Like the way the shell would fork off an "expr" sub-process to parse a mathematical expression to add two numbers, then write the result to a pipe via stdout, then terminate the process, clean up all its resources, and switch context back to the shell, which then read the serialized sum back in from the other end of the pipe, and went about its business, regardless of the fact that the CPU running the shell already had its own built-in "add" instruction in hardware.
Unless you are over fifty years old, you never experienced this.
Rob Pike said it best: "Those days are dead and gone and the eulogy was delivered by Perl."
Perl being a thing in 1995...
[1] https://github.com/baphomet-berlin/jQuery-basic-arithmetic-p...
Shell scripts are guaranteed to be runnable on all machines.
Unfortunately the shell "language" sucks, but still...
Oh, and be very careful of the commands your script invokes!
shell scripts have no guarantee of portability (often less than Python, which has a rich standard library available on all platforms).
Why do you say that? genuinely curious
from subprocess import Popen, PIPE
p1 = Popen(["foo"], stdout=PIPE)
p2 = Popen(["bar"], stdin=p1.stdout, stdout=PIPE)
p1.stdout.close() # Allow p1 to receive a SIGPIPE if p2 exits.
output, _ = p2.communicate()
When you're not writing shell, just use the tools the language gives you.
For the matter, I think a shell script is cleaner than a python script for devops; but I don't think the composability of unix tools is that much of an advantage compared to the amount of python libraries out there.
I'm likely to be using Python programs and other programs in those shell scripts. The beauty of shell is that it makes it so easy to compose programs written in different languages.
I'm curious because these simple things that are delightfully easy in bash often turn out to be surprisingly tedious in other languages.
Of course, some things are tedious in bash too. But a basic principle of shell scripting is that you call other programs to do the stuff you don't want to do in shell.