#!/usr/local/bin/perl
use warnings;
use strict;
use URI;
my $base = shift;
die "usage: $0 BASE_URI [FILE...]\n" if @ARGV != 1;
while (<>) {
    s/(href|src)=([""''])(.+?)\2/qq'$1="' . URI->new_abs($3, $base) . '"'/ieg;
    print;
}