create a tmp file for system execution

[Donn Cave]

Quoth Eric Texier <erict at millfilm.co.uk>:
| I have a py script executing a bunch of os.system in a loop.
| It is not very fast and I was wondering if it will not be better
| to recreate a execution file.
|
| My 2 questions:
|
| 1) what is faster for a big number of call
...
| os.system("csh -c 'source tmpFile' ")
| os.system("rm -f tmpFile")

You've already gotten some good answers, and you can answer
your own questions pretty easily just by trying the things
you propose to do.  Here are two more points:

-  this takes 4 seconds "wall clock" time on my computer:
     import os
     import string

     s = ['ls something somethingelse']*2000
     s.append('exit 17')
     s = string.join(s, '; ')
     t = os.system(s)

    (I added the "exit 17" just so I'd have some way to verify that
     it really did everything.)

-  If you have a file of commands, you don't need to "source" it,
   you can invoke the shell directly on the file - it's a "script".

-  Never use csh if you can avoid it, it's the worst of shells.
   The system() function uses "sh", and that's the right choice for
   most applications.

-  I'm assuming a UNIX platform.

	Donn Cave, donn at u.washington.edu