pwdutils is a collection of utilities to manage
the passwd and shadow user information. The
difference to the shadow suite is that these
utilities can also modify the information stored
in NIS, NIS+, or LDAP. PAM is used for user
authentication and changing the pasword. It
contains passwd, chage, chfn, chsh, chpasswd,
expiry, gpasswd, grpck, groupadd, groupdel, groupmod, grpunconv, newgrp, pwck, pwconv, pwunconv, useradd, userdel, usermod, vipw, and a daemon for changing the password on a remote machine over a secure SSL connection. The daemon also uses PAM, so it can change passwords no matter where they are stored.
