As a Linux Administrator, there will be times where you will want to require a user to change their password at next login.
A great example of this is after setting up a new user with a generic password.
To require or force a user to change their password at next or even their first login, login as root or use sudo to run the following command (this is withe the capital O flag):
chage -d -O username
Or, you may also user (that’s the zero flag)
chage -d 0 username
Substitute username with the actual user’s name of course.
At the user’s next login, they will be required to enter their current password and set a new password.