Making 'git pull' work with Github

As I'm using Github from different computers, I want to update my local repositories from Github. But git pull wasn't working out of the box and wants to know more information about.

You asked me to pull without telling me which branch you
want to merge with, and 'branch.master.merge' in
your configuration file does not tell me, either. Please
specify which branch you want to use on the command line and
try again (e.g. 'git pull <repository> <refspec>').

Executing the lines below in your repository will make it work as expected and you're able to use git pull.

git config branch.master.merge refs/heads/master
git config branch.master.remote origin