I had an interesting issue arise where I sent a computer to a customer located in Germany. I had created a password for them, but they had problems logging in with it. It turns out that the password I had created contained the letters Z and Y. These two keys are swapped on German keyboards so when they plugged in their own German keyboard they ended up entering the wrong password as the computer was still set to the English keyboard layout.
I have looked into the most common keyboard layouts used in Europe (QWERTY, QWERTZ & AZERTY) and you can avoid key swapping problems like mine if you avoid using the letters Z, Y, A, Q, M & L in any password or user name.
Update. Here is a simple one liner to generate a random alpha numerical password of 8 characters that avoids these letters. You can of course change the password length by changing the -c switch on the head call. This should work on any *nix based system (including MacOS X) that has openssl installed. One warning is the password will visible at generation time to other local users on shared systems if the other users are watching for process list changes. This doesn’t matter to me too much as I generate the passwords on my Mac laptop, but it is something to keep in mind if you are on an shared system.
openssl rand -base64 25 | tr -dc 'BCDEFGHIJKNOPRSTUVWXbcdefghijknoprstuvwx0123456789' | head -c8; echo ""