If you are facing error Like:
abhinav@EthicalHackx:~$ sudo /etc/init.d/smbd stop sudo: unable to resolve host EthicalHackx: Resource temporarily unavailable
Here is how to Solve this error when doing sudo
Your Host Name is not present in you Hosts file after you changed it, so just add it in Hosts file located at /etc/hosts and also at /etc/hostname with the familiar structure of hosts file like in example below.
Your /etc/hosts and /etc/hostname will be like this after you add it.
$ cat /etc/hostname
$ cat /etc/hosts
Restart your system and the error is gone forever.