| GREP(1) | GREP(1)
| NAME
| grep, g – search a file for a pattern
SYNOPSIS
| `grep` [ option ... ] pattern [ file ... ]
`g` [ option ... ] pattern [ file ... ]
DESCRIPTION
| Grep searches the input files (standard input default) for lines that match the pattern, a regular expression as defined in regexp(7) with the addition of a newline character as an alternative (substitute for `|`) with lowest precedence. Normally, each line matching the pattern is ‘selected’, and each selected line is copied to the standard output. The options are `−c` Print only a count of matching lines. `−h` Do not print file name tags (headers) with output lines. `−e` The following argument is taken as a pattern. This option makes it easy to specify patterns that might confuse argument parsing, such as `−n`. `−i` Ignore alphabetic case distinctions. The implementation folds into lower case all letters in the pattern and input before interpretation. Matched lines are printed in their original form. `−l` (ell) Print the names of files with selected lines; don’t print the lines. `−L` Print the names of files with no selected lines; the converse of `−l`. `−n` Mark each printed line with its line number counted in its file. `−s` Produce no output, but return status. `−v` Reverse: print lines that do not match the pattern. `−f` The pattern argument is the name of a file containing regular expressions one per line. `−b` Don’t buffer the output: write each output line as soon as it is discovered.
Output lines are tagged by file name when there is more than one input file. (To force this tagging, include `/dev/null` as a file name argument.)
Care should be taken when using the shell metacharacters `$*[^|()=\` and newline in pattern; it is safest to enclose the entire expression in single quotes `'`...`'`. An expression starting with ’*’ will treat the rest of the expression as literal characters.
G invokes grep with `−n` and forces tagging of output lines by file name. If no files are listed, it searches all files matching
| `*.C *.b *.c *.h *.m *.cc *.java *.cgi *.pl *.py *.tex *.ms`
SOURCE
| `/usr/local/plan9/src/cmd/grep /usr/local/plan9/bin/g`
SEE ALSO
| ed(1), awk(1), sed(1), sam(1), regexp(7)
DIAGNOSTICS
| Exit status is null if any lines are selected, or non-null when no lines are selected or an error occurs.