use warnings;
use strict;

my $path = shift;

opendir( my $DIR, $path );

my %dirs;
while ( my $file = readdir($DIR) ) {
    next if ( $file eq '.' || $file eq '..' );
    $dirs{$file} = $file;
}
print "$_\n" for sort keys %dirs; 
#print "$_\n" for sort values %dirs; #same as keys...
#print "$_\n" for sort %dirs;