How do I pass a string into subprocess.Popen (using the stdin argument)?

Question

If I do the following:

import subprocess
from cStringIO import StringIO
subprocess.Popen([\'grep\',\'f\'],stdout=subprocess.PIPE,stdin=StringIO(\'one\\ntwo\\         


        

Answer 1

There's a beautiful solution if you're using Python 3.4 or better. Use the input argument instead of the stdin argument, which accepts a bytes argument:

output = subprocess.check_output(
    ["sed", "s/foo/bar/"],
    input=b"foo",
)

This works for check_output and run, but not call or check_call for some reason.