join $req_file, $dir, $ext

##</code><code>##

#! /usr/bin/perl
use warnings;
use strict;

use File::Basename;

for my $row('./filename.ext', '../filename', 'filename.s1.s2') {
    my ($filename, $dirs, $suffix) = fileparse($row, qr/\..*/);
    substr $suffix, 0, 1, q();  #  Remove the dot.
    print "$_\t" for $filename, $dirs, $suffix;
    print "\n";
}