@ [ \ ] ^ _ ` @{ | @} ~}. |
| 523 | 652 |
| 524 | |
| 525@item [:space:] 526@opindex space 527@cindex space characters 528@cindex whitespace characters 529Any one of @code{CR FF HT NL VT SPACE}. 530 531@item [:upper:] 532@opindex upper 533@cindex upper-case alphabetic characters 534Any one of @code{A B C D E F G H I J K L M N O P Q R S T U V W X Y Z}. 535 536@item [:xdigit:] 537@opindex xdigit 538@cindex xdigit class 539@cindex hexadecimal digits 540Any one of @code{a b c d e f A B C D E F 0 1 2 3 4 5 6 7 8 9}. 541 542@end table 543For example, @samp{[[:alnum:]]} means @samp{[0-9A-Za-z]}, except the latter | 653@item [:space:] 654@opindex space 655@cindex space characters 656@cindex whitespace characters 657Any one of @code{CR FF HT NL VT SPACE}. 658 659@item [:upper:] 660@opindex upper 661@cindex upper-case alphabetic characters 662Any one of @code{A B C D E F G H I J K L M N O P Q R S T U V W X Y Z}. 663 664@item [:xdigit:] 665@opindex xdigit 666@cindex xdigit class 667@cindex hexadecimal digits 668Any one of @code{a b c d e f A B C D E F 0 1 2 3 4 5 6 7 8 9}. 669 670@end table 671For example, @samp{[[:alnum:]]} means @samp{[0-9A-Za-z]}, except the latter |
| 544form is dependent upon the @sc{ascii} character encoding, whereas the 545former is portable. (Note that the brackets in these class names are 546part of the symbolic names, and must be included in addition to 547the brackets delimiting the bracket list). Most metacharacters lose | 672form is dependent upon the @sc{ascii} character encoding, whereas the 673former is portable. (Note that the brackets in these class names are 674part of the symbolic names, and must be included in addition to 675the brackets delimiting the bracket list.) Most metacharacters lose |
| 548their special meaning inside lists. To include a literal @samp{]}, place it 549first in the list. Similarly, to include a literal @samp{^}, place it anywhere | 676their special meaning inside lists. To include a literal @samp{]}, place it 677first in the list. Similarly, to include a literal @samp{^}, place it anywhere |
| 550but first. Finally, to include a literal @samp{-}, place it last. | 678but first. Finally, to include a literal @samp{-}, place it last. |
| 551 552The period @samp{.} matches any single character. The symbol @samp{\w} 553is a synonym for @samp{[[:alnum:]]} and @samp{\W} is a synonym for 554@samp{[^[:alnum]]}. 555 556The caret @samp{^} and the dollar sign @samp{$} are metacharacters that 557respectively match the empty string at the beginning and end | 679 680The period @samp{.} matches any single character. The symbol @samp{\w} 681is a synonym for @samp{[[:alnum:]]} and @samp{\W} is a synonym for 682@samp{[^[:alnum]]}. 683 684The caret @samp{^} and the dollar sign @samp{$} are metacharacters that 685respectively match the empty string at the beginning and end |
| 558of a line. The symbols @samp{\<} and @samp{\>} respectively match the | 686of a line. The symbols @samp{\<} and @samp{\>} respectively match the |
| 559empty string at the beginning and end of a word. The symbol | 687empty string at the beginning and end of a word. The symbol |
| 560@samp{\b} matches the empty string at the edge of a word, and @samp{\B} 561matches the empty string provided it's not at the edge of a word. | 688@samp{\b} matches the empty string at the edge of a word, and @samp{\B} 689matches the empty string provided it's not at the edge of a word. |
| 562 | 690 |
| 563A regular expression may be followed by one of several | 691A regular expression may be followed by one of several |
| 564repetition operators: 565 566 567@table @samp 568 569@item ? 570@opindex ? 571@cindex question mark 572@cindex match sub-expression at most once 573The preceding item is optional and will be matched at most once. 574 575@item * 576@opindex * 577@cindex asterisk 578@cindex match sub-expression zero or more times 579The preceding item will be matched zero or more times. 580 581@item + 582@opindex + | 692repetition operators: 693 694 695@table @samp 696 697@item ? 698@opindex ? 699@cindex question mark 700@cindex match sub-expression at most once 701The preceding item is optional and will be matched at most once. 702 703@item * 704@opindex * 705@cindex asterisk 706@cindex match sub-expression zero or more times 707The preceding item will be matched zero or more times. 708 709@item + 710@opindex + |
| 583@cindex plus sign | 711@cindex plus sign |
| 584The preceding item will be matched one or more times. 585 586@item @{@var{n}@} 587@opindex @{n@} 588@cindex braces, one argument 589@cindex match sub-expression n times 590The preceding item is matched exactly @var{n} times. 591 592@item @{@var{n},@} 593@opindex @{n,@} 594@cindex braces, second argument omitted 595@cindex match sub-expression n or more times 596The preceding item is matched n or more times. 597 | 712The preceding item will be matched one or more times. 713 714@item @{@var{n}@} 715@opindex @{n@} 716@cindex braces, one argument 717@cindex match sub-expression n times 718The preceding item is matched exactly @var{n} times. 719 720@item @{@var{n},@} 721@opindex @{n,@} 722@cindex braces, second argument omitted 723@cindex match sub-expression n or more times 724The preceding item is matched n or more times. 725 |
