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Not being a filthy BASH casual?

I use different languages for different purposes. Although bash euns everywhere, its a walking footgun and thus I only use it for small sub 100 line no or one option Scripts. the rest goes to one of Python, which nowadays runs almost everywhere, Julia or a compiled language for the larger stuff

If you just want to move some files around and do basic text substitution, turning to Python or another other "full fledged programming language" is a mistake. There is so much boiler plate involved just to do something simple like rename a file.

You mean

    import os
    os.rename(“src.txt”, “dest.txt”)

?

Yes. And it is only downhill from there.

Now, show us `mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log` in Python.

In ruby you can just call out to the shell with backticks.

Like.

    myvar = `mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log`

That way, if something is easier in Ruby you do it in ruby, if something is easier in shell, you can just pull its output into a variable.. I avoid 99% of shell scripting this way.

That is fair...

But if all I need to do is generate the report I proposed...why would I embed that in a Ruby script (or a Python script, or a Perl script, etc.) when I could just use a bash script?

Bash scripts tend to grow to check on file presence, conditionally run commands based on the results of other commands, or loop through arrays. When it is a nice pipelined command, yes, bash is simpler, but once the script grows to have conditions, loops, and non-string data types, bash drifts into unreadability.

import os

os.system('mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log')

You forgot to point out all those "footguns" you avoided by writing in Python rather than bash...

This has all of the purported problems of doing this directly in a shell language and zero advantages...

That looks like a snippet from a command session which is a perfectly great place to be using sh syntax.

If it became unwieldy you’d turn it into a script:

  #!/bin/sh

  beautify() {
    sed -e ‘
      s/ugly/beautiful/g
      …other stuff
    ‘
  }

  select() {
    awk ‘
      {print $2, $4}
      …other stuff
    ‘
  }

  mycommand | beautify | select

For me, now it’s starting to look like it could be safer to do these things in a real language.

I have a lot of scripts that started as me automating/documenting a manual process I would have executed interactively. The script format is more amenable to putting up guardrails. A few even did get complex enough that I either rewrote them from the ground up or translated them to a different language.

For me, the "line in the sand" is not so much whether something is "safer" in a different language. I often find this to be a bit of a straw-man that stands in for skill issues - though I won't argue that shell does have a deceptively higher barrier to entry. For me, it is whether or not I find myself wanting to write a more robust test suite, since that might be easier to accomplish with Ginkgo or pytest or `#include <yourFavorateTestLibrary.h>`.

Just ask chatgpt and you’ll get a script, probably makes some tests too if you ask for it.

I have not really been a fan of ChatGPT quality. But even if that were not an issue, it is kinda hard to ask ChatGPT to write a script and a test suite for something that falls under export control and/or ITAR, or even just plain old commercial restrictions.

I don’t think it’s fair to compare a workflow that is designed for sed/awk. It’s about 10 lines of python to run my command and capture stdout/stderr - the benefit of which is that I can actually read it. What happens if you want to retry a line if it fails?

> I don’t think it’s fair to compare a workflow that is designed for sed/awk.

If your position is that we should not be writing bash but instead Python, then yes, it is absolutely fair.

> the benefit of which is that I can actually read it.

And you couldn't read the command pipeline I put together?

> What happens if you want to retry a line if it fails?

Put the thing you want to do in a function, execute it on a line, if the sub-shell returns a failure status, execute it again. It isn't like bash does not have if-statements or while-loops.

My point is that if you take a snippet designed to be terse in bash, it’s an unfair advantage to bash. There are dozens of countless examples in python which will show the opposite

> And you couldn't read the command pipeline I put together?

It took me multiple goes, but the equivalent in python I can understand in one go.

> Put the thing you want to do in a function, execute it on a line, if the sub-shell returns a failure status, execute it again. It isn't like bash does not have if-statements or while-loops.

But when you do that, it all of a sudden looks a lot more like the python code

Is it really so bad? A bit more verbose but also more readable, can be plenty short and sweet for me. I probably wouldn't even choose Python here myself and it's the kind of thing shell scripting is tailor-made for, but I'd at least be more comfortable maintaining or extending this version over that:

  from subprocess import Popen, PIPE

  CMD = ("printf", "x:hello:67:ugly!\nyy$:bye:5:ugly.\n")
  OUT = "something.report"
  ERR = "err.log"

  def beautify(str_bytes):
      return str_bytes.decode().replace("ugly", "beautiful")

  def filter(str, \*index):
      parts = str.split(":")
      return " ".join([parts[i-1] for i in index])

  with open(OUT, "w") as out, open(ERR, "w") as err:
      proc = Popen(CMD, stdout=PIPE, stderr=err)
      for line_bytes in proc.stdout:
        out.write(filter(beautify(line_bytes), 2, 4))

I would agree though if this is a one-off need where you have a specific dataset to chop up and aren't concerned with recreating or tweaking the process bash can likely get it done faster.

Edit: this is proving very difficult to format on mobile, sorry if it's not perfect.

Python.

Xonsh. Been using it since 2018. Bash scripting sucks in comparison.

For reference, it seems to be this: https://xon.sh

  XONSH is a Python-powered shell

  Xonsh is a modern, full-featured and cross-platform shell. The language is a
  superset of Python 3.6+ with additional shell primitives that you are used to
  from Bash and IPython. It works on all major systems including Linux, OSX, and
  Windows. Xonsh is meant for the daily use of experts and novices.

Haven't heard of it before personally, and it looks like it might be interesting to try out.

Python or go

I think Python is overused, but this is exactly what Python is great for. Python3 is already installed or trivial to install on almost everything, it has an enormous library of built-ins for nearly everything you'll need to do in a script like this, and for all of its faults it has a syntax that's usually pretty hard to subtly screw up in ways that will only bite you a month or two down the road.

My general rule of thumb is that bash is fine when the equivalent Python would mostly be a whole bunch of `subprocess.run` commands. But as soon as you're trying to do a bunch of logic and you're reaching for functions and conditionals and cases... just break out Python.

I've been pretty happy with the experience of using Python as a replacement for my previous solutions of .PHONY-heavy Makefiles and the occasional 1-line wrapper batch file or shell script. It's a bit more verbose, and I do roll my eyes a bit occasionally at stuff like this:

    call([options.cmake_path,'-G','Visual Studio 16','-A','x64','-S','.','-B',build_folder],check=True)

But in exchange, I never have to think about the quoting! - and, just as you say, any logic is made much more straightforward. I've got better error-checking, and there are some creature comforts for interactive use such as a --help page (thanks, argparse!) and some extra checks for destructive actions.

Zsh

Golang. You build one fat binary per platform and generally don't need to worry about things like dependency bundling or setting up unit tests (for the most part it's done for you).

Babashka/clojure is a fairly pleasant way to write scripts.

I also think bun alongside typescript is quite viable, especially with the shell interop:

https://bun.sh/docs/runtime/shell

Use bash for simple stuff, and Perl or TCL for applications.