Out of curiosity, what features were you missing in fish? I've been using it for a while and haven't noticed anything, but I am probably not in need of heavy on shell scripting.
I've heard of plenty of people choosing zsh instead of fish, but I started on fish and never felt the need to switch, so I'm kind of wondering what I might be missing out on.
Substitution via `=()`, `<()`, and `>()`. `=()` save's a process output in a temporary file that I don't have to mess with explicitly and substitutes itself with the path. An example of use is `viewnior =(maim -s)` which shows in an image viewer a window that I select; `diff -u <(...) <(...)` or `cmp`, or `comm` instead of `diff` compares the output of multiple processes without having to save them to files; `tee >(...) >(...) | ...` feeds the output of one command to multiple commands without needing to save files
Subshells. I've used them interactively, and I prefer to not have troubles with quoting doing `fish -c '...'` in my commands.
Extended globbing. It's far more concise and less error prone than using a combination of `find` and text processing tools.
Dynamic directories. ~some_project/ for me expands to ~/work-for/client/some_client/some_project/ and works great with completion.
What attracted me the most to fish was the ability to work with multi-line commands as a single command in the history. However, I've seen that zsh has better support for this.
What killed fish for me back then was that their pipes were fake back then. This is something that they've since fixed, but back then, instead of running all commands at the same time with their inputs and outputs linked, I think fish would run the first command, save it to a file and then ran the second command with that file as input. I mean, the behaviour that I saw was that I wouldn't see any output until the first command finished, and some of the commands that I wanted to run took very long to finish or never were supposed to finish without me seeing some of the output first. I'm talking about watching file changes under a directory and manipulating the presentation of the output of the file watching command (e.g. `inotifywait -m ... | awk ...`) or looking for specific events in the system log as they happened (e.g. `journalctl -f | grep ...`) or looking for specific system calls of a never-ending running process (e.g. `strace -fe trace=file -p $pid | grep ...`). That made fish pipelines useless for me.
Anyway I wrote a more lengthy post once describing the differences between bash and zsh that I liked:
However, there must be more differences between fish and zsh. I can think of history syntax, right now. I can get an argument from any command I've ever typed based on a substring by doing !?substring?%. If I find myself calling two commands in succession multiple times, I can combine them in a single command without retyping them by doing `!-2; !!`. Then I only have 1 command to re-run next time instead of 2. If I typed a command and realize I want to include the last argument of the previous command, I can type `!$` to include it.
