M1 dual homebrew (x86_64 and arm64) setup

.zshrc

#
# .zshrc for Mac M1 chips to handle both x86_64 and arm64 homebrew
#
# Be sure to remove .zprofile in order to prevent invalid paths, and
# remove /usr/local/bin from /etc/paths.
#
# Install both arch homebrew versions with:
# arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
# arch -arm64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

alias ishell="arch -x86_64 /bin/zsh"
alias ashell="arch -arm64 /bin/zsh"

arch_name="$(uname -m)"

# Reset the paths
if [ -x /usr/libexec/path_helper ]; then
    unset PATH
    eval `/usr/libexec/path_helper -s`
fi
 
if [ "${arch_name}" = "x86_64" ]; then
    eval "$(/usr/local/bin/brew shellenv)"
    if [ "$(sysctl -in sysctl.proc_translated)" = "1" ]; then
        echo "Running on Rosetta 2"
    else
        echo "Running on native Intel"
    fi 
elif [ "${arch_name}" = "arm64" ]; then
    eval "$(/opt/homebrew/bin/brew shellenv)"
    echo "Running on ARM"
else
    echo "Unknown architecture: ${arch_name}"
fi