Changing user properties

There are a few commands for changing various properties of an account (i.e., the relevant field in /etc/passwd):

The super-user may use these commands to change the properties of any account. Normal users can only change the properties of their own account. It may sometimes be necessary to disable these commands (with chmod) for normal users, for example in an environment with many novice users.

Other tasks need to be done by hand. For example, to change the username, you need to edit /etc/passwd directly (with vipw, remember). Likewise, to add or remove the user to more groups, you need to edit /etc/group (with vigr). Such tasks tend to be rare, however, and should be done with caution: for example, if you change the username, e-mail will no longer reach the user, unless you also create a mail alias. [1]