Latest revision as of 09:55, 3 September 2024

Find pattern in data stream (files, standard input)

grep <pattern> <files>: Find lines matching pattern in any of the files.; When multiple files are scanned the filename is reported too (see -h below)

Useful options

0 (true) if one or more matches are found

1 (false) if no matches are found

@@ Line 2: / Line 2: @@
 ;grep <pattern>  <files>
-:Find pattern in any of the files.
+:Find lines matching pattern in any of the files.
 :When multiple files are scanned the filename is reported too (see -h below)
-;Useful options
+;zgrep <pattern>  <files>
+:Search possibly gzipped files.
+=Useful options=
 ;-i
 :Ignore case
+;-v
+:Negate the match, show all lines not having the pattern
+;-l
+:Only report filename of files with matches
+;-H -h
+:Force or suppress reporting of filenames.
 ;-n
-:Only report filname of files with matches
-;-h
-:Suppress reporting of filenames when multiple files are scanned.
-;-l
 :Report linenumber of matches too
+;-f <file>
+:Get patterns from <file>. One(1) pattern per line.
+;-C 2
+:Print the context meaning 2 line before and after the matching line.
+=Return value ( $? )=
+(true) if one or more matches are found
+(false) if no matches are found