This doesn't seem very feasible if you have more than one script on your system that makes use of any of those commands, especially if you didn't write them yourself. How would you tell each scripts about the passwords? Manually editing them? Seems like an awkward thing to do. It would be an even more awkward thing to explain in your script's instructions, if you were a script author. Plus by manually editing the scripts to add your password you would be storing your password in plaintext, bypassing the entire secure hashing deal. If your script had some kind of options dialog to simplify the process by storing it in a variable-- same issue there.
Basically this would make it so you could only manually type the command from the editbox-- which is the least important use case to protect from.
