Allow Variable To Be Set To stderr Value For a Command

[MartinPacker]

Today you can set a variable to the stdout from a command but you can't set a variable to the stderr of a command. It would be nice if you could. Suggested syntax:

=def var1,var2 commandstring

where the command string is surrounded by backticks.

var1 would continue to be stdout. var2 would be stderr.

[MartinPacker]

Working in local code but subprocess module doesn't seem to allow separate retrieval of stdout and stderr.

[MartinPacker]

This demo code seems to do what I want:

import subprocess

cp = subprocess.run('ls -l | grep "pptx"', capture_output = True, shell = True)
print(cp.stdout)
print("---")
print(cp.stderr)
print("===")

It

1. Shows piping (already in mdpre)
2. Shows command line arguments (already in mdpre)
3. Shows stderr and stdout as separate things (the new bit)

[MartinPacker]

Coded and tested in mdpre. Documentation needed.

[MartinPacker]

Shipped in v0.8.1.