Instructions on how to install Fish shell on Mac OS X, including Oh My Fish!. Also includes several useful functions.

fish_shell.md

Installation

1. Install fish via Brew
2. Optionally install Oh My Fish!
3. Add fish to known shells
4. Set default shell to fish

brew install fish  
curl -L https://get.oh-my.fish | fish
sudo bash -c 'echo $(which fish) >> /etc/shells'
chsh -s $(which fish)

Aliases

# shortcuts
alias .. "cd .."
alias cd.. "cd .."
alias ll "ls -la"

# modern tooling (see https://github.com/ibraheemdev/modern-unix)
alias ls exa
alias cat bat

# typos
alias gti git

Functions

Add any the following functions to ~/.config/fish/config.fish

sudo bang bang

Repeat previous command with administrator rights

function sudo
    if test "$argv" = !!
        eval command sudo $history[1]
    else
        command sudo $argv
    end
end

dropbox

Quickly access your DropBox folder

function db
    set user $HOME
    cd "$HOME/Dropbox"
end

icloud drive

Quickly access your iCloud Drive folder

function icd
    set user $HOME
    cd "$HOME/Library/Mobile\ Documents/com\~apple\~CloudDocs"
end

docs

Quickly access your documents folder

function docs    
	switch (uname -s)
    case Darwin Linux FreeBSD NetBSD DragonFly
		set documents $HOME/Documents
	case '*'
		set cygwin (eval uname -o)  
    		if test $cygwin = "Cygwin"
    			set documents (eval cygpath -O)
    		end    
    		return
    	end    
    	cd $documents
    end
end

os

Return platform name

function os
    switch (uname -s)
    case Darwin Linux FreeBSD NetBSD DragonFly
        eval command uname -s
    case "*"`
        switch (uname -s)
        case Cygwin
            eval command uname -s
        case "*"
            eval echo "undefined"
        end
    end
end

git tag

Simplify the creation and deletion of Git tags

function tag
    if count $argv > /dev/null
        if test $argv[1] = "-d"
            # delete tag if provided
            if test $argv[2]
                eval command git tag -d $argv[2]
                command git push origin :refs/tags/$argv[2]
            end
        else
            # create new tag and push
            eval command git tag -a $argv[1] -m $argv[1]
            command git push --tags
        end
    else
    	# list tags
        command git tag
    end
end

nvm

There are plenty of guides on how to get nvm running in Fish. This is the one that works for me.

1. Install bass
2. Add the following to config.fish

# This is what you often find online...
function nvm
    bass source (brew --prefix nvm)/nvm.sh --no-use ';' nvm $argv
end

# ...however, for me it doesn't work without the following line
set -Ux NVM_DIR ~/.nvm

I also had the same issue as @Andrewg1263 and @jadnhm.
It seems as if this gist hasn't been updated to support instructions for ARM architecture.
I forked the gist and revised it to include a quick fix for the issue, if you want to update yours accordingly.

https://gist.github.com/dpeachpeach/07444779df15cadc87ef88d8b381c4c8

I also had the same issue as @Andrewg1263 and @jadnhm. It seems as if this gist hasn't been updated to support instructions for ARM architecture. I forked the gist and revised it to include a quick fix for the issue, if you want to update yours accordingly.

https://gist.github.com/dpeachpeach/07444779df15cadc87ef88d8b381c4c8

This is no longer required. The above instructions have been updated to work on any architecture.