Questions tagged [subprocess]

The Python subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes.

If you want to run Python code in a separate process consider multiprocessing instead.

pexpect is preferable to subprocess in some cases.

Waiting for a command to finish and getting the result

• How to execute a program or call a system command? (check_call())
• Running shell command and capturing the output (check_output())
• How do I pass a string into subprocess.Popen (using the stdin argument)? (run(), .communicate())
• How do I use subprocess.Popen to connect multiple processes by pipes? (a | b | c shell pipeline)
• [advanced] Multiple pipes in subprocess (bash process substitution: a <(b) <(c))

Interacting with a subprocess while it is still running

• Read streaming input from subprocess.communicate() (for line in process.stdout)
• Displaying subprocess output to stdout and redirecting it
• A non-blocking read on a subprocess.PIPE in Python
• Run command and get its stdout, stderr separately in near real time like in a terminal (buffering/concurrency: threading, asyncio, pty, select)
• Dialog-based interaction (multiple dynamic requests/responses) (pexpect)
• How to properly interact with a process using subprocess module (explanation for a block-buffering issue)

Windows

• Popen with conflicting executable/path

• Why character '^' is ignored byt Python Popen - how to escape '^' character in Popen Windows?

Misc

• Python subprocess arguments (use shlex.split() to convert a string to a list of arguments)
• Using module 'subprocess' with timeout (timeout=seconds)
• How to get exit code when using Python subprocess communicate method? (.returncode)
• How to hide output of subprocess (stdout=DEVNULL)
• How to terminate a python subprocess launched with shell=True (start_new_session=True + os.killpg)
• Python threading multiple bash subprocesses?
• Python: execute cat subprocess in parallel (ThreadPool or asyncio)

• https://stackoverflow.com/questions/22709646/why-subprocess-call-ignores-asterisk-passing-mv-command (shell=True)
• Why subprocess.Popen doesn't work when args is sequence? (shell=True on POSIX)