chguserpw.php is meant for the
users to change their own password. To do that, there is a readymade
.desktop-file, that will launch the script in the default
web-browser, with the username of the current user as an
argument. Then the user will need to enter the old password once,
and the new password twice.
If for any reason an admin needs to help the user in doing this,
and the admin for an unknown reason know the users password, then
the admin might search up the user, and enter the old password
together with the new password twice.