{
  '/a/b/c/dt/data/SUSE/tool/0.9.0' => '/a/b/c/dt/tools/SUSE/tool/0.9.0',
  '/nfs/us/tools/SUSE12' => '/usr/bin',
  '/a/b/c' => '/p'
};

##</code><code>##

realpath /p # Yields /a/b/c

##</code><code>##

{
  '/a/b/c/dt/data/SUSE/tool/0.9.0' => '/p/dt/tools/SUSE/tool/0.9.0',
  '/nfs/us/tools/SUSE12' => '/usr/bin',
  '/a/b/c' => '/p'
};

##</code><code>##

foreach my $actual_path_to_check (keys(%{$virtual_paths_href})) {
    foreach my $current_actual_path (keys(%{$virtual_paths_href})) {
        next if ($actual_path_to_check eq $current_actual_path);
        if ($virtual_paths_href->{$current_actual_path} =~ /^$virtual_paths_href->{$actual_path_to_check}/) {
            # Replace
        }
    }
}