I have a simple Python script which live-prints the output of a command. Following is the script:
#!/usr/bin/env python3 import subprocess def RunSubProcess(process, process_args): process = subprocess.Popen([process, process_args], stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True) while process.stdout.readable(): line = process.stdout.readline() if not line: break print(line.strip()) RunSubProcess('ls', '-la')
The script works well for what it should do but it loses color coding of the output on my shell. If I type ls -la
, I get the output well-colored. But if I run the above Python script, it gives the output uncolored.
Is there an argument to subprocess.Popen
that could preserve color coding of the shell it’s running on?
PS:
I am running this Python script on a bash shell on MacOS with Python 3.9.0 installed.
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Answer
Many programs detect whether they are connecterd to a terminal, and switch to different behaviors for interactive use.
Some provide options to force interactive features (try ls --color=always
but what exactly works depends on your platform; this is not standardized behavior. The macOS ls
man page says to set CLICOLOR=yes
in the environment) and others can be fooled into believing they are running interactively by using the pty
library, or pexpect
which is a higher-level package and somewhat easier to work with.