regex grep

grep_regex.pl

#!/usr/bin/perl

$/ = undef;
$file = <DATA>;
$/ = "\n";

$lines_up = 2;
$lines_down = 1;
$pattern = 'bbb';

@matches =  $file =~ /((?:.*\n?){$lines_up})
		  (.*$pattern.*\n?)
		  ((?:.*\n?){$lines_down})/gx;
$run = 0;
@vals = qw(lines_up pattern lines_down);
for (@matches) {
	if (! ($index = $run++ % 3)) {
		print "match #" . (int($run / 3) + 1) . " in file\n";
	}
	print $vals[$index] . ":\n$_\n";
	
}
#print "1:$1\n2:$2\n3:$3";

__DATA__
#begin
aaa
bbb
ccc
ddd
#end

#begin2
xxx
ccc
bbb
#end2

A quick regex which emulates the grep-like functionality of finding a lines and getting previous and following lines.