How to kill a running iPython process

Question

I'm using iPython to control some other equipment connected to my Mac. Most of the time it runs fine, but sometimes I gave a wrong command to the equipment, iPython is just hanging forever since it's waiting for a response but won't get one, so I need a way to kill the iPython process. ctrl+c doesn't do anything, it just prints a ^C string on the screen. ctrl+z can get me out of iPython, but it doesn't seem to kill it, because when I restart iPython I can't re-establish the communication with the equipment. Eventually I had to restart my computer to get the two talking again.

Answer 1

ctrl+z can get me out of iPython, but it doesn't seem to kill it, because when I restart iPython I can't re-establish the communication with the equipment. Eventually I had to restart my computer to get the two talking again.

Assuming you're using bash (the default shell for OS X), the ^Z turns it into a suspended background job, and you can use job control to kill it:

$ ipython
Python 2.7.5 (default, Mar  9 2014, 22:15:05)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] on darwin
IPython 2.1.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]:
[2]+  Stopped                 ipython
$ kill %2

[2]+  Stopped                 ipython
$

[2]+  Terminated: 15          ipython
$

A couple of things to notice there:

• Usually the backgrounded program will be job 1, but you can't rely on that. Look at the [2]+ Stopped ; that tells you that it's job 2, so you need kill %2 , not kill %1 .
  • (I deliberately put another job in the background to make it 2 for demonstration purposes.)
  • If you're not sure which job you want to kill, use the jobs command to list them all.
  • Or you can use %ipython , which refers to the first job whose name starts with ipython .
  • Or %% , which means the "current" job—if you haven't done anything since the ^Z , that'll be ipython , but if you've done a bunch of other stuff since then and aren't sure if you affected job control, be careful.
• Although the kill %2 kills the task immediately, bash may not recognize that until the next prompt; notice that I had to hit return an extra time before seeing the Terminated message.
  • In some situations, you'll need to use the wait command.
• If IPython is very badly hung and not responding to signals properly, use kill -9 %2 .
• If you hit ^Z by mistake and don't want to kill the job, use fg %2 instead of kill %2 to get back into IPython .
• If you want to let IPython run in the background while you do other things, use bg %2 instead of kill %2 . (You can always fg or kill it later (or disown it, or various other things—see the linked guide.)

Answer 2

In the Terminal find out the process id using the "top" command. It is the PID column, and under the COMMAND column you will see IPython, or something similar. Them run kill -9 PID