GREP(1) GREP(1) NAME grep, egrep, fgrep - search a file for a pattern SYNOPSIS grep [ options ] expression [ files ] egrep [ options ] [ expression ] [ files ] fgrep [ options ] [ strings ] [ files ] DESCRIPTION Commands of the grep family search the input files (standard input default) for lines matching a pattern. Normally, each line found is copied to the standard output. Grep patterns are limited regular expressions in the style of ed(1); it uses a compact non-deterministic algorithm. Egrep patterns are full regular expressions; it uses a fast deterministic algorithm. Fgrep patterns are fixed strings; it is fast and compact. The following options are recognized: -v All lines but those matching are printed. -x (Exact) only lines matched in their entirety are printed (fgrep only). -c Only a count of matching lines is printed. -i Ignore alphabetic case distinctions. -l Only the names of files with matching lines are listed (once), separated by new-lines. -n Each line is preceded by its relative line number in the file. -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. -h Do not print filename headers with output lines. -s No output is produced, only status. -e expression Same as a simple expression argument, but useful when the expression begins with a -. -f file The regular expression (egrep) or strings list (fgrep) is taken from the file. Output lines are tagged by filename when there is more than one input file. Care should be taken when using the shell metacharacters $*[^|()\ in expression; it is safest to enclose the entire expression in single quotes '...'. Fgrep searches for lines that contain one of the strings separated by new-lines. Egrep accepts regular expressions as in ed(1), except for GREP(1) GREP(1) \(, \), and \n, with the addition of: 1. A regular expression followed by + matches one or more occurrences of the expression. 2. A regular expression followed by ? matches 0 or 1 occurrence. 3. Two regular expressions separated by | or newline match ocurrences of either. 4. Parentheses () specify grouping. The order of precedence of operators is , then *?+, then concatenation, then | and new-line. SEE ALSO ed(1), sed(1), sh(1). DIAGNOSTICS Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files (even if matches were found). BUGS Ideally there should be only one grep, but we do not know a single algorithm that spans a wide enough range of space- time tradeoffs. Lines are truncated at BUFSIZ characters; see setbuf(3). Null characters behave as end-of-line in matches.