Python os.system() input text to script

Question

I have a script that I need to automate, so it's a .sh script which I want to run inside a python script: something like this:

import os
os.system('./script.sh -p 1234')

The script script.sh needs the user to input 3 fields, 1) the sudo password, 2) a string and 3) a string.

Enter password for user: xxxx  #typed by me
Enter Auth Username: xxxx      #typed by me
Enter Auth Password: xxx       #typed by me

How can I make the python script to type/insert/pass those 3 needed values to script.sh.

Solution

You can use subprocess.Popen to start the script and the communicate method to pass it input. Something like this:

import subprocess

p = subprocess.Popen(['./script.sh', '-p', '1234'], 
                     stdin=subprocess.PIPE, stdout=subprocess.PIPE)
stdout, stderr = p.communicate(input='password\nauth username\nauth password\n')

Comments

[PepperoniPizza]

I tried this, it seems to work, but I cannot tell because I can't see the script output, If I run the process with os.system() I can see the output on the python shell, nayway to get this ?

[larsks]

Do you see the line where it says, stdout, stderr = p.communicate(...)? stdout contains the output from the script.

[larsks]

The subprocess documentation has more details about how everything works.

[PepperoniPizza]

could you please explain me why the password\nauth ?

[larsks]

\n is a newline character. Each \n is simulating you hitting the return key.

[larsks]

The first response is "password", the second response is "auth username", the third response is "auth password". The \n is simply where you would hit "return" if you were typing this manually.