Grep by paragraph instead of by line.

grepp() { [ $# -eq 1 ] && perl -00ne "print if /$1/i" || perl -00ne "print if /$1/i" < "$2";}
This is a command that I find myself using all the time. It works like regular grep, but returns the paragraph containing the search pattern instead of just the line. It operates on files or standard input. grepp <PATTERN> <FILE> or <SOMECOMMAND> | grepp <PATTERN>
Sample Output
man perl | grepp Pascal
       Perl combines (in the author's opinion, anyway) some of the best features of C, sed, awk, and sh, so people familiar with those languages should have little difficulty with it.
       (Language historians will also note some vestiges of csh, Pascal, and even BASIC-PLUS.)  Expression syntax corresponds closely to C expression syntax.  Unlike most Unix utilities,
       Perl does not arbitrarily limit the size of your data--if you've got the memory, Perl can slurp in your whole file as a single string.  Recursion is of unlimited depth.  And the
       tables used by hashes (sometimes called "associative arrays") grow as necessary to prevent degraded performance.  Perl can use sophisticated pattern matching techniques to scan
       large amounts of data quickly.  Although optimized for scanning text, Perl can also deal with binary data, and can make dbm files look like hashes.  Setuid Perl scripts are safer
       than C programs through a dataflow tracing mechanism that prevents many stupid security holes.


13
2010-01-12 04:30:15

What Others Think

Very nice, but can you think of a smart way to highlight the match, too?
flatcap · 610 weeks ago
Something like this should operate the similar to "grep --color=auto": grepp() { [ $# -eq 1 ] && perl -00ne 'if ( /'$1'/i ){my $s = $_;$s =~ s/'$1'/\033[1;31m$&\033[0m/g; print $s}' || perl -00ne 'if ( /'$1'/i ){my $s = $_;$s =~ s/'$1'/\033[1;31m$&\033[0m/g; print $s}' < "$2";} P.S. @Perl gurus: Suggestions or corrections are very welcome.
eightmillion · 610 weeks ago
I just discovered that it fails if there are spaces in the regex. Quoting the regex fixes it: grepp() { [ $# -eq 1 ] && perl -00ne 'if ( /'"$1"'/i ){$s = $_;$s =~ s/'"$1"'/\033[1;31m$&\033[0m/g; print $s}' || perl -00ne 'if ( /'"$1"'/i ){$s = $_;$s =~ s/'"$1"'/\033[1;31m$&\033[0m/g; print $s}' < "$2";}
eightmillion · 610 weeks ago
Lovely.
flatcap · 609 weeks and 4 days ago
grepp() { x=$1; shift; perl -00ne ' print if /'"$x"'/i ' "$*" ; }
daviddelikat · 481 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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