Hi dee00zee, I see you've written a few nodes now, and i wonder why you're not using <code> tags.
Since you're not totally new here, i assume you have read Perl Monks Approved HTML tags and Writeup Formatting Tips?

#!/bin/perl
use strict;

open(IN,"file1");
open(IN2,"file2");
open (OUT,"> output");

while (my $str = <IN>) {
        chomp($str);

        my $data = <IN2>;

        $data =~ s/(.*?)\s(.*)/$1 $str $2/;

        print OUT ($data);
}
[download]