Need a quick place to test something basic out? Here is the link for a nice little nix emulator.
It supports the following commands:
? @ alias bc break brow bye cat cd chmod clear compress continue cp cut d date df echo eval exit fg foreach fw fy goto grep icq id if jzip kill ln load ls mail man mkdir mkfifo more mount mv ping ps pwd read rehash repeat rm rmdir save scan sed set shift source su tail tee touch unalias uname unhash unmount unset vi wc where while whoami wish
For a large list of free shell accounts, please visit http://shells.red-pill.eu/