Mine

import os, traceback, sys

class ExternalCommandErrorWithOutputList(Exception):
    def __init__(self,args=None):
        if args:
            self.args = args[0]
            self.outputList = args[1]
        else:
            self.args = args
            self.outputList = []


def executeCommandReturnOutput(args):
    args_str = ' '.join(args)

    if os.name not in ['nt', 'os2']:
        import popen2
        p = popen2.Popen4(args_str)
        p.tochild.close()
        outputList = p.fromchild.readlines()
        exitCode = p.wait()
        if exitCode == 0:
            exitCode = None
        else:
            exitCode >>= 8
    else:
        i,k = os.popen4(args_str)
        i.close()
        outputList = k.readlines()
        exitCode = k.close()
        
    if exitCode is not None:
        raise ExternalCommandErrorWithOutputList, [exitCode, outputList]

    return outputList


if __name__ == "__main__":
    for cmd in [['python', '-c', '"print 5"'],
                ['python', '-c', '"1/0"'],
                ['python', '-c', '"print 6;import sys;sys.stdout.flush();print >>sys.stderr, 7;print 8"']]:
        try:
            ret = executeCommandReturnOutput(cmd)
            print 'ret', ret
        except executeCommandReturnOutput, e:
            print 'executeCommandReturnOutput', e, e.outputList
        except Exception, e:
            print 'Exception', e
            type, value, stack = sys.exc_info()
            print ''.join(traceback.format_exception(type, value, stack))
        except:
            print 'except'
            type, value, stack = sys.exc_info()
            print ''.join(traceback.format_exception(type, value, stack))
        else:
            print 'else'
        print '*' * 20