I wrote this, hope everyone finds it as interesting reading this as I did figuring this out for the first time!

Isn't there a standard flag which programs can implement to avoid writing this bash script?

Ideally this could all be part of a library such as argparse for typical cases, right?

Do many people do bash on osx or zsh on Linux, and would this make much of a difference?

Shell syntax is the exact reason why we've needed LLMs in the first place.

Why doesn't someone (not me) just build a basic DSL and a transpiler that does this?

I feel that the ergonomics of bash completion took a hit as the configurations got “smarter” and “helpfully” started blocking file or directory name completion if it thinks it wouldn’t be appropriate to have a file name at the current cursor position. Instead of blocking, the default should always be to fall back to filename completion.

Sometimes I’m close to disabling/uninstalling all completion scripts out of irritation as decades of muscle memory are frustrated by this behavior.

It’s like that bad/annoying UX with text fields where the UI is constantly fighting against you in order prevent you from producing “illegal” intermediate input - e.g. let me paste the clipboard here goddammit - I know what I’m doing - I’ll correct it.

Here's zsh snippet I've came up with for my own simple functions. I'm using it as a base for other completions. In this example, function `set-java-home zulu-21` sets JAVA_HOME to `~/apps/java/zulu-21`. Here's `_set-java-home`:

    #compdef set-java-home
    
    local -a versions=(~/apps/java/*(:t))
    _describe 'version' versions

So basically almost a one-liner (but couldn't do it really one-liner, unfortunately).

I wish tcsh would get more love.

I’m not familiar with `_gnu_generic`, but it sounds like a handy shortcut for basic completions without writing a full script. Does it work with commands that only have `--help` but no man pages?

I did something similar to this for tab-completing server names for use with ssh. I went a step further and allowed pattern matching based on the server being qa/prod and on locale. so for instance you could type `ssh co prod <tab>` and it would tab-complete / suggest any servers that were production and located in the Denver datacenter (co is the state abbrev for Colorado, for non-US readers).

Unfortunately my work doesn't allow me to share code, but essentially I remapped ssh to a bash script that maintains an environment variable containing the args (you must do this because each <tab> press is an independent invocation of the script. Then you run into persistence problems, so I added a call to compute elapsed seconds so that it flushes the state variable after a 10s timeout).

The bash script then forwards the args to a python script that reads a JSON file and figures out which params (such as 'co' or 'qa') map to which hostnames. It also matches against partial hostnames, so when you see this after tab

qa-server-co1 qa-server-co2 pr-server-co3

you only need to add '3' to the list of args to narrow it down to 1 match, then hit <enter> to ssh to that host.

Since auto text completion is the primary task of an LLM, I have seen GitHub copilot do that very well on both bash and zsh within vscode terminal!