Program initiated via python's os.system() doesn't work (when in crontab script)

itmi · 03-03-2008, 05:12 AM

Hello, dear community

Please help if you know the answer for the following problem: How can i specify custom variables to be recognized by programs which are executed by "os.system()" in python?

I have a python script which executes several programs via os.system() call. It runs fine when i execute it manually from interactive shell (bash), but when i put it in crontab it some of those programs don't work since they don't find several special environment variables that are present in my .bashrc file.

Trying to figure the problem out i have put two lines in the beginning of my crontab file, so that it looks like this:

Code:

SHELL=/bin/bash
USER=misha
*/30 * * * * /opt/sevzapmodis/pymodis.py >> /home/misha/pymodis.log

but it didn't help. Any ideas what could be the solution?

Guttorm · 03-03-2008, 08:56 AM

Hi

The file .bashrc is usually for interactive shells. Mine starts with:

Code:

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

So sourcing it will not work. But why not add the special environment variables to start the crontab?

Code:

SHELL=/bin/bash
USER=misha
SOMESPECIALVARIABLE=SomeValue
*/30 * * * * /opt/sevzapmodis/pymodis.py >> /home/misha/pymodis.log

itmi · 03-03-2008, 01:08 PM

Thanks, Guttorm. I've tried it exactly the way you have suggested, but it didn't work somehow. Next step was to set via "os.environ[]" but with the same negative result.

For now i have resolved it via assigning variables right in that (sub)script invoked by python, but i am still confused why it doesn't work the way Guttorm suggests...

chrism01 · 03-03-2008, 05:36 PM

Try this: http://www.adminschoice.com/docs/cro...tm#Environment