[txutxu]

The command= simply changes "what" gets executed when the user logs in.

A jail (ChrootDirectory in ssh) changes "where" the user gets when logs in.

The most creative thing I've do with command= was a "select" menu in bash (with some actions in the shudoers).

Other interesting tool I've discovered recently is rrsync. I'm doing the backups of my systems isolated with this. It's distributed with the rsync sources, you put it like:

    command="rrsync /path/to/chroot/the/remote/rsync/client/"

[stock_toaster]

I used to use rsnapshot with command= set to a custom script that would let a few things through (rsync being one of them), by instrospecting `$SSH_ORIGINAL_COMMAND`.