Welcome to the lab.

In my last post on the Fish shell, I brazenly stated that “because of the way that Fish handles the prompt function, there’s no easy way to hook it without modifying the original theme files.” That was 100% incorrect, as I figured out the next day.

Fish has the ability to specify that any function act as an event handler. You can attach to the event fish_prompt to have the function run right before the prompt displays. So my revised function in my init file is:

function __should_na --on-event fish_prompt
  set -l cmd (history --max=1|awk '{print $1;}')
  set -l cds cd z j popd g
  if contains $cmd $cds
    test -s (basename $PWD)".taskpaper" && ~/scripts/fish/na
  end
end

Now I no longer need to edit the theme files directly at all, which is much more how I’d prefer things to be. As an alternative to fish_prompt, you can also attach to variables changing, which means you can use PWD to run the function any time the working directory changes. That would look like:

function __should_na --on-variable PWD
	...

Also, any function can use the emit command to add its own hook. The example from the docs is nice and succinct:

function event_test --on-event test_event
    echo event test: $argv
end

emit test_event something

This is one area where the Fish documentation seems lacking: there’s no list of available hooks nor (that I can find) any way to retrieve a list of emitted events in the shell. It’s been trial and error for me thus far. Hopefully someone will correct me if I’m wrong here. Update, someone (evanrelf) did correct me in the comments: you can find a list of all named events using function -h.

Ok, so that’s an extended correction to my last post, but it’s a cool enough aspect of Fish that it seemed worth covering on its own.

Given that Apple has already switched the default shell in Catalina from Bash to Zsh, I’ve been thinking I really need to expand from Bash. Don’t get me wrong, I love Bash and I’ve spent years molding it to my liking. The amount of time I’ve put into it and the ease with which that investment allows me to use it has always made switching to anything else seem, well, like a waste of time. But now I feel stuck. To that end, I’ve been stretching out and trying to shake off my fear of getting to know other shells.

I decided to spend some time getting comfortable with Zsh and Fish (the Friendly Interactive SHell). I started with Fish, building a configuration on weekends. Three weekends now and I’m comfortable enough to use it as my regular shell during the week.

Fish features advanced autosuggestion and expansions, does cool syntax highlighting, offers a “sane” scripting toolset, has an array of existing plugins and themes, and even sports a browser-based configuration tool that’s pretty awesome. So here are some random notes from my travels. This is a journal, not a tutorial, containing my impressions and a few tips.

First off, I promise an nvUltra update this week. You deserve it. In the meantime…

I woke up at three this morning. As you may have come to expect, I’ve added stuff to Bunch, my batch app launcher and current too-awake-to-sleep-too-tired-to-do-real-work project. I think this new feature will save a few users (and myself) some time: I’m calling it “snippets,” which is an uncreative way of saying you can now use templated actions with variables in a Bunch.