#!/usr/bin/perl

use strict;
use warnings;

my @list = qw(a b c d e f g h i j k l m n o p q r s t u v w x y z);

foreach my $f(@list){
        foreach my $s(@list){
                my $fn = $f.$s;
                my $new_fn = '$'.$fn;
                open($new_fn, ">", "Extraction_$fn.txt") or die $!;
        }
}