CentOS 6 - Add a user to sudoers

Here are steps in adding a user to sudoers in CentOS 6

1. Log on as root ( or switch to su with root password).
2. On the command window, do the following.
3. Enter "visudo". 
4. vi loads the sudoer file.
5. Look for %wheel in the sudoer file by entering " /%wheel "
6. Remove # from the line "#  %wheel  ALL=(ALL)  ALL" to enable the wheel group with same privileges as root.
7. Save and exit vi via  :wq.
8. To create a new user:
1. adduser   [new_user_name]
2. passwd    [new_user_name]   [password]
9. Use the usermod command to add the user to the wheel group:
1. usermod   -aG   wheel   [user_name]
10. Switch to the non-root user by entering "su  -  [user_name]"
11. Test by running a command that's allowed for root only.
    For example, /root is generally accessible only by root user. Try listing the content of /root. 
1. sudo  ls  -al  /root