Homebrew
Homebrew is a free and open-source software package management system that simplifies the installation of software on Apple's operating system, macOS.
Update & Upgrade
Update
First, you need to fetch the newest version of Homebrew and all formulae from GitHub using git and perform any necessary migrations.
brew update
Upgrade
To upgrade all the outdated casks and outdated, unpinned formulae using the same options they were originally installed with.
brew upgrade
To upgrade a particular cask or formulae:
brew upgrade [installed_formula / installed_cask]