alt Hacker NewsArticles like this are fun but they all come from posix shell syntax being fundamentally bad for scripting/programming. All the piping stuff is great, of course. And the overall ecosystem is great. But the interpretation of the script itself working by a series of string substitutions is a mechanism we wouldn't accept in a regular programming language. And there's no excuse for it really, except that shell syntax is really, really old.
For example, what does `$foo` mean in shell syntax? In any reasonable language (perl or powershell, for example, or python if you drop the `$`), it's an expression that evaluates to whatever value's inside that variable. In shell, `$foo` isn't an expression in that sense, and what it does depends on what's inside it via a variety of string substitution rules.
This is the main reason we have arcane articles like this.
That said, nice article.
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Your `$foo` example confused me at first because I thought the backticks are part of the example.
> fundamentally bad for scripting/programming […] a mechanism we wouldn’t accept in a regular programming language
I don’t agree with this assumption that shell should use mechanisms we accept in “regular” programming languages, whatever that means. And why not the other way around? Why do we accept mechanisms in programming that we wouldn’t accept in a shell? There are layers of assumption in your assumption.
I also disagree with lumping scripting and programming together. Those are two different activities, and shell is better at scripting than programming, and it’s better at scripting than programming languages.
Try using python as your shell, and you’ll find out that python is fundamentally bad as a shell REPL. The shell is necessarily different from python or C++ or <your_favorite_programming_language>, starting with the ability to run command lines by typing them, with zero extra syntax. That is something regular programming languages can’t do, and it leads directly to the need for string substitution rules.
If you want a shell made out of a good programming language… make one! People have been thinking about this for decades and nobody has come up with a good one, because shell languages like bash are better at shelling than programming languages.
I will immediately remove all the shell scripts on my system based on this comment alone.
Posted from my phone since my system came crashing down.
Yes a large percentage of bash scripts fails if you feed them filenames with spaces or other special characters. Or a large amount of filenames near the Unix maximum commandline length.
Bash et al are great for command line use, but produce a situation of really bad engineering hygiene when used in scripts.
Do not use. Stay away. Bash et al considered harmful. Red flags on job interview when referenced.
I feel the need to push back on this perspective.
Old doesn't imply arcane. It instead can (and does, in this case) mean that it won out over the course of decades against other less worthy alternatives.
Although you can write "programs" in sh, the shell syntax was never meant to be anything like a systems or application programming language. It was meant to efficiently automate systems tasks. It is kind of like the fork lift of computing. It does it's job very well, is bad at doing anything else, yet no other kind of vehicle can do it's job nearly as efficiently.
Comparing the shell to C, Go, Rust, Python, or JavaScript is crazypants. It has a different job than those, so of course it will look and feel different!