This guide assumes you have migrated to at new M1(Or other Silicon) based mac via timemachine, mac-to-mac or similar.
Running brew update then gives the following messeage:
Error: Cannot install in Homebrew on ARM processor in Intel default prefix (/usr/local)!
Please create a new installation in /opt/homebrew using one of the
"Alternative Installs" from:
https://docs.brew.sh/Installation
You can migrate your previously installed formula list with:
brew bundle dump
Running brew bundle dump as suggested creates a file in your current folder named Brewfile
Migration process
1. Uninstall old brew and packages
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/uninstall.sh)"
2. Install brew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
3. Import from Brewfile
Run the following command from the same folder as you ran brew bundle dump
brew bundle --file Brewfile
This transfers all previous installed app.