#! /usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

open my $fh, '>', $_ for my @files = qw( a1 a2 b1 b2 );

for my $mask ('a*', 'b*') {
    while (my $f = glob $mask) {
        say $f;
        last
    }
}

unlink @files;


##</code><code>##

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,