| 598@item @{,@var{m}@} 599@opindex @{,m@} 600@cindex braces, first argument omitted 601@cindex match sub-expression at most m times 602The preceding item is optional and is matched at most @var{m} times. 603 | |
| 604@item @{@var{n},@var{m}@} 605@opindex @{n,m@} 606@cindex braces, two arguments 607The preceding item is matched at least @var{n} times, but not more than 608@var{m} times. 609 610@end table 611 | 726@item @{@var{n},@var{m}@} 727@opindex @{n,m@} 728@cindex braces, two arguments 729The preceding item is matched at least @var{n} times, but not more than 730@var{m} times. 731 732@end table 733 |
| 612Two regular expressions may be concatenated; the resulting regular | 734Two regular expressions may be concatenated; the resulting regular |
| 613expression matches any string formed by concatenating two substrings | 735expression matches any string formed by concatenating two substrings |
| 614that respectively match the concatenated subexpressions. | 736that respectively match the concatenated subexpressions. |
| 615 | 737 |
| 616Two regular expressions may be joined by the infix operator @samp{|}; the 617resulting regular expression matches any string matching either | 738Two regular expressions may be joined by the infix operator @samp{|}; the 739resulting regular expression matches any string matching either |
| 618subexpression. 619 | 740subexpression. 741 |
| 620Repetition takes precedence over concatenation, which in turn | 742Repetition takes precedence over concatenation, which in turn |
| 621takes precedence over alternation. A whole subexpression may be | 743takes precedence over alternation. A whole subexpression may be |
| 622enclosed in parentheses to override these precedence rules. | 744enclosed in parentheses to override these precedence rules. |
| 623 624The backreference @samp{\@var{n}}, where @var{n} is a single digit, matches the 625substring previously matched by the @var{n}th parenthesized subexpression 626of the regular expression. 627 628@cindex basic regular expressions 629In basic regular expressions the metacharacters @samp{?}, @samp{+}, 630@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning; 631instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{}, 632@samp{\|}, @samp{\(}, and @samp{\)}. 633 | 745 746The backreference @samp{\@var{n}}, where @var{n} is a single digit, matches the 747substring previously matched by the @var{n}th parenthesized subexpression 748of the regular expression. 749 750@cindex basic regular expressions 751In basic regular expressions the metacharacters @samp{?}, @samp{+}, 752@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning; 753instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{}, 754@samp{\|}, @samp{\(}, and @samp{\)}. 755 |
| 634In @sc{egrep} the metacharacter @samp{@{} loses its special meaning; 635instead use @samp{\@{}. This not true for @samp{grep -E}. | 756@cindex interval specifications 757Traditional @command{egrep} did not support the @samp{@{} metacharacter, 758and some @command{egrep} implementations support @samp{\@{} instead, so 759portable scripts should avoid @samp{@{} in @samp{egrep} patterns and 760should use @samp{[@{]} to match a literal @samp{@{}. |
| 636 | 761 |
| 762@sc{gnu} @command{egrep} attempts to support traditional usage by 763assuming that @samp{@{} is not special if it would be the start of an 764invalid interval specification. For example, the shell command 765@samp{egrep '@{1'} searches for the two-character string @samp{@{1} 766instead of reporting a syntax error in the regular expression. 767@sc{posix.2} allows this behavior as an extension, but portable scripts 768should avoid it. |
|
| 637 | 769 |
| 638@node Reporting Bugs, Concept Index, Regular Expressions, Top 639@comment node-name, next, previous, up | 770@node Usage 771@chapter Usage 772 773@cindex Usage, examples 774Here is an example shell command that invokes @sc{gnu} @command{grep}: 775 776@example 777grep -i 'hello.*world' menu.h main.c 778@end example 779 780@noindent 781This lists all lines in the files @file{menu.h} and @file{main.c} that 782contain the string @samp{hello} followed by the string @samp{world}; 783this is because @samp{.*} matches zero or more characters within a line. 784@xref{Regular Expressions}. The @samp{-i} option causes @command{grep} 785to ignore case, causing it to match the line @samp{Hello, world!}, which 786it would not otherwise match. @xref{Invoking}, for more details about 787how to invoke @command{grep}. 788 789@cindex Using @command{grep}, Q&A 790@cindex FAQ about @command{grep} usage 791Here are some common questions and answers about @command{grep} usage. 792 793@enumerate 794 795@item 796How can I list just the names of matching files? 797 798@example 799grep -l 'main' *.c 800@end example 801 802@noindent 803lists the names of all C files in the current directory whose contents 804mention @samp{main}. 805 806@item 807How do I search directories recursively? 