SU Command and SUDO Command in Linux


SU = Substitute User

If any user needs to log in as another user in the same Command Line Interface CLI (shell)


In some cases where a normal user wants to execute a command(that can normally be executed only by root) if the local system administrator(root) is not available, sharing the root’s password is not advisable, so sudo command can be used

Eg:su -l user-name

  1. The root user can log in any account without needing the password of the other users.
  2. A normal user only log in as any of the other users with a password.



To execute any command with root privilege – prepend sudo in front of the command

Eg: sudo useradd testuser

but, not all the users are in sudo users by default.

To Make a SUDO user a in RHEL

Add a user to the wheel group

usermod -aG wheel testuser

Now test user can execute any command with root privilege without needing the root password

and all the commands that are executed by a sudo user will be logged in a file/var/log/secure

if the non-sudo user tries to give any command it will be sending the report as a mail(auto-generated) to root.

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