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.

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.

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.

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.

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

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.

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...