Changing a user's password can be done from the console by using the
Only root can change the password for another user with the
passwd command. When the command is entered, you will
be prompted to enter, then confirm, the password you are setting. If they
match, then the user tokens are updated and the password is changed. A
user can also change his own password from the console by typing
passwd; in this case, the user is prompted for his old password
prior to entering the new one.
Most Linux distributions install with a password cracker module activated for password changes. This module will test a password to see if it follows good password practices. If not, a warning will be given that the user is using a bad password. Depending on your configuration, a user may be required to use a secure password before it will be accepted. Root may be warned when a password is set, but the action cannot be stopped.
In Webmin, a password is changed using the "Change Passwords" module from the System section. Select a user from the list and enter the new password into the blanks.
From the console, users are deleted using the
userdel -r userid
The optional -r switch will delete the user's home directory and all its contents in addition to the user. If the directory is to be preserved, omit the -r switch. This switch will not automatically delete all the files on the system that belong to the user, just the home directory.