ApacheのログからGoogleからの検索キーワードを抽出する方法

#!/usr/local/bin/perl
use strict;
use warnings;

sub url_decode($) {
  my $str = shift;
  $str =~ tr/+/ /;
  $str =~ s/%([0-9A-Fa-f][0-9A-Fa-f])/pack('H2', $1)/eg;
  return $str;
}

while(<>){
	if(m,http://www.google.co[a-z\.]+/search\?([^"]+),){
		my $s = url_decode (${1});
		my ($m) = ($s =~ m|q=([^&]+)|);
		print "${m}\n";
	}
}

cat //var/log/httpd-access.log | perl get_keyword.pl

cat //var/log/httpd-access.log | perl get_keyword.pl | sort -u

cat //var/log/httpd-access.log | perl get_keyword.pl | uniq -c 

cat //var/log/httpd-access.log | perl get_keyword.pl | nkf -e