6/18/2026 at 5:31:03 AM
I have a complex fish shell configuration with ~100 autoloaded functions and about 180 lines across config.fish and a dozen conf.d/ files.On my system, hyperfine says fish loads in about 85ms:
Benchmark 1: fish -il -c exit
Time (mean ± σ): 85.0 ms ± 3.3 ms [User: 50.1 ms, System: 31.4 ms]
Range (min … max): 82.9 ms … 101.1 ms 28 runs
by kstrauser
6/18/2026 at 6:24:03 AM
On my 6-year old PC, an interactive zsh starts more than 4 times faster, but this is a rather minor detail.Which are in your opinion the advantages of fish over zsh?
The fish tutorial from its Web site highlights some very important advantages of fish over bash/ksh/sh, but all of them are taken from zsh, which had them long before the creation of fish (e.g. features that eliminate the need for the excessive quotation that is necessary in bash/ksh/sh).
Fish has various syntactic differences in comparison with zsh, in some places fish is more concise, but in others it is more verbose, and it is more verbose in things that are more frequently used (e.g. "set" vs. "=", "and" vs. "&&" etc.), while being more concise in things that are more rarely used.
Therefore, from the fish tutorial I see why it is preferable to bash/ksh/sh, but I see no reason to prefer it to zsh.
by adrian_b
6/18/2026 at 6:38:39 AM
This is my go-to example:Say you want to make an autoloaded function in zsh. Go ahead and look that up. Unless you're one of the zsh maintainers, you probably don't have that syntax memorized. I don't mean that personally. The whole time I used zsh, I certainly didn't remember it and had to look it up each time.
In fish, you define a function named "foo" in a file in a specific directory: ~/.config/fish/functions/foo.fish. That's the entire process. When you type "foo" at the command line, and fish can't find that command anywhere, it'll look in that directory for foo.fish, and if it finds it, it'll load that file and execute the "foo" function defined inside it.
Now, say you want to customize your zsh prompt and have it show you the output of a couple of commands, maybe with some colors. It's a fun exercise to try to get something working purely from memory, but that's a test I never managed to pass.
Want to do it in fish? Follow that pattern above to define an autoloaded function called "fish_prompt". Put it in ~/.config/fish/functions/fish_prompt.fish. It's just a normal function where you can use "echo" and "git" and any other command on your system to write the components of your prompt to stdout. That's it. You're done. There's no step 2. Any other time I want to draw something on the screen, I'd use a series of shell commands to write it out to the screen, so why shouldn't it work exactly the same way for my shell prompt? Well, with fish, it does.
That expirement ruined bash and zsh for me. I don't spend a lot of time continually customizing my shell prompt, but the once every couple of years I want to, it's a huge relief to know I just have to edit that function to write out my new idea and that's the end of it. There's just so much less magic to learn and remember with fish that I don't want to go back.
And to be clear, I know my way around several other shells. I love fish because I've used the others enough to become very competent with them, not because I don't know the others or they're too hard for me or anything like that. By programming language analogy, I'm capable of writing decently sized programs in a few flavors of assembler. But man, life's too short to use it for everything, unless that's just the kind of hair shirt you're into wearing.
by kstrauser
6/18/2026 at 6:55:55 AM
Thanks.I use a rather complicated zsh prompt, complicated enough so that I could never convince bash to execute an equivalent prompt correctly, despite the fact that the features used by the prompt are supposed to be supported in bash too.
(The prompt syntax is quite different in zsh and in bash. This is the zsh syntax of my prompt:
PS1=%F{cyan}"[%T %n@%m:%~]"$'\n'%#%fAs you say, to be able to write the prompt I had to study carefully the zsh manual.
However, I consider this a minor disadvantage, because I have written the prompt many years ago, when I have switched from bash to zsh, and I have never had any reason to change it.
I agree that for rarely used features it is more likely to be necessary to search the manual for zsh than for fish, but for me this happens seldom enough to not consider it a decisive disadvantage.
by adrian_b
6/18/2026 at 7:19:33 AM
I do get that, and thought that way too at first. In my case, I found that it being so trivially easy to do these 2 things made them things I did more often. Go ahead and make a thousand convenience scripts and aliases for whatever mischief you want to get up to. There’s no measurable effect on startup time between have 1 autoload function and 1,000. Because it’s free, and so dead simple to do, I never avoid it anymore. There’s no worrying of my startup script’s getting too long and slowing things down, so there’s no downside to doing the things that make my life easier.For me, it unlocked a completely different mindset. Fish isn’t for everyone, any more than chocolate or steak are, and that’s cool. I’m glad we have options.
by kstrauser
6/18/2026 at 6:07:02 AM
That's a ridiculously low number. Wow! I don't think my personal mac has such speed either. I should definitely try this out.by thallavajhula