Is this the best site to be asking about the Android command line? Because many of the commands are different than on my Unix-like system.
It depends a little. IMHO it is clearly on-topic as long as it is user-oriented (and not development-oriented), even it might be a "power-user's terrain". And even more on-topic if it's clearly something Android specific (as you've already indicated, many commands are "a little different", e.g. not all options are available to them).
But as you've asked for "the best site", there's also a second point to consider: If it's a generic quesion on available commands, or how to deal with things like redirecting output, piping, listing directories etc., that might fit better on either Unix & Linux or Super User (at least you should check the questions there before, as you might find yours already answered).
I would have to say that this is definitely the right place to be asking about the command line, especially when it is Android specific.