When I wanted to execute
hadoopmaster@dhruvhadoop3-HP-Compaq-dc5800-Small-Form-Factor:~$ sudo gedit ~/.bashrc
It gave me the following error
sudo: unable to resolve host dhruvhadoop3-HP-Compaq-dc5800-Small-Form-Factor
[sudo] password for hadoopmaster:
hadoopmaster is not in the sudoers file. This incident will be reported.
Its about the /etc/sudoers.If you simply want have sudo access then add you user to the group sudo via usermod -aG sudo username. This will add the group sudo to the user username (Keep in mind that you need root access to execute usermod). For more information look here.
Your second error message indicates that there is anything wrong with your hostname (Click here for help. And you should not need root access to edit ~/.bashrc.
gksudoand friends to run graphical applications as super-user. See What is the difference between “gksudo nautilus” and “sudo nautilus”? – David Foerster Oct 18 '15 at 10:55pkexecthe replacement forgksudo. – Marton Oct 18 '15 at 19:15