"sudo" Command and Privilege

Linux Tutorials - Herong's Tutorial Examples

∟"sudo" Command and Privilege

This section 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. You need to make sure that the "wheel" group has the sudo privileges defined in the /etc/sudoers file.

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

root# grep wheel /etc/sudoers
%wheel  ALL=(ALL)  ALL

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)

3. Running commands as non-root users using "sudo -u" option. The following example shows that "apache" does not have permission to run the "conda" program.

herong$ sudo -u apache /usr/local/anaconda3/bin/conda
  [sudo] herong password:
  sudo: /usr/local/anaconda3/bin/conda: Permission denied

4. Removing the "sudo" privilege by removing 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

Memory 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

System Users and Groups

Add Users and Groups Manually

File Systems

Block Devices and Partitions

LVM (Logical Volume Manager)

Installing CentOS

SELinux - Security-Enhanced Linux

Network Connection on CentOS

Internet Networking Tools

SSH Protocol and ssh/scp Commands

Software Package Manager on CentOS - DNF and YUM

vsftpd - Very Secure FTP Daemon

LDAP (Lightweight Directory Access Protocol)

Administrative Tasks

References

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