Question

I want to create a subprocess with popen.
The special demand is to use shell direction in the command.

args = [
    '/bin/cat',
    '<',
    'textfile',
    ]
process = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                           env={'LANG':'de_DE@euro'})
processpid = process.pid
output = process.communicate()

I do not want to use the shell=True option, therefore here my question to you, how to implent it.

Regards
Stefan

Answer 1

Impossible unless the program you’re calling implements redirection itself (which cat doesn’t). To use shell features, you have to pass shell=True or invoke a shell explicitly.

OTOH, if you just want to read from textfile, you could pass it as the subprocess’s stdin:

subprocess.Popen(args,
                 stdin=open("textfile"),
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
                 env={'LANG':'de_DE@euro'})