This may make some people pull their hair out, but I’d love to hear some arguments. I’ve had the impression that people really don’t like bash, not from here, but just from people I’ve worked with.
There was a task at work where we wanted something that’ll run on a regular basis, and doesn’t do anything complex aside from reading from the database and sending the output to some web API. Pretty common these days.
I can’t think of a simpler scripting language to use than bash. Here are my reasons:
- Reading from the environment is easy, and so is falling back to some value; just do
${VAR:-fallback}; no need to write another if-statement to check for nullity. Wanna check if a variable’s set to something expected?if [[ <test goes here> ]]; then <handle>; fi - Reading from arguments is also straightforward; instead of a
import os; os.args[1]in Python, you just do$1. - Sending a file via HTTP as part of an
application/x-www-form-urlencodedrequest is super easy withcurl. In most programming languages, you’d have to manually open the file, read them into bytes, before putting it into your request for the http library that you need to import.curlalready does all that. - Need to read from a
curlresponse and it’s JSON? Reach forjq. - Instead of having to set up a connection object/instance to your database, give
sqlite,psql,duckdbor whichever cli db client a connection string with your query and be on your way. - Shipping is… fairly easy? Especially if docker is common in your infrastructure. Pull
Ubuntuordebianoralpine, install your dependencies through the package manager, and you’re good to go. If you stay within Linux and don’t have to deal with differences in bash and core utilities between different OSes (looking at you macOS), and assuming you tried to not to do anything too crazy and bring in necessary dependencies in the form of calling them, it should be fairly portable.
Sure, there can be security vulnerability concerns, but you’d still have to deal with the same problems with your Pythons your Rubies etc.
For most bash gotchas, shellcheck does a great job at warning you about them, and telling how to address those gotchas.
There are probably a bunch of other considerations but I can’t think of them off the top of my head, but I’ve addressed a bunch before.
So what’s the dealeo? What am I missing that may not actually be addressable?
May I introduce you to rust script? Basically a wrapper to run rust scripts right from the command line. They can access the rust stdlib, crates, and so on, plus do error handling and much more.
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Yeah, sometimes I'll use that just to have the sane control flow of Rust, while still performing most tasks via commands.
You can throw down a function like this to reduce the boilerplate for calling commands:
Then you can just write
run("echo 'hello world' > test.txt");to run your command.Defining
runis definitely the quick way to do it 👍 I'd love to have a proc macro that takes a bash like syntax e.gsomeCommand | readsStdin | processesStdIn > someFileand builds the necessary rust to use. xonsh does it using a superset of python, but I never really got into it.Anti Commercial-AI license
I believe, cmd_lib is the most widely used library that does this.
duct is also popular, but uses a somewhat more conservative syntax.
Wow, that's exactly what I was looking for! Thanks dude.
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Isn't that just Python? :v
How easily can you start parsing arguments and read env vars? Do people import clap and such to provide support for those sorts of needs?
I'd use clap, yeah. And env vars
std::env::var("MY_VAR")?You can of course start writing your own macro crate. I wouldn't be surprised if someone already did write a proc macro crate that introduces its own syntax to make calling subprocesses easier. The shell is.. your oyster 😜Anti Commercial-AI license
I can only imagine that macro crate being a nightmare to read and maintain given how macros are still insanely hard to debug last I heard (might be a few years ago now).
Check out @Ephera@lemmy.ml's comment with existing libraries. Someone already did the work! 🎉
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I’m so glad we have madlads in rust land xD Thanks for referring me to that!
proc macros can be called in tests and debugged. They aren't that horrible, but can be tedious to work with. A good IDE makes it a lot easier though, that's for sure.
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