Thanks almut,

You are right, I forgot that on the first time $_ contains the original value so in the next iterations there is no match at all, I created the local var in the loop so I never change my template:

for ($counter=0; $counter<$total; $counter++) {
    foreach (@template) {
        my $line = $_;
        $line =~ s/$replacement/${prefix}-${counter}/;
        print $line;
    }
}
[download]

JavaFan, I don't think that was what I needed but thanks!