If your goal is to write a text adventure, you should not be rolling your own tools. It's a big task, and it's been done before. Go to The Interactive Fiction Archive and download a development system (TADS is a good one).

If your goal is to enhance your Perl programming skills, I recommend you set modest goals, particularly for your command parser. What are you finding difficult about recognizing when a command is entered? It seems like you should have a main loop that looks like this:

while (<STDIN>) {
  # Command is in $_
  chomp;
  handle_command($_);
}
[download]

Where your handle_command sub is going to split the command and recognize whether it's a direction or verb noun or whatever.