One day, someone’s going to have to debug machine-generated Bash. <shivver>

Looking at the example

Why does the generated bash look like that? Is this more safe somehow than a more straighforward bash if or does it just generate needlessly complicated bash?

The language idea is good, but: THREE.WebGLRenderer: A WebGL context could not be created. Reason: WebGL is currently disabled.

Seriously? Why do I need WebGL to read TEXT in docs? :/

As someone who has done way too much shell scripting, the example on their website just looks bad if i’m being honest.

I wrote a simple test script that compares the example output from this script to how i would write the same if statement but with pure bash.

here’s the script:

#!/bin/bash

age=3

[ "$(printf "%s < 18\n" "$age" | bc -l | sed '/\./ s/\.\{0,1\} 0\{1,\}$//')" != 0  ] && echo hi

# (( "$age" < 18 )) && echo hi

Comment out the line you dont want to test then run hyperfine ./script

I found that using the amber version takes ~2ms per run while my version takes 800microseconds, meaning the amber version is about twice as slow.

The reason the amber version is so slow is because: a) it uses 4 subshells, (3 for the pipes, and 1 for the $() syntax) b) it uses external programs (bc, sed) as opposed to using builtins (such as the (( )), [[ ]], or [ ] builtins)

I decided to download amber and try out some programs myself.

I wrote this simple amber program

let x = [1, 2, 3, 4]
echo x[0]

it compiled to:

__AMBER_ARRAY_0=(1 2 3 4);
__0_x=("${__AMBER_ARRAY_0[@]}");
echo "${__0_x[0]}"

and i actually facepalmed because instead of directly accessing the first item, it first creates a new array then accesses the first item in that array, maybe there’s a reason for this, but i don’t know what that reason would be.

I decided to modify this script a little into:

__AMBER_ARRAY_0=($(seq 1 1000));
__0_x=("${__AMBER_ARRAY_0[@]}");
echo "${__0_x[0]}"

so now we have 1000 items in our array, I bench marked this, and a version where it doesn’t create a new array. not creating a new array is 600ms faster (1.7ms for the amber version, 1.1ms for my version).

I wrote another simple amber program that sums the items in a list

let items = [1, 2, 3, 10]
let x = 0
loop i in items {
    x += i
}

echo x

which compiles to

__AMBER_ARRAY_0=(1 2 3 10);
__0_items=("${__AMBER_ARRAY_0[@]}");
__1_x=0;
for i in "${__0_items[@]}"
do
    __1_x=$(echo ${__1_x} '+' ${i} | bc -l | sed '/\./ s/\.\{0,1\}0\{1,\}$//')
done;
echo ${__1_x}

This compiled version takes about 5.7ms to run, so i wrote my version

arr=(1 2 3 10)
x=0
for i in "${arr[@]}"; do
    x=$((x+${arr[i]}))
done
printf "%s\n" "$x"

This version takes about 900 microseconds to run, making the amber version about 5.7x slower.

Amber does support 1 thing that bash doesn’t though (which is probably the cause for making all these slow versions of stuff), it supports float arithmetic, which is pretty cool. However if I’m being honest I rarely use float arithmetic in bash, and when i do i just call out to bc which is good enough. (and which is what amber does, but also for integers)

I dont get the point of this language, in my opinion there are only a couple of reasons that bash should be chosen for something a) if you’re just gonna hack some short script together quickly. or b) something that uses lots of external programs, such as a build or install script.

for the latter case, amber might be useful, but it will make your install/build script hard to read and slower.

Lastly, I don’t think amber will make anything easier until they have a standard library of functions.

The power of bash comes from the fact that it’s easy to pipe text from one text manipulation tool to another, the difficulty comes from learning how each of those individual tools works, and how to chain them together effectively. Until amber has a good standard library, with good data/text manipulation tools, amber doesn’t solve that.

Compiling to bash seems awesome, but on the other hand I don’t think anyone other than the person who wrote it in amber will run a bash file that looks like machine-generated gibberish on their machine.

There’s a joke here but I’m not clever enough to make it.

I’m very suspicious of the uses cases for this. If the compiled bash code is unreadable then what’s the point of compiling to bash instead of machine code like normal? It might be nice if you’re using it as your daily shell but if someone sent me “compiled” bash code I wouldn’t touch it. My general philosophy is if your bash script gets too long, move it to python.

The only example I can think of is for generating massive install.sh

I like the idea in principle. For it to be worth using though, it needs to output readable Bash.

Just learn Bash lol

Why not compile it to sh though.

let

with no support for associative arrays (dicts / hashmaps) or custom data structs this looks very limited to me

I’m a mathematician with very limited programming experience. Can someone explain the significance of this?

As a long-time bash, awk and sed scripter who knows he’ll probably get downvoted into oblivion for this my recommendation: learn PowerShell

It’s open-source and completely cross-platform - I use it on Macs, Linux and Windows machines - and you don’t know what you’re missing until you try a fully objected-oriented scripting language and shell. No more parsing text, built-in support for scalars, arrays, hash maps/associative arrays, and more complex types like version numbers, IP addresses, synchronized dictionaries and basically anything available in .Net. Read and write csv, json and xml natively and simply. Built-in support for regular expressions throughout, web service calls, remote script execution, and parallel and asynchronous jobs and lots and lots of libraries for all kinds of things.

Seriously, I know its popular and often-deserved to hate on Microsoft but PowerShell is a kick-ass, cross-platform, open-source, modern shell done right, even if it does have a dumb name imo. Once you start learning it you won’t want to go back to any other.

Here’s a language that does bash and Windows batch files: https://github.com/batsh-dev-team/Batsh

I haven’t used either tool, so I can’t recommend one over the other.