$string =~ m#
             (some pattern)
            #x;

##</code><code>##

#!/usr/bin/perl -w
use strict;

die <<USAGE unless @ARGV and @ARGV <= 2;
$0 strips comment lines beginning with # from perl code
usage: perl $0 infile [outfile]
    (output to stdout if no outfile given)
USAGE

my $infile  = shift;
my $outfile = shift || '-';

open(IN,"< $infile")   or die "Couldn't open $infile: $!";
open(OUT, ">$outfile") or die "Couldn't open $outfile: $!";

my ($code, $comments) = (0,0);

while(<IN>) {
    $comments++ and next if /^\s*#[^!]/;
    print OUT;
    $code++
}

close IN;
close OUT;

my $total = $code + $comments;
print<<SUMMARY;
    $total lines read from $infile
    $comments comment lines detected in $infile
    $code lines written to $outfile
SUMMARY