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Unit 11: User Accounts

11.1.4 How to Delete users? notes

The userdel command is used to remove the user’s record from the /etc/passwd and /etc/
shadow used in the login process. The command has a single argument, the username.
[root@bigboy tmp]# userdel paul
There is also an optional -r switch that additionally removes all the contents of the user’s home
directory. Use this option with care. The data in a user’s directory can often be important even
after the person has left your company.

[root@bigboy tmp]# userdel -r paul
11.1.5 How to tell the groups to which a user Belongs?

Use the groups command with the username as the argument.

[root@bigboy root]# groups paul
paul : parents
[root@bigboy root]#

11.1.6 How to change the ownership of a file?

You can change the ownership of a file with the chown command. The first argument is the
desired username and group ownership for the file separated by a colon (:) followed by the
filename. In the next example we change the ownership of the file named text.txt from being
owned by user root and group root to being owned by user testuser in the group users:

[root@bigboy tmp]# ll test.txt
-rw-r--r-- 1 root root 0 Nov 17 22:14 test.txt
[root@bigboy tmp]# chown testuser:users test.txt
[root@bigboy tmp]# ll test.txt
-rw-r--r-- 1 testuser users 0 Nov 17 22:14 test.txt
[root@bigboy tmp]#
!

Caution You can also use the chown command with the -r switch for it to doe recursive
searches down into directories to change permissions.

11.1.7 using sudo

If a server needs to be administered by a number of people it is normally not a good idea for them
all to use the root account. This is because it becomes difficult to determine exactly who did what,
when and where if everyone logs in with the same credentials. The sudo utility was designed to
overcome this difficulty.
The sudo utility allows users defined in the /etc/sudoers configuration file to have temporary
access to run commands they would not normally be able to due to file permission restrictions.
The commands can be run as user “root” or as any other user defined in the /etc/sudoers
configuration file. The privileged command you want to run must first begin with the word sudo
followed by the command’s regular syntax.
When running the command with the sudo prefix, you will be prompted for your regular
password before it is executed. You may run other privileged commands using sudo within a

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