[CentOS] Grant user permission with command line [edit sudoers file]

The command works on CentOS and Fedora only, and sample OS is CentOS version 7.0: 

Step 1

To grand permission to users, you need to edit your sudoers file, the command "visudo" is to open sudoers file to edit.

visudo

Step 2 

Press the key "i" to enter insert mode.

Step 3 

Scroll down on the line "## Allow root to run any commands anywhere", and add the user's name you want grand them permission:

## Allow root to run any commands anywhere
root                      ALL=(ALL)       ALL
exampleuser        ALL=(ALL)       ALL

Step 4

Press key "esc" and then type the command:

:wq

Reference:

http://blog.zwiegnet.com/linux-server/add-user-to-sudoers-group-centos/

https://www.digitalocean.com/community/tutorials/how-to-edit-the-sudoers-file-on-ubuntu-and-centos