嘗試：
brew install unrar
報錯，提示：
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/cask).
==> Updated Casks
Updated 1 cask.
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
Error: No available formula or cask with the name "unrar".
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching taps on GitHub...
Error: No formulae found in taps.
解決方法：
brew install carlocab/personal/unrar
感謝這位大兄弟！
參考鏈接：
https://github.com/Homebrew/discussions/discussions/285
https://stackoverflow.com/questions/66042150/mac-os-brew-install-unrar-fails