Commands are of three forms:

1. VERB
2. VERB NOUN
3. VERB NOUN1 PREPOSITION NOUN2.

Examples:

1. INVENTORY, SCORE, WHO, EAST
2. EAT BANANA, HIT ZOMBIE, OPEN UMBRELLA, FOLLOW RAT, SHOUT "HI!"
3. KILL DWARF WITH AXE, OPEN DOOR WITH KEY, LIGHT STICK FROM FIRE, PUT TREASURE IN BAG.

Most of the time the nouns are objects (eg. UMBRELLA), but some commands expect strings, which are messages in quotes (eg. "HI!"). It doesn't really matter what preposition you use - F (short for FOR) is commonest. Adjectives shouldn't be used, and articles are ignored. If you try to OPEN KITCHEN DOOR you won't be understood - just OPEN DOOR; if you OPEN THE DOOR, you wasted your time typing the THE. Most commands, but direction commands in particular, can be strung together on one line, separated by dots or commas, eg. O.O.O.O.O.O.O will move you OUT seven times.