I am going to update packages in Ubuntu 22.04 terminal.
sudo apt update
But I get errors like this.
tester@ubuntu22.04-lts:~$ sudo apt update
[sudo] password for user:
tester is not in the sudoers file. This incident will be reported.
So, I am trying to add user to sudo group. But su command also encountered an error.
tester@ubuntu22.04-lts:~$ su
Password:
su: Authentication failure
I'm hesitating on how to deal with the problem.
I think "tester" user has been deleted from sudo group, is there any solution?
And here is one addition, it's as follows.
tester@ubuntu22.04-tls:~$ groups tester
tester : tester
