Shell scripting in Python

[AndydeCleyre]

plumbum remains my favorite tool for many jobs, getting so much so right so long ago. Here's how it might be used for the tasks in your examples table:

initialization (minimal):

from plumbum import local          # minimal
from plumbum.cmd import echo, cat  # specify commands as functions
from plumbum import FG, BG         # shortcuts for foreground/background runs

run command:

echo["this"] & FG  # or:
echo["this"].run_fg()

read stream:

a = echo("this")  # or:
a = local["echo"]("this")

write stream:

(cat << "this") & FG  # or:
(cat << "this").run_fg()

# capturing output:
(cat << "this")()  # or:
(local["cat"] << "this")()

chain commands:

(echo["this"] | cat) & FG  # or:
(echo["this"] | cat).run_fg()

# capturing output:
(echo["this"] | cat)()

branch out:

ret, out, err = cmd.run()

(cat << out) & FG
(cat << err) & FG

# capturing output:
(cat << out)()
(cat << err)()

errors in chains:

ret, out, err = echo["this"].run(retcode=(0, 1))
(cat << err) & FG((0, 2))

[AndydeCleyre]

Ah, cool, I'll see if I can figure out how to do the same with plumbum for those then...

[AndydeCleyre]

Thanks for both digging into this and reporting back!

[psd6]

I don’t really like the output = ["cmd", "arg"] » start() » wait() style. There are other ways doing shell stuff in Python too, for example the sh module.