Fix machine hostname return null as it value

If your getting null value as your host name, check that both /etc/hosts and /etc/hostname files has the same name to the host, If not put the same name to both file as hostname, Here[1] you can find how to do that.

[1]http://shameerarathnayaka.blogspot.com/2013/03/how-to-change-machine-name-in-ubuntu.html