CertiGuide to A+ (A+ 4 Real)  9  Chapter 5: The Linux Operating System       9  Command Line Functions And Administrative Utilities            9  User Management Commands

w and who - Who is Logged in and What They are Doing 1 whoami - Print Effective UserID

System administrators should never use the root account as their default log in account. If only for the simple reason that running a command with the wrong set of meta characters (wild cards) will do much less damage with the permission set of their user account than from the root account. For example the command:

rm -r /*

Entered from a user account would have little affect on the system other than the user may lose most of his or her files, however consider the impact of running a command like this from the root account. Virtually every file and directory on the system will be deleted. This is one simple reason and administrator should always use their own account as their default account and then use the su command to become root for the period time that they need to perform administrative functions and when finished return to their own account. By entering:

su -

The user will be prompted for a password and after entering the root password, a new shell is opened under the userID of root and with all of the root account’s privileges. Root can be exited through the normal process of typing either exit or logout.

If necessary root can become any system user by typing:

su userid

No password will be necessary when changing from the root account to another user account.

w and who - Who is Logged in and What They are Doing 1 whoami - Print Effective UserID