#!/usr/bin/env perl

use strict;
use warnings;

my @data = (
    'a/b/c/d/e/fi le',
    'a/b/c/d/e/fi l e',
    'a/b/c/d/e/f i l e',
    'a/b/c/d/e/f i  l e',
);

for my $datum (@data) {
    print "\n*** Files matching '$datum':\n";
    # $datum =~ y/ /?/; -- see update below
    $datum =~ s/ /[\\;:,-]/g;
    system("ls -1 $datum");
}