"sudo" Command and Privilege

Provides a tutorial example on how to grant 'sudo' privilege to a user to allow him/her to run 'sudo' command to gain 'root' permission without login as 'root'.

What Is "sudo" Command? "sudo" command allows to temporarily run a command with "root" administrative right. The basic syntax of the "sudo" command is:

sudo [sub-command]

The above command will prompt for your password. Once provided, the system runs the given sub-command under the "root" permission. This is a much safer way than login as "root" to run the given sub-command.

In order to run "sudo" command, the user must be granted with the "sudo" privilege first. This can be done in different ways.

1. Adding the user to the "wheel" group on RedHat, CentOS and similar systems:

(login as root)
root# usermod -aG wheel herong

2. Adding the user to the "sudo" group on Debian, Ubuntu and similar systems:

(login as root)
root# usermod -aG sudo herong

You can verify your sudo privilege by running the "sudo id" command.

(login as herong)
herong$ id
  uid=1000(herong) gid=1000(herong) groups=1000(herong),10(wheel)...

herong$ sudo id
  (enter herong's password)
    uid=0(root) gid=0(root) groups=0(root)

To remove the "sudo" privilege, you can remove the user from the "wheel" or "sudo" group.

herong$ sudo gpasswd -d joe wheel

herong$ sudo gpasswd -d joe sudo

Table of Contents

 About This Book

 Introduction to Linux Systems

 Cockpit - Web Portal for Administrator

 Process Management

 Files and Directories

Users and Groups

 Manage User Groups

 Group Access Permissions on Files

"sudo" Command and Privilege

 "adduser/usermod/userdel" - Commands to Manage Users

 File Systems

 Block Devices and Partitions

 LVM (Logical Volume Manager)

 Installing CentOS

 SELinux - Security-Enhanced Linux

 Network Connection on CentOS

 Software Package Manager on CentOS - DNF and YUM

 Running Apache Web Server (httpd) on Linux Systems

 Running PHP Scripts on Linux Systems

 Running MySQL Database Server on Linux Systems

 Running Python Scripts on Linux Systems

 vsftpd - Very Secure FTP Daemon

 Postfix - Mail Transport Agent (MTA)

 Dovecot - IMAP and POP3 Server

 Email Client Tools - Mail User Agents (MUA)

 LDAP (Lightweight Directory Access Protocol)

 GCC - C/C++ Compiler

 Graphics Environments on Linux

 Conda - Environment and Package Manager

 Tools and Utilities

 Administrative Tasks

 References

 Full Version in PDF/EPUB