How to Ruby on Apple silicon

.zshenv

# Need to use ~/.zshenv, ~/.zprofile is not sourced when doing "arch -x86_64 /bin/zsh"
#
# From 'man zsh' (zsh 5.8.1 (x86_64-apple-darwin21.0))
#
#       Commands are then read from $ZDOTDIR/.zshenv.  If the shell is a login
#       shell, commands are read from /etc/zprofile and then $ZDOTDIR/.zprofile.
#       Then, if the shell is interactive, commands are read from /etc/zshrc and
#       then $ZDOTDIR/.zshrc.  Finally, if the shell is a login shell,
#       /etc/zlogin and $ZDOTDIR/.zlogin are read.


# Adds the correct Homebrew PATHs to ENV based on arch, example
#
#   $ /opt/homebrew/bin/brew shellenv
#   export HOMEBREW_PREFIX="/opt/homebrew";
#   export HOMEBREW_CELLAR="/opt/homebrew/Cellar";
#   export HOMEBREW_REPOSITORY="/opt/homebrew";
#   export PATH="/opt/homebrew/bin:/opt/homebrew/sbin${PATH+:$PATH}";
#   export MANPATH="/opt/homebrew/share/man${MANPATH+:$MANPATH}:";
#   export INFOPATH="/opt/homebrew/share/info:${INFOPATH:-}";
#
# Inspired by https://tenderlovemaking.com/2022/01/07/homebrew-rosetta-and-ruby.html
if [ $(arch) = "arm64" ]; then
    [ -f /opt/homebrew/bin/brew ] && eval "$(/opt/homebrew/bin/brew shellenv)"
    export RUBIES_DIR="${HOME}/.arm64_rubies"
else
    [ -f /usr/local/bin/brew ] && eval "$(/usr/local/bin/brew shellenv)"
    export RUBIES_DIR="${HOME}/.rubies"
fi

# chruby
chruby_dir="${HOME}/chruby/share/chruby"
if [ -f $chruby_dir/chruby.sh ]; then
    . $chruby_dir/chruby.sh
    . $chruby_dir/auto.sh
fi

# check that the directory exist and have entries except . and ..
[ -d $RUBIES_DIR ] && [ -n "$(ls -A $RUBIES_DIR)" ] && export RUBIES=($RUBIES_DIR/*)

export PATH="$HOME/bin:$PATH"

alias intel='arch -x86_64 /bin/zsh'
alias i='intel'

# pg_ctl needs this to be set
export PGDATA="${HOMEBREW_PREFIX}/var/postgres"

# For pg and sequel_pg gem installs that uses pg_config to find the include dirs
export PATH="${HOMEBREW_PREFIX}/opt/postgresql@14/bin:$PATH"

README.md

How to Ruby on Apple silicon

git clone https://gist.github.com/79aae28811c290b7a6a96ab4fafd4197.git /tmp/arm_mac
mv /tmp/arm_mac/.zshenv ~/
mkdir ~/bin
mv /tmp/arm_mac/rbuild ~/bin
chmod u+x ~/bin/rbuild

cd $HOME
git clone --branch do-no-set-gem-home https://github.com/eregon/chruby.git

source ~/.zshenv

# install ruby for aarch64
brew install ruby-build
rbuild 3.1.2

# install ruby for x86_64
intel
brew install ruby-build
rbuild 3.1.2

rbuild

#!/bin/sh

set -e
set -u

if [ $# -eq 0 ];
then
    echo "Usage: $0 <ruby version>"
    exit 0
fi

command -v ruby-build >/dev/null 2>&1 || echo "No ruby-build, please install it: brew install ruby-build"

RUBY_TO_INSTALL=$1
RUBY_BUILD_PREFIX="${RUBIES_DIR}/${RUBY_TO_INSTALL}"

mkdir -p $RUBIES_DIR

echo "Installing ${RUBY_TO_INSTALL} to ${RUBY_BUILD_PREFIX}"

ruby-build $RUBY_TO_INSTALL $RUBY_BUILD_PREFIX