User Access and User ID Commands in UNIX

Introduction UNIX is a multiuser system, means more than one user can work on the UNIX machine at a time. Every user has his own user login and password. User access and id commands include command through which user can Login into his account Logout of his account Change his login account password

Logging in the System To login into the system user enters his login and password which is asked at the starting up of the system LOGIN: PASSWORD: The super user login is root Every user has a login password If any of these goes wrong system says login wrong and user has to enter both the entries again

Logging out of the System To logout of his login account user uses the command logout Or Ctrl + d Or types exit * Only user’s login account is closed but the system is still running

Changing password To change his login password user uses the command passwd enter old password: enter new password: reconfirm new password: User can change password for his login account only Super user can change password for other users also by using command passwd user_login_name and the system will ask for the new password and then reconfirm it. Even the superuser does not what users passwd is