Python execute command line,sending input and reading output

Question

How to achieve the following functionality:

Python executes a shell command, which waits for the user to input something
after the user typed the input, the program responses with some output
Python captures the output

Take a look at [subprocess module](http://docs.python.org/library/subprocess.html). — RanRag, May 20 '12 at 12:02
In a more general case [pexpect](http://www.noah.org/python/pexpect/) might be useful. — jfs, May 20 '12 at 12:23

score 12 · Accepted Answer · answered May 20 '12 at 12:03

12

You probably want subprocess.Popen. To communicate with the process, you'd use the communicate method.

e.g.

process=subprocess.Popen(['command','--option','foo'],
                         stdin=subprocess.PIPE,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE)
inputdata="This is the string I will send to the process"
stdoutdata,stderrdata=process.communicate(input=inputdata)

answered May 20 '12 at 12:03

mgilson

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3

What if i have 2 or more inputs and i want to run it in background so that i should see no console. – Nikhil.Nixel May 28 '18 at 06:34

score 1 · Answer 2 · answered Feb 04 '22 at 10:48

For sync behaviors, you can use subprocess.run() function starting from Python v3.5.

As mentioned in What is the difference between subprocess.popen and subprocess.run 's accepted answer:

The main difference is that subprocess.run executes a command and waits for it to finish, while with subprocess.Popen you can continue doing your stuff while the process finishes and then just repeatedly call subprocess.communicate yourself to pass and receive data to your process.

Python execute command line,sending input and reading output

2 Answers2

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