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 

    """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'])
 

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.

As someone who hasn't used Python in ages, and finds it quite unreadable, I would be saddened and dismayed if instead of shell (which is the lingua franca) a project used Python everywhere.

The exception being if it's a Python app in the first place, then it's fine since it can be assumed you need to be familiar with Python to hack on it anyway. For example I write a lot of Ruby scripts to include with Sinatra and Rails apps.

For a general purpose approach however, everybody should learn basic shell. It's not that hard and it is universal.

Ever tried to parse XML or json in linux shell?

It's not a matter of familiarity with linux shell. It's a matter of wasting time debugging/implementing stuff in shell that is trivial to implement in any modern scripting language.