Now the shorten algorithm creates a shallow copy of perso and use it instead of the previous one.

It then removes the shallow file to allow pull/push and clone from it.
Addition of prev in the possible previous keywords
Addition of the sudo_which script that launches sudo on a command making sure to give the full path to sudo.

This way I can call 'sudo something' while something is in the PATH of the user but not in the PATH of root.