Mac OS X Terminal - Basic commands not found by shell
To see if your $PATH variable is set:

echo $PATH


If you've set something to override it, it's likely in the files .bashrc or .bash_profile

You'll need to edit those to remove any entries overriding your $PATH variable.

Start with just mv them out the way (use /bin/mv to hit mv directly), and starting a new session to see if that fixes things.