tcpdump filter

gistfile1.pl

#!/usr/bin/env perl

$buf = '';

while(<STDIN>) {
    $flag = $_ =~ m/^\s+0x[\da-f]{4}:  /;
    if (!$flag) {
        $buf =~ s/\s//g;
        $buf =~ s/[0-9A-Fa-f][0-9A-Fa-f]/pack("C", hex $&)/eg;
        $buf = substr($buf, 52);
        $buf =~ s/[\x00-\x08\x0b-\x0c\x0e-\x1f\x7f-\xff]/ /g;
        print "$buf\n\n";
        $buf = '';
        print $_;
    } else {
        $_ =~ s/^[^:]+:  //gm;
        $buf .= $_;
    }
}