'\" t
.\" Sccsid @(#)grep.1	1.36 (gritter) 8/14/05
.\" Parts taken from grep(1), Unix 7th edition:
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.TH GREP 1 "8/14/05" "Heirloom Toolchest" "User Commands"
.SH NAME
grep \- search a file for a pattern
.SH SYNOPSIS
.HP
.ad l
.nh
\fB/usr/5bin/grep\fR [\fB\-bchilnrRsvwz\fR]
\fIpattern\fR [\fIfile\fR\ ...]
.HP
.PD 0
.ad l
\fB/usr/5bin/posix/grep\fR [\fB\-E\fR|\fB\-F\fR]
\fB\-e\fI\ pattern_list\fR\ ...
[\fB\-f\fI\ pattern_file\fR] [\fB\-c\fR|\fB\-l\fR|\fB\-q\fR]
[\fB\-bhinrRsvwxz\fR] [\fIfile\fR\ ...]
.HP
.ad l
\fB/usr/5bin/posix/grep\fR [\fB\-E\fR|\fB\-F\fR]
\fB\-f\fI\ pattern_file\fR
[\fB\-e\fI\ pattern_list\fR\ ...] [\fB\-c\fR|\fB\-l\fR|\fB\-q\fR]
[\fB\-bhinrRsvwxz\fR] [\fIfile\fR\ ...]
.HP
.ad l
\fB/usr/5bin/posix/grep\fR [\fB\-E\fR|\fB\-F\fR]
[\fB\-c\fR|\fB\-l\fR|\fB\-q\fR] [\fB\-bhinrRsvwxz\fR]
\fIpattern_list\fR [\fIfile\fR\ ...]
.br
.PD
.ad b
.hy 1
.SH DESCRIPTION
The
.B grep
command searches the lines of the specified files
(or of standard input)
for occurrences of the regular expression
.I pattern.
The default behavior is to print each matching line to standard output.
.PP
The
.B /usr/5bin/grep
command accepts one pattern
that is treated as a simple regular expression;
it uses a compact nondeterministic algorithm.
.PP
The
.B /usr/5bin/posix/grep
command uses basic regular expressions by default
and accepts a newline-separated list of patterns
as described for the
.B \-e
option below.
It uses a deterministic algorithm with moderate space requirements
for most expressions;
backreferences, word delimiters, and multi-character collating elements
cause a nondeterministic algorithm to be used.
.PP
.B /usr/5bin/s42/grep
and
.B /usr/5bin/posix2001/grep
are identical to
.BR /usr/5bin/posix/grep .
.PP
See the description of
.IR ed (1)
for the specifications of simple and basic regular expressions.
.PP
Care should be taken when using the characters
$ * [ ^ | ? \' " ( ) and \e in the expression
as they are also meaningful to the Shell.
It is safest to enclose the entire expression
argument in single quotes \' \'.
.PP
Both
.B /usr/5bin/grep
and
.B /usr/5bin/posix/grep
accept the following options:
.TP
.B \-b
Each line is preceded by the block number on which it was found.
This is sometimes useful
in locating disk block numbers by context.
Block numbers start with 0.
.TP
.B \-c
Only a count of matching lines is printed.
.TP
.B \-h
Normally, the name of each input file is printed before a match
if there is more that one input file.
When this option is present, no file names are printed.
.TP
.B \-i
Upper- and lowercase differences are ignored when searching matches.
.TP
.B \-l
The names of files with matching lines are listed
(once) separated by newlines.
.TP
.B \-n
Each line is preceded by its line number in the file.
Line numbers start with 1.
.TP
.B \-s
Error messages for nonexistent or unreadable files are suppressed.
.TP
.B \-v
All lines but those matching are printed.
.PP
The following options are supported by
.B /usr/5bin/posix/grep
only:
.TP
.BI \-e\  pattern_list
Specifies one or more patterns, separated by newline characters.
A line is selected if one or more of the specified patterns are found.
.TP
.B \-E
All patterns are interpreted as extended regular expressions
as described in
.IR egrep (1).
.TP
.BI \-f\  pattern_file
One or more patterns, separated by newline
characters, are read from
.I pattern_file.
.TP
.B \-F
All patterns are interpreted as fixed strings,
as with
.IR fgrep (1).
.TP
.B \-q
Do not write anything to standard output.
.TP
.B \-x
Consider only lines consisting of the pattern as a whole,
like a regular expression surrounded by
.I ^
and
.I $.
.PP
The following options are supported as extensions:
.TP
.B \-r
With this option given,
.I grep
does not directly search in each given file that is a directory,
but descends it recursively
and scans each regular file found below it.
Device files are ignored.
Symbolic links are followed.
.TP
.B \-R
Operates recursively as with the
.I \-r
option,
but does not follow symbolic links that point to directories
unless if they are explicitly specified as arguments.
.TP
.B \-w
Searches for the patterns treated as words,
as if they were surrounded by `\e<\ \e>'.
Only available if neither the
.I \-E
nor the
.I \-F
option are also supplied.
.TP
.B \-z
If an input file is found to be compressed with
.IR compress (1),
.IR gzip (1),
or
.IR bzip2 (1),
the appropriate compression program is started,
and
.I grep
searches for the pattern in its output.
.SH "ENVIRONMENT VARIABLES"
.TP
.BR LANG ", " LC_ALL
See
.IR locale (7).
.TP
.B LC_COLLATE
Affects the collation order for range expressions,
equivalence classes, and collation symbols
in basic regular expressions.
.TP
.B LC_CTYPE
Determines the mapping of bytes to characters
in both simple and basic regular expressions,
the availability and composition of character classes
in basic regular expressions,
and the case mapping for the
.B \-i
option.
.SH "SEE ALSO"
ed(1),
egrep(1),
fgrep(1),
sed(1),
locale(7)
.SH DIAGNOSTICS
Exit status is 0 if any matches are found,
1 if none, 2 for syntax errors or inaccessible files.
.SH NOTES
If a line contains a
.SM NUL
character,
only matches up to this character are found
(unless
.B /usr/5bin/posix/grep
is used with the
.I \-F
option).
The entire matching line will be printed.
.PP
The LC_COLLATE variable has currently no effect.
Ranges in bracket expressions are ordered
as byte values in single-byte locales
and as wide character values in multibyte locales;
equivalence classes match the given character only,
and multi-character collating elements are not available.
.PP
The options supported by
.B /usr/5bin/posix/grep
that are not accepted by
.B /usr/5bin/grep
can easily be replaced by portable constructs:
Use
.I egrep
instead of
.BR \-E ,
.I fgrep
instead of
.BR \-F .
Use
.I egrep
if you need the
.B \-e
or
.B \-f
option,
use only one of them and that only once;
if necessary, use text processing tools
to generate a single expression list before.
Redirect standard output to
.I /dev/null
for
.B \-q
(the possible speedup with
.I \-q
is never worth human time spent with porting scripts),
and use the
.RI ` ^ '
and
.RI ` $ '
meta-characters instead of
.BR \-x .