Section: User Commands (1)Index
grep, g - search a file for a pattern
g[option ...]pattern[file ...]
searches the inputfiles
(standard input default)for lines that match thepattern
,a regular expression as defined inregexp
(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
- Print only a count of matching lines.
- Do not print file name tags (headers) with output lines.
- The following argument is taken as apattern.This option makes it easy to specify patterns thatmight confuse argument parsing, such as-n.
- Ignore alphabetic case distinctions. The implementationfolds into lower case all letters in the pattern and input beforeinterpretation. Matched lines are printed in their original form.
- (ell) Print the names of files with selected lines; don't print the lines.
- Print the names of files with no selected lines;the converse of-l.
- Mark each printed line with its line number counted in its file.
- Produce no output, but return status.
- Reverse: print lines that do not match the pattern.
- The pattern argument is the name of a file containing regularexpressions one per line.
- 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 oneinput file.(To force this tagging, include/dev/nullas a file name argument.)
Care should be taken whenusing the shell metacharacters$*[^|()=\and newlineinpattern;it is safest to enclose theentire expressionin single quotes'...'.An expression starting with '*'will treat the rest of the expressionas literal characters.
Ginvokes grep with-nand 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
Exit status is null if any lines are selected,or non-null when no lines are selected or an error occurs.
- SEE ALSO
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