get pid of a nohup command in Python

[g.willgoose]

I'm new to Python and am evaluating moving a project from Tcl/Tk to
Python and am stuck on one issue. How can I nohup (or any detached
task for that matter) a process and get its PID in Python. The obvious
route of (with a trivial example)

os.system("nohup ls > junk &")

returns the status of the command execution (ie. 0). I wish to get the
PID output of the command (e.g. 16617). All the other commands spawn**
also seem to return the execution status not the PID. This is a
showstopper so any help appreciated.

 

[Gabriel Genellina]

I'm new to Python and am evaluating moving a project from Tcl/Tk to
Python and am stuck on one issue. How can I nohup (or any detached
task for that matter) a process and get its PID in Python. The obvious
route of (with a trivial example)

os.system("nohup ls > junk &")

returns the status of the command execution (ie. 0). I wish to get the
PID output of the command (e.g. 16617). All the other commands spawn**
also seem to return the execution status not the PID. This is a
showstopper so any help appreciated.

The spawn* family will return the pid if you use the P_NOWAIT flag.
But the best way is to use the subprocess module; Popen objects have a pid
attribute.

http://docs.python.org/lib/module-subprocess.html