use strict;
use Cwd 'abs_path';
+my $file = '/proc/mounts';
my $dir = shift || '/';
$dir = abs_path($dir);
$dir =~ s#([^/]*)$##;
$trailing = '' if $trailing eq '.' || !-d "$dir$trailing";
$trailing .= '/' if $trailing ne '';
-open(IN, '/proc/mounts') or die $!;
+open(IN, $file) or die "Unable to open $file: $!\n";
while (<IN>) {
$_ = (split)[1];
next unless s#^\Q$dir$trailing\E##o && $_ ne '';