Type

type shows what kind of thing you're running, be it an alias, function, or binary program.

1type cmus

Whereis the Program

Ask where the angband program is, along with all its configuration files:

whereis angband

Also which shows where a binary file (the program) is,

1which cmus

Quick Search for Files

You'll need to set up locate for this by installing mlocate. mlocate needs a list of all files on the machine, so run:

1sudo updatedb

Then to find a file called 'my-cats.jpg', run:

1locate cats

For best results, run updatedb regularly, perhaps in crontab.