Since i wrote it, i might as well post it, even if the answers were more than adequate.

use strict;

my @files = qw(file1.txt file2.txt file3.txt);
my $merge = (@ARGV) ? shift : 'merged.txt';

open (BUFF, '>>', $merge) or die "Unable to open: '$merge'";

while (@files) {
    local $_ = shift @files;
    my $fileData = do { local (*ARGV, $/) = [$merge] and <> };
    print BUFF $fileData;
}

close (BUFF);
[download]