os.system easy question

[Erno Kuusela]

In article <slrn96qrgp.gg.huwdotlynes at Marvin.ic.ac.uk>,
huwdotlynes at ic.ac.uk (Huw Lynes) writes:

| how to kill the 
| external program after it has run. Or alternatively how to
| run an external program in such a way that the script will
| not halt.

do something like...

import signal, os

class BgProc:
    def __init__(self, cmdline):
        pid = os.fork()
        if pid > 0:
            self.pid = pid
        else:
            try:
                os.execvp('/bin/sh', ['sh', '-c', cmdline])
            finally:
                os._exit(255)

    def wait(self):
        return os.waitpid(self.pid, 0)

    def kill(self, sig = signal.SIGTERM):
        os.kill(self.pid, sig)
        return self.wait()

  -- erno