Scripting

Misc scripting things

Hush Lang

New scripting language: https://hush-shell.github.io/

Written in Rust
Strongly Typed, Garbage collected, 1st class shell capabilities
Syntax a mix of Go, Rust, and Typescript; “Inspired by Lua”
Provides standard library std with common functions and constants
Proper if, for, and while. Built in list and dict types.
dict can have function values for keys (aka “a method” sort of)
syntax errors panic and app errors return std.error("...")
- adding a ? to something which may return an error panics if an error is returned.
execute commands in “command blocks”: { touch /etc/config }
- can return a proper “std.error” type or a result
- multiple commands per block delimited by ;
- supports pipelines and redirection using standard syntax
- variables defined outside can be used using $var / ${var} / etc.
- error in any command stops unless followed by a ? (opposite behavior to in normal lang)
supports launching command blocks async using let handle = &{...} and handle.join() to wait for completion

function run()
    { mkdir /etc/config/ }?
    std.print("Success!") # This won't be executed if the command block fails.
end

let result = run()
if std.type(result) == "error" then
    std.print("Error: ", result)
end

Bash one-line script; Print “sleep” every 10 seconds forever

$ bash -c while true; do echo sleep; sleep 10;done && echo done

Needed this once because I needed to run a custom command in a Fargate task with two “essential” containers. One of those containers would exit immediately which would interrupt the other command which was migrating the database so I wrote this up to have it “do nothing” without spending too much CPU.