Is there an equivalent to CTRL C in IPython Notebook in Firefox to break cells that are running

Question

I ve started to use the IPython Notebook and am enjoying it  Sometimes  I write buggy code that takes massive memory requirements or has an infinite loop  I find the  interrupt kernel  option sluggish or unreliable  and sometimes I have to restart the kernel  losing everything in memory   I also sometimes write scripts that cause OS X to run out of memory  and I have to do a hard reboot  I m not 100  sure  but when I ve written bugs like this before and ran Python in the terminal  I can usually CTRL C my scripts   I am using the Anaconda distribution of IPython notebook with Firefox on Mac OS X

User · Answer

You can press I twice to interrupt the kernel   This only works if you re in Command mode  If not already enabled  press Esc to enable it

User · Answer

UPDATE  Turned my solution into a stand-alone python script   This solution has saved me more than once  Hopefully others find it useful  This python script will find any jupyter kernel using more than cpu threshold CPU and prompts the user to send a SIGINT to the kernel  KeyboardInterrupt   It will keep sending SIGINT until the kernel s cpu usage goes below cpu threshold  If there are multiple misbehaving kernels it will prompt the user to interrupt each of them  ordered by highest CPU usage to lowest   A big thanks goes to gcbeltramini for writing code to find the name of a jupyter kernel using the jupyter api  This script was tested on MACOS with python3 and requires jupyter notebook  requests  json and psutil   Put the script in your home directory and then usage looks like   python   interrupt bad kernels py Interrupt kernel chews cpu ipynb  PID  57588  CPU  2 3    y n  y   Script code below   from os import getpid  kill from time import sleep import re import signal  from notebook notebookapp import list running servers from requests import get from requests compat import urljoin import ipykernel import json import psutil   def get active kernels cpu threshold          Get a list of active jupyter kernels         active kernels          pids   psutil pids       my pid   getpid        for pid in pids          if pid    my pid              continue         try              p   psutil Process pid              cmd   p cmdline               for arg in cmd                  if arg count  ipykernel                        cpu   p cpu percent interval 0 1                      if cpu  gt  cpu threshold                          active kernels append  cpu  pid  cmd           except psutil AccessDenied              continue     return active kernels   def interrupt bad notebooks cpu threshold 0 2          Interrupt active jupyter kernels  Prompts the user for each kernel          active kernels   sorted get active kernels cpu threshold   reverse True       servers   list running servers       for ss in servers          response   get urljoin ss  url   replace  localhost    127 0 0 1     api sessions                           params   token   ss get  token                 for nn in json loads response text               for kernel in active kernels                  for arg in kernel -1                       if arg count nn  kernel    id                             pid   kernel 1                          cpu   kernel 0                          interrupt   input                               Interrupt kernel     PID      CPU        y n    format nn  notebook    path    pid  cpu                           if interrupt lower       y                               p   psutil Process pid                              while p cpu percent interval 0 1   gt  cpu threshold                                  kill pid  signal SIGINT                                  sleep 0 5   if   name         main         interrupt bad notebooks

User · Answer

I could be wrong  but I m pretty sure that the  interrupt kernel  button just sends a SIGINT signal to the code that you re currently running  this idea is supported by Fernando s comment here   which is the same thing that hitting CTRL C would do  Some processes within python handle SIGINTs more abruptly than others    If you desperately need to stop something that is running in iPython Notebook and you started iPython Notebook from a terminal  you can hit CTRL C twice in that terminal to interrupt the entire iPython Notebook server  This will stop iPython Notebook alltogether  which means it won t be possible to restart or save your work  so this is obviously not a great solution  you need to hit CTRL C twice because it s a safety feature so that people don t do it by accident   In case of emergency  however  it generally kills the process more quickly than the  interrupt kernel  button

User · Answer

Here are shortcuts for the IPython Notebook    Ctrl-m i interrupts the kernel   that is  the sole letter i after Ctrl-m   According to this answer  I twice works as well

User · Answer

To add to the above  If interrupt is not working  you can restart the kernel    Go to the kernel dropdown    restart    restart and clear output  This usually does the trick  If this still doesn t work  kill the kernel in the terminal  or task manager  and then restart   Interrupt doesn t work well for all processes  I especially have this problem using the R kernel

[python] Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?

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