killing a script

Nobody nobody at nowhere.com
Mon Aug 29 08:52:46 CEST 2011


On Sun, 28 Aug 2011 18:15:56 -0700, Russ P. wrote:

> Is there a
> simple way to ensure that the first Control-C will kill the whole darn
> thing, i.e, the top-level script? Thanks.

You might try using subprocess.Popen() or subprocess.call() rather than
os.system().

os.system() calls the platform's system() function. On Unix, this
specifically ignores SIGINT and SIGQUIT for the duration of the call,
ensuring that Ctrl-C and Ctrl-\ only affect the child process and not the
parent.

subprocess.Popen() doesn't perform any implicit signal handling; it's
implemented in Python in terms of os.fork() and os.execvp[e](). It also
has a better interface (i.e. you get to directly control the argument list
passed to the child process, rather than having to construct a shell
command and hope that you got the quoting/escaping correct).

This may not suffice if any of the descendent processes are moved into
their own process group, as signals generated by the tty driver are sent
only to the foreground process group. However, this is unlikely to be an
issue for simple non-interactive programs (e.g. standard Unix "commands").




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