Python subprocess block

I'm having a problem with the module subprocess; I'm running 开发者_如何学编程a script from Python:

subprocess.Popen('./run_pythia.sh', shell=True).communicate()

and sometimes it just blocks and it doesn't finish to execute the script. Before I was using .wait(), but I switched to .communicate(). Nevertheless the problem continues.

First the script compiles a few files, then it execute into a file:

run_pythia.sh:

#!/bin/bash
#PBS -l walltime=1:00:00

./compile.sh
./exec > resultado.txt

compile.sh:

O=`find ./ -name "*.o" | xargs`

# LOAD cernlib2005
module load libs/cernlib/2005

# Compile and Link
FC=g77
CERNLIBPATH="-L/software/local/cernlib/2005/lib -lpacklib"

$FC call_pyth_mix.f analise_tt.f $O $CERNLIBPATH -o exec

Is the script you execute, is run_pythia.sh guaranteed to finish executing? If not, you might not want to use blocking methods like communicate(). You might want to look into interacting with the .stdout, .stderr, and .stdin file handles of the returned process handle yourself (in a non-blocking manner).

Also, if you still want to use communicate(), you need to have had passed subprocess.PIPE object to Popen's constructor arguments.

Read the documentation on the module for more details.

Maybe you can try to do a trace on it:

import pdb; pdb.set_trace()