[Linux 常見問題] Find and kill a process in one line using bash and regex

 Source From Here

Question
I often need to kill a process during programming.

The way I do it now is:

[~]$ ps aux | grep 'python csp_build.py'
user 5124 1.0 0.3 214588 13852 pts/4 Sl+ 11:19 0:00 python csp_build.py
user 5373 0.0 0.0 8096 960 pts/6 S+ 11:20 0:00 grep python csp_build.py
[~]$ kill 5124

How can I extract the process id automatically and kill it in the same line?

Like this:

[~]$ ps aux | grep 'python csp_build.py' | kill <regex that returns the pid>

HowTo
In bash, you should be able to do:

# kill $(ps aux | grep '[p]ython csp_build.py' | awk '{print $2}')

Details on its workings are as follows:

* The ps gives you the list of all the processes.
* The grep filters that based on your search string, [p] is a trick to stop you picking up the actual grep process itself.
* The awk just gives you the second field of each line, which is the PID.
* The $(x) construct means to execute x then take its output and put it on the command line. The output of that ps pipeline inside that construct above is the list of process IDs so you end up with a command like kill 1234 1122 7654.