django development server, how to stop it when it run in background

One liner..

pkill -f runserver

The answer is findable via Google -- and answered in other forums. Example solution is available on the Unix & Linux StackExchange site.

To be explicit, you could do:

ps auxw | grep runserver

This will return the process and its respective PID, such as:

de        7956  1.8  0.6 540204 55212 ?        Sl   13:27   0:09 /home/de/Development/sampleproject/bin/python ./manage.py runserver

In this particular case, the PID is 7956. Now just run this to stop it:

kill 7956

And to be clear / address some of the comments, you have to do it this way because you're running the development server in the background (the & in your command). That's why there is no "built-in" Django stop option...