Visudo is needed to make modifications to the sudoers file. In a fresh install of CentOS "sudoers" file is not normally found. To install visudo issue the command $ yum -y install sudo As a sys admin, you need to be careful when performing tasks with root privileges. To be cautious, you can create a new user and assign him with root privileges using "visudo" $ /usr/sbin/visudo # User privilege specification root ALL=(ALL) ALL test ALL=(ALL) ALL In the above file, test is a new user created with root privileges. In order for the "test" user to have root privileges, command "sudo" should be used. It prevents the user from issuing any commands that can cause system wide havoc and it also logs the command inside "/var/log/secure" for review

The help pages state ... su - run a shell with substitute user and group id's sudo - execute a command as another user (or root) When 'sudo' is used with a command, the command gets executed with privileges set for the user and the group she belongs to. If a password is required and if it is given initially, the session will be valid depending on the time set for each session and the user needn't have to type the password within that duration. /etc/sudoers is the location where permission settings for sudoers are being set. (more…)