After editing login.defs, common-auth, and common-password I am unable to login.
The goal was to set password restrictions ...
I then used recovery mode and I restored the login.defs and common-auth and common-password files to their old settings, but was still not able to login. I tried adding a new user and the user was created but the new user cannot login. I think I have hosed PAM somehow, the failure is silent (will look at system logs).