Needs a (1990) tag. It always amuses me when people, to this day, say "eh, not going to use that newfangled zsh, bash was good enough for my forefathers and is good enough for me" - not realizing zsh was released less than a year after bash.
My main pain point was that zsh was really difficult to configure out of the box and a lot of the completions were much slower (cpu/wall time) than the equivalent completion in bash.
I'm sure some of that was simply ignorance on my part.
I guess that bash being the default practically everywhere nowadays made it so that it got a lot of love. For example, it is common to see command line tool come with bash completion files, less so with zsh.
Also, while bash got better support where it matters, zsh mostly got bloat in the form of oh-my-zsh and the likes. You don't have to use it, but if you do, you tend to have all kinds of fancy stuff that affects performance. Also, if you want something fancy, you have fish now.
I still use zsh (without oh-my-zsh) out of habit, but if I had to start over now, I would probably stay with bash, or maybe use fish, but not zsh.
> For example, it is common to see command line tool come with bash completion files, less so with zsh.
It's rare for bash to complete anything but filenames. zsh gives me subcommands and flags with descriptions.
> Also, while bash got better support where it matters, zsh mostly got bloat in the form of oh-my-zsh and the likes.
zsh is a well-maintained project. It makes no sense to ignore that and instead fault them for oh-my-zsh's shortcomings, as if it has anything to do with upstream zsh. zsh doesn't rely on oh-my-zsh for any of its features.
I think that hasn't been true for a very long time, although it might be that I'm biased because I've been installing the "bash completion" package alongside bash on all my systems. (In my case "apt-get install bash-completion".)
bash typically completes commands, sub-commands, flags, and file/directory names for me. It is also common for new tools to ship with bash-completion support, often missing support for other shells.
Take grep, for example. I only get --binary-files, --context, and --null. That's only three out of a few dozen options. Or tar, which only shows c, t, and x. For ls, probably the most frequently used command, only --color and --help. Git requires another third party completion framework. Unfortunately, those are the best case examples. For other commands like vim or emacs, option completion is missing. The same even goes for bash builtins. And don't get me started on completion behavior. Though I will say the lack of descriptions for each option takes away half the usefulness of shell completion.
zsh can actually use completion functions written for bash. But I never felt the need.
I'd probably suggest that bash-completion being a "third party" package is a good thing, it's entirely external to the bash project and that's good. It means we're not pinned to releases alongside the shell. After all it has support for ssh, grep, and many more tools they should be able to contribute to one location and the shell-project itself would be thee wrong one.
bash completion provides a framework for adding completion to "stuff", and the git-package on Debian uses that to drop a file into `/usr/share/bash-completion/completions/` so there's no need for any other third party framework:
1. Install git 2. Install bash completion package 3. Everything should just work.
Anyway I guess a lot of this will depend on the system you're using, and how their packages are configured, but I don't personally believe that bash completion is in a terrible state.
Then again, I don't do much with the shell per se (not writing scripts or any thing like that).
Easier to change my other systems to zsh than fight it, but I've not really done anything different except some minor notices that it seems to autocomplete a tiny bit better (but that may be due to oh my zsh).
In any case, fish offers all the conveniences out-of-the-box, which makes it superior to zsh, to me. It's just a nice and ready drop-in, no configuration required. Like, I can't live without alt-H to pop open the man page for command at cursor, and alt-S to toggle sudo, anymore. Otherwise, for 95% of my use, the differences are unnoticeable, and if I need the arcane bash hacks, well, I drop into a bash shell. Tho, I do miss the <<< and still use bash for scripts. Also, I don't have fish set as default shell outside of the GUI terminal.