apt - E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) finally fixed

I was configuring my local Ubuntu installation (14.04 LTS). I got this error while trying to run apt-get. I have seen many answer regarding this issue. None of a single answer solve my issue. So I have decided to post a question even many duplicates exists. See my answer below.

I post my answer without editing my question because most of us like me only see the answer section. So here how I fixed my issue:

I was using 2 terminal and I forgot that I was installing another software while trying to run another apt-get (installing on Ubuntu Software Center will cause the same), so I wait until the installation completed. After that no error occurred.

If this is not one your case then you can follow other answer:

1. Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?


2. Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?

Hope this will help others.