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

my ($input1, $input2) = @ARGV;

open( INPUT1, $input1 );
open( INPUT2, $input2 );

while( my $input1_line = <INPUT1> )
{
    if( $input1_line =~ m|<source>| )
    {
    while( my $input2_line = <INPUT2> )
    {
        if( $input2_line =~ m|<source>(.+?)</source>| ) {
        $input1_line =~ s|<source>.*?</source>|<source>$1</source>|;
        last;
        }
    }
    }
    print $input1_line;
}

close( INPUT1 );
close( INPUT2 );