808 809@example 810grep -r 'hello' /home/gigi 811@end example 812 813@noindent 814searches for @samp{hello} in all files under the directory 815@file{/home/gigi}. For more control of which files are searched, use 816@command{find}, @command{grep} and @command{xargs}. For example, 817the following command searches only C files: 818 819@smallexample 820find /home/gigi -name '*.c' -print | xargs grep 'hello' /dev/null 821@end smallexample 822 823@item 824What if a pattern has a leading @samp{-}? 825 826@example 827grep -e '--cut here--' * 828@end example 829 830@noindent 831searches for all lines matching @samp{--cut here--}. Without @samp{-e}, 832@command{grep} would attempt to parse @samp{--cut here--} as a list of 833options. 834 835@item 836Suppose I want to search for a whole word, not a part of a word? 837 838@example 839grep -w 'hello' * 840@end example 841 842@noindent 843searches only for instances of @samp{hello} that are entire words; it 844does not match @samp{Othello}. For more control, use @samp{\<} and 845@samp{\>} to match the start and end of words. For example: 846 847@example 848grep 'hello\>' * 849@end example 850 851@noindent 852searches only for words ending in @samp{hello}, so it matches the word 853@samp{Othello}. 854 855@item 856How do I output context around the matching lines? 857 858@example 859grep -C 2 'hello' * 860@end example 861 862@noindent 863prints two lines of context around each matching line. 864 865@item 866How do I force grep to print the name of the file? 867 868Append @file{/dev/null}: 869 870@example 871grep 'eli' /etc/passwd /dev/null 872@end example 873 874@item 875Why do people use strange regular expressions on @command{ps} output? 876 877@example 878ps -ef | grep '[c]ron' 879@end example 880 881If the pattern had been written without the square brackets, it would 882have matched not only the @command{ps} output line for @command{cron}, 883but also the @command{ps} output line for @command{grep}. 884 885@item 886Why does @command{grep} report ``Binary file matches''? 887 888If @command{grep} listed all matching ``lines'' from a binary file, it 889would probably generate output that is not useful, and it might even 890muck up your display. So @sc{gnu} @command{grep} suppresses output from 891files that appear to be binary files. To force @sc{gnu} @command{grep} 892to output lines even from files that appear to be binary, use the 893@samp{-a} or @samp{--text} option. 894 895@item 896Why doesn't @samp{grep -lv} print nonmatching file names? 897 898@samp{grep -lv} lists the names of all files containing one or more 899lines that do not match. To list the names of all files that contain no 900matching lines, use the @samp{-L} or @samp{--files-without-match} 901option. 902 903@item 904I can do @sc{or} with @samp{|}, but what about @sc{and}? 905 906@example 907grep 'paul' /etc/motd | grep 'franc,ois' 908@end example 909 910@noindent 911finds all lines that contain both @samp{paul} and @samp{franc,ois}. 912 913@item 914How can I search in both standard input and in files? 915 916Use the special file name @samp{-}: 917 918@example 919cat /etc/passwd | grep 'alain' - /etc/motd 920@end example 921@end enumerate 922 923@node Reporting Bugs |
| 640@chapter Reporting bugs 641 642@cindex Bugs, reporting 643Email bug reports to @email{bug-gnu-utils@@gnu.org}. 644Be sure to include the word ``grep'' somewhere in the ``Subject:'' field. 645 | 924@chapter Reporting bugs 925 926@cindex Bugs, reporting 927Email bug reports to @email{bug-gnu-utils@@gnu.org}. 928Be sure to include the word ``grep'' somewhere in the ``Subject:'' field. 929 |
| 646Large repetition counts in the @samp{@{m,n@}} construct may cause 647@sc{grep} to use lots of memory. In addition, certain other 648obscure regular expressions require exponential time and | 930Large repetition counts in the @samp{@{m,n@}} construct may cause 931@command{grep} to use lots of memory. In addition, certain other 932obscure regular expressions require exponential time and |
| 649space, and may cause grep to run out of memory. | 933space, and may cause grep to run out of memory. |
| 650Backreferences are very slow, and may require exponential time. | 934Backreferences are very slow, and may require exponential time. |
| 651 652@page | 935 936@page |
| 653@node Concept Index , Index, Reporting Bugs, Top 654@comment node-name, next, previous, up | 937@node Concept Index |
| 655@unnumbered Concept Index 656 657This is a general index of all issues discussed in this manual, with the | 938@unnumbered Concept Index 939 940This is a general index of all issues discussed in this manual, with the |
| 658exception of the @sc{grep} commands and command-line options. | 941exception of the @command{grep} commands and command-line options. |
| 659 660@printindex cp 661 662@page | 942 943@printindex cp 944 945@page |
| 663@node Index, , Concept Index, Top | 946@node Index |
| 664@unnumbered Index 665 | 947@unnumbered Index 948 |
| 666This is an alphabetical list of all @sc{grep} commands and command-line 667options. | 949This is an alphabetical list of all @command{grep} commands, command-line 950options, and environment variables. |
| 668 669@printindex fn 670 671@contents 672@bye | 951 952@printindex fn 953 954@contents 955@bye |