If a filename is given, a log of the game is written onto that file. If the -a flag is given before the filename, that file is appended to, not truncated.
The game will ask you what length game you would like. Valid responses are ``short'', ``medium'', and ``long''. You may also type ``restart'', which restarts a previously saved game. You will then be prompted for the skill, to which you must respond ``novice'', ``fair'', ``good'', ``expert'', ``commodore'', or ``impossible''. You should normally start out with a novice and work up.
In general, throughout the game, if you forget what is appropriate the game will tell you what it expects if you just type in a question mark.
/usr/share/doc/usd/31.trek