usermod

At times you will need to modify user accounts which may be done with this command.

Options
-L lock a password

-U unlock a password

This command will enable you to use many of the same commands as those found in useradd. For example you may use this command to add a comment to a username.

usermod -c "Tech Guy" joe

If you had created a user password and wanted to lock it you could use this command:

usermod -L joe