.\" $OpenBSD: grep.1,v 1.52 2023/01/04 07:33:00 jmc Exp $ .\" Copyright (c) 1980, 1990, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)grep.1 8.3 (Berkeley) 4/18/94 .\" .Dd $Mdocdate: January 4 2023 $ .Dt GREP 1 .Os .Sh NAME .Nm grep , egrep , fgrep , .Nm zgrep , zegrep , zfgrep .Nd file pattern searcher .Sh SYNOPSIS .Nm grep .Bk -words .Op Fl abcEFGHhIiLlnoqRsUVvwxZ .Op Fl A Ar num .Op Fl B Ar num .Op Fl C Ns Op Ar num .Op Fl e Ar pattern .Op Fl f Ar file .Op Fl m Ar num .Op Fl -binary-files Ns = Ns Ar value .Op Fl -context Ns Op = Ns Ar num .Op Fl -label Ns = Ns Ar name .Op Fl -line-buffered .Op Fl -null .Op Ar pattern .Op Ar .Ek .Sh DESCRIPTION The .Nm grep utility searches any given input files, selecting lines that match one or more patterns. By default, a pattern matches an input line if the regular expression (RE) in the pattern matches the input line without its trailing newline. An empty expression matches every line. Each input line that matches at least one of the patterns is written to the standard output. If no file arguments are specified, the standard input is used. .Pp .Nm grep is used for simple patterns and basic regular expressions .Pq BREs ; .Nm egrep can handle extended regular expressions .Pq EREs . See .Xr re_format 7 for more information on regular expressions. .Nm fgrep is quicker than both .Nm grep and .Nm egrep , but can only handle fixed patterns (i.e. it does not interpret regular expressions). Patterns may consist of one or more lines, allowing any of the pattern lines to match a portion of the input. .Pp .Nm zgrep , .Nm zegrep , and .Nm zfgrep act like .Nm grep , .Nm egrep , and .Nm fgrep , respectively, but accept input files compressed with the .Xr compress 1 or .Xr gzip 1 compression utilities. .Pp The following options are available: .Bl -tag -width indent .It Fl A Ar num Print .Ar num lines of trailing context after each match. See also the .Fl B and .Fl C options. .It Fl a Treat all files as ASCII text. Normally .Nm will simply print .Dq Binary file ... matches if files contain binary characters. Use of this option forces .Nm to output lines matching the specified pattern. .It Fl B Ar num Print .Ar num lines of leading context before each match. See also the .Fl A and .Fl C options. .It Fl b Each output line is preceded by its position (in bytes) in the file. If option .Fl o is also specified, the position of the matched pattern is displayed. .It Fl C Ns Oo Ar num Oc , Fl -context Ns Op = Ns Ar num Print .Ar num lines of leading and trailing context surrounding each match. The default is 2 and is equivalent to .Fl A .Ar 2 .Fl B .Ar 2 . Note: no whitespace may be given between the option and its argument. .It Fl c Only a count of selected lines is written to standard output. .It Fl E Interpret .Ar pattern as an extended regular expression (i.e. force .Nm grep to behave as .Nm egrep ) . .It Fl e Ar pattern Specify a pattern used during the search of the input: an input line is selected if it matches any of the specified patterns. This option is most useful when multiple .Fl e options are used to specify multiple patterns, or when a pattern begins with a dash .Pq Sq - . .It Fl F Interpret .Ar pattern as a set of fixed strings (i.e. force .Nm grep to behave as .Nm fgrep ) . .It Fl f Ar file Read one or more newline separated patterns from .Ar file . Empty pattern lines match every input line. Newlines are not considered part of a pattern. If .Ar file is empty, nothing is matched. .It Fl G Interpret .Ar pattern as a basic regular expression (i.e. force .Nm grep to behave as traditional .Nm grep ) . .It Fl H Always print filename headers .Pq i.e. filenames with output lines. .It Fl h Never print filename headers .Pq i.e. filenames with output lines. .It Fl I Ignore binary files. .It Fl i Perform case insensitive matching. By default, .Nm grep is case sensitive. .It Fl L Only the names of files not containing selected lines are written to standard output. Pathnames are listed once per file searched. If the standard input