Grep: Difference between revisions
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only available in gnu grep via <code>-P</code>, this supports lookahead/lookbehind. | only available in gnu grep via <code>-P</code>, this supports lookahead/lookbehind. | ||
match lines | |||
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
xrandr | grep -P '(?<!dis)connected' # negative lookbehind | xrandr | grep -P '(?<!dis)connected' # negative lookbehind | ||
xrandr | grep -P '(?<=dis)connected' # positive lookehind | xrandr | grep -P '(?<=dis)connected' # positive lookehind | ||
</syntaxhighlight> | |||
extract regex groups | |||
<syntaxhighlight lang="bash"> | |||
xrandr | grep -P '\d+x\d+' -o # extract resolutions(ex: 1920x1080) from every line in xrandr | |||
</syntaxhighlight> | </syntaxhighlight> | ||
</blockquote><!-- Perl --> | </blockquote><!-- Perl --> | ||
</blockquote><!-- Regex --> | </blockquote><!-- Regex --> | ||
Latest revision as of 02:08, 19 July 2021
Search file contents.
Documentation
man grep https://manpages.debian.org/buster/grep/grep.1.en.html
Usage
grep <dir> \ -C3 `# show 3x lines before/after each match` \ -l `# show only matched files` \ -i `# case insensitive search` \ -v `# lines-not matching` \ -E `# extended regex` \ -P `# (gnu-only) perl extended regex (supports lookahead/behind)` \multiline grep
grep -Pzo 'def[^\n]+\n\tfoo'
Regex
Perl
only available in gnu grep via
-P, this supports lookahead/lookbehind.match lines
xrandr | grep -P '(?<!dis)connected' # negative lookbehind xrandr | grep -P '(?<=dis)connected' # positive lookehindextract regex groups
xrandr | grep -P '\d+x\d+' -o # extract resolutions(ex: 1920x1080) from every line in xrandr
