I want to access "sudoers" file and also access "su -" but I fail and get following error please check terminal output that I have tried. I am m-usman(admin) but not allow to edit or access ? :(
m-usman@muhammad-usman:~$ sudo gedit /etc/sudoers
[sudo] password for m-usman:
m-usman is not in the sudoers file. This incident will be reported.
m-usman@muhammad-usman:~$ su -
Password:
su: Authentication failure
m-usman@muhammad-usman:~$ sudo visudo
[sudo] password for m-usman:
m-usman is not in the sudoers file. This incident will be reported.
How can I fix it?