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by atomicnumber3 1147 days ago
Shell is full of ridiculous footguns though. It's like saying if the store is only 60m away (across an Indiana Jones-tier trap gauntlet) then just walk there.

Remember that time bumblebee accidentally deleted everyone's /usr? Or that time steam deleted everyone's homedir? Both because of the easiest to avoid bash footguns - spaces and empty variables.

My hard and fast rule that I've never regretted is - if you use a bash if statement, consider python. If you're going to do a for loop, you must instead use python.

Typically as a side effect once the programmer is in python at my prompting, they find having such easy access to libraries suddenly lets them make the whole script more robust - proper argparsing is an immediate one that comes to mind.

Frequently the reticence I see from people, especially juniors, is that they're worried about people thinking "haha they have to pull an entire python into their image just to run this script" or "wow they're so newbie/young that they can't even write some shell". I reassure them: don't worry, there's a reason we used Perl even back then too.

3 comments

The shell is not meant to implement the X Window System in it. The shell is a command interpreter.

If you want to do more advanced things there is always the right tool for the job although with an increased attack surface.

Have you not used Python or Perl much? Because both are full of footguns. And I don't see any advantage to for loops in a HLL. These are identical:

  for i in `seq 1 10` ; do
    echo i $i
  done

  for i in range(1,10):
    print("i %i\n")
You might find problems with the shell code, and I'll find problems with the Python. But both will print 1 to 10.
Personally I've found Python to have significantly fewer foot-guns than bash.

The biggest reason why I don't use it all of the time is that calling / piping commands takes a lot more typing, so it's easier to use bash for very simple shell scripts. And while there are libraries that simplify shell scripting, that adds external dependencies to your scripts.

> for i in range(1,10): > print("i %i\n")

This outputs "i %i\n\n" 9 times.

> This outputs "i %i\n\n" 9 times.

damn, ya got me there. to be fair, I was drunk when I wrote that xD

Come on, they aren't full of footguns in basic things like string comparison or variable assignment.

Most of the things on this list couldn't happen in Python:

https://mywiki.wooledge.org/BashPitfalls

> Remember that time bumblebee accidentally deleted everyone's /usr? Or that time steam deleted everyone's homedir? Both because of the easiest to avoid bash footguns - spaces and empty variables.

https://www-uxsup.csx.cam.ac.uk/misc/horror.txt

Your exanples were bugs which were not caught during development because "testing is hard and expensive" and "if it compiles, ship it".

And yet Rust gains traction over C. "Best practice" can't fix a dangerous tool.