is searched, the string .Dq (standard input) is written. .It Fl l Only the names of files containing selected lines are written to standard output. .Nm grep will only search a file until a match has been found, making searches potentially less expensive. Pathnames are listed once per file searched. If the standard input is searched, the string .Dq (standard input) is written. .It Fl m Ar num Stop after .Ar num matches. .It Fl n Each output line is preceded by its relative line number in the file, starting at line 1. The line number counter is reset for each file processed. This option is ignored if .Fl c , .Fl L , .Fl l , or .Fl q is specified. .It Fl o Print each match, but only the match, not the entire line. .It Fl q Quiet mode: suppress normal output. .Nm grep will only search a file until a match has been found, making searches potentially less expensive. .It Fl R Recursively search subdirectories listed. If no .Ar file is given, .Nm searches the current working directory. .It Fl s Silent mode. Nonexistent and unreadable files are ignored (i.e. their error messages are suppressed). .It Fl U Search binary files, but do not attempt to print them. .It Fl V Display version information. All other options are ignored. .It Fl v Selected lines are those .Em not matching any of the specified patterns. .It Fl w The expression is searched for as a word (as if surrounded by .Sq [[:<:]] and .Sq [[:>:]] ; see .Xr re_format 7 ) . .It Fl x Only input lines selected against an entire fixed string or regular expression are considered to be matching lines. .It Fl Z Force .Nm grep to behave as .Nm zgrep . .It Fl -binary-files Ns = Ns Ar value Controls searching and printing of binary files. Options are .Ar binary , the default: search binary files but do not print them; .Ar without-match : do not search binary files; and .Ar text : treat all files as text. .It Fl -label Ns = Ns Ar name Print .Ar name instead of the filename before lines. .It Fl -line-buffered Force output to be line buffered. By default, output is line buffered when standard output is a terminal and block buffered otherwise. .It Fl -null Output a zero byte instead of the character that normally follows a file name. This option makes the output unambiguous, even in the presence of file names containing unusual characters like newlines. This is similar to the .Fl print0 primary in .Xr find 1 . .El .Sh EXIT STATUS The .Nm grep utility exits with one of the following values: .Pp .Bl -tag -width Ds -offset indent -compact .It Li 0 One or more lines were selected. .It Li 1 No lines were selected. .It Li >1 An error occurred. .El .Sh EXAMPLES To find all occurrences of the word .Sq patricia in a file: .Pp .Dl $ grep 'patricia' myfile .Pp To find all occurrences of the pattern .Ql .Pp at the beginning of a line: .Pp .Dl $ grep '^\e.Pp' myfile .Pp The apostrophes ensure the entire expression is evaluated by .Nm grep instead of by the user's shell. The caret .Ql ^ matches the null string at the beginning of a line, and the .Ql \e escapes the .Ql \&. , which would otherwise match any character. .Pp To find all lines in a file which do not contain the words .Sq foo or .Sq bar : .Pp .Dl $ grep -v -e 'foo' -e 'bar' myfile .Pp A simple example of an extended regular expression: .Pp .Dl $ egrep '19|20|25' calendar .Pp Peruses the file .Sq calendar looking for either 19, 20, or 25. .Sh SEE ALSO .Xr ed 1 , .Xr ex 1 , .Xr gzip 1 , .Xr sed 1 , .Xr re_format 7 .Sh STANDARDS The .Nm utility is compliant with the .St -p1003.1-2008 specification. .Pp The flags .Op Fl AaBbCGHhILmoRUVwZ are extensions to that specification, and the behaviour of the .Fl f flag when used with an empty pattern file is left undefined. .Pp All long options are provided for compatibility with GNU versions of this utility. .Pp Historic versions of the .Nm grep utility also supported the flags .Op Fl ruy . This implementation supports those options; however, their use is strongly discouraged. .Sh HISTORY The .Nm grep command first appeared in .At v4 .