A follow-up recommendation I give (which I suspect might be unpopular with many around here) is to use Python for all but the most trivial one-liner scripts, instead of shell.

Since 3.5 added `subprocess.run` (https://docs.python.org/3/library/subprocess.html#subprocess...) it's really easy to write CLI-style scripts in Python.

In my experience most engineers don't have deep fluency with Unix tools, so as soon as you start doing things like `if` branches in shell, it gets hard for many to follow.

The equivalent Python for a script is seldom harder to understand, and as soon as you start doing any nontrivial logic it is (in my experience) always easier to understand.

For example:

    subprocess.run("exit 1", shell=True, check=True)
    Traceback (most recent call last):
      ...
    subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 

Combine this with `docopt` and you can very quickly and easily write helptext/arg parsing wrappers for your scripts; e.g.

    """Create a backup from a Google Cloud SQL instance, storing the backup in a 
    Storage bucket.
    
        Usage: db_backup.py INSTANCE
    """
    if __name__ == '__main__':
        args = docopt.docopt(__doc__)
        make_backup(instance=args['INSTANCE'])
 

Which to my eyes is much easier to grok than the equivalent bash for providing help text and requiring args.

There's an argument to be made that "shell is more universal", but my claim here is that this is actually false, and simple Python is going to be more widely-understood and less error-prone these days.