NAME grep - search lines in files for matching patternsSYNOPSIS egrep [ options ] [ pattern ] [ file ... ]DESCRIPTION The grep commands search the named input files for lines containing a match for the given patterns. Matching lines are printed by default. The standard input is searched if no files are given or when the file - is specified. There are six variants of grep, each one using a different form of pattern, controlled either by option or the command path base name. Details of each variant may be found in regex(3). grep The default basic regular expressions (no alternations.) egrep Extended regular expressions (alternations, one or more.) pgrep perl(1) regular expressions (lenient extended.) xgrep Augmented regular expressions (conjunction, negation.) fgrep Fixed string expressions. agrep Approximate regular expressions (not implemented.)OPTIONS -G, --basic-regexp grep mode (default): basic regular expression patterns. -E, --extended-regexp egrep mode: extended regular expression patterns. -X, --augmented-regexp xgrep mode: augmented regular expression patterns. -P, --perl-regexp pgrep mode: perl(1) regular expression patterns. -F, --fixed-string fgrep mode: fixed string patterns. -A, --approximate-regexp agrep mode: approximate regular expression patterns (not implemented.) -C, --context[=before[,after]] Set the matched line context before and after count. By default only matched lines are printed. The option value may be omitted. The default value is 2,2. -c, --count Only print a matching line count for each file. -e, --expression|pattern|regexp=pattern Specify a matching pattern. More than one pattern implies alternation. If this option is specified then the command line pattern must be omitted. -f, --file=pattern-file Each line in pattern-file is a pattern, placed into a single alternating expression. -H, --filename|with-filename Prefix each matched line with the containing file name. -h, --no-filename Suppress containing file name prefix for each matched line. -i, --ignore-case Ignore case when matching. -l, --files-with-matches Only print file names with at least one match. -L, --files-without-matches Only print file names with no matches. -b, --highlight Highlight matches using the ansi terminal bold sequence. -v, --invert-match|revert-match Invert the pattern match sense. -m, --label All patterns must be of the form label:pattern. Match and count output will be prefixed by the corresponding label:. -O, --lenient Enable lenient pattern interpretation. This is the default. -x, --line-match|line-regexp Force patterns to match complete lines. -n, --number|line-number Prefix each matched line with its line number. -N, --name=name Set the standard input file name prefix to name. The default value is empty. -q, --quiet|silent Do not print matching lines. -S, --strict Enable strict pattern interpretation with diagnostics. -s, --suppress|no-messages Suppress error and warning messages. -t, --total Only print a single matching line count for all files. -T, --test=test Enable implementation specific tests. -w, --word-match|word-regexp Force patterns to match complete words. -a Ignored for GNU compatibility.DIAGNOSTICS Exit status 0 if matches were found, 1 if no matches were found, where -v invertes the exit status. Exit status 2 for other errors that are accompanied by a message on the standard error.SEE ALSO ed(1), sed(1), perl(1), regex(3)CAVEATS Some expressions of necessity require exponential space and/or time.BUGS Some expressions may use sub-optimal algorithms. For example, don't use this implementation to compute primes.IMPLEMENTATION version grep (AT&T Research) 2006-06-14 author Glenn Fowler <gsf@research.att.com> author David Korn <dgk@research.att.com> copyright Copyright (c) 1992-2009 AT&T Intellectual Property license http://www.opensource.org/licenses/cpl1.0.txt