Separating Homebrew settings for M1 and Intel processors

The Issue

I bought a Mac equipped with an M1 processor, but since I also work on a Mac with an Intel processor, the settings shared between both resulted in errors.

Solution

I addressed this by branching the configuration based on the differences in CPU architecture.

Homebrew

The following example is a configuration file for fish, but you should be able to adapt it for other shells as well.

$HOME/.config/fish/config.fish

switch (uname -m)
case x86_64
  set HOMEBREW_DIR /usr/local
case arm64
  set HOMEBREW_DIR /opt/homebrew
end

# Homebrew
set -U fish_user_paths "$HOMEBREW_DIR/bin" $fish_user_paths

asdf

Also, since I use asdf to manage language runtime versions, I configured that in a similar way.

$HOME/.config/fish/config.fish

# asdf
source "$HOMEBREW_DIR/opt/asdf/asdf.fish"