run shell command using the subprocesses module of python

Question

I'm using Python 2.6. After checking the following link: Running shell command from Python and capturing the output Here is the code I plan to do:

    import subprocess

    # input: user email account
    # output: mailing list which contain the user as an owner
    def list_owners (usr_eml):
        p = subprocess.Popen(['/usr/lib/mailman/bin/find_member','-w'],
                             stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE,
                             stdin=subprocess.PIPE)
        out, err = p.communicate(usr_eml)
        print out
        m_list_usr_on = out.split( )

        print m_list_usr_on
    list_owners("my_email")

The output of this code is simply empty. On the other hand, if I run the code

/usr/lib/mailman/bin/find_member -w my_email directly from the shell command, I got the desired results. Could you explain to me the possible reasons of it? Thank you!

Answer 1

Try to add usr_eml after the -w:

import subprocess

# input: user email account
# output: mailing list which contain the user as an owner
def list_owners (usr_eml):
    p = subprocess.Popen(['/usr/lib/mailman/bin/find_member','-w',usr_eml],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE,
                         stdin=subprocess.PIPE)
    out, err = p.communicate()
    print out
    m_list_usr_on = out.split( )

    print m_list_usr_on
list_owners("my_email")