➜ brew update Error: homebrew-core is a shallow clone. To `brew update`, first run: git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow This command may take a few minutes to run due to the large size of the repository. This restriction has been made on GitHub's request because updating shallow clones is an extremely expensive operation due to the tree layout and traffic of Homebrew/homebrew-core and Homebrew/homebrew