#!/usr/bin/perl

use strict;
use warnings;

my $mountlist = `mount`;

my %mounts;
$mounts{$2} = $1 while($mountlist =~ /(.*) on (.*) type.*\n/g);

my $location = `pwd`;
chomp $location;

my $mount_dir = $location;

$mount_dir =~ s#/[^/]*$## while $mount_dir && !$mounts{$mount_dir};

$mount_dir ||= '/'; # Add the 'trailing' slash back in if we're mounted as root

print "Directory $location is on device $mounts{$mount_dir}\n";