#!/usr/bin/perl

use strict;
use warnings;

my ($file, $prefix);

walk("C:\\");

sub walk {
		$file = shift;
		$prefix = shift;
        #($file, $prefix) = @_;   # You can also use shift. my $file = shift; my $prefix = shift;
        $prefix ||= "";             # Set $prefix to "" if undefined (first case)
		#print "$file\n";
		if ("$file"=~m/.nsf$/){
			print "Prefix: $prefix\nFile:$file\n";     # print current file.
		}
        if(-d $file) {              # is this a directory?
			chdir $file;
            opendir(DIR, ".");
            my @files = grep {$_ !~ /^\.\.?$/} readdir(DIR);  # Ignore . and ..
            closedir DIR;
            walk($_, "$prefix$file\\") foreach @files;         # recursive call
            chdir "..";
        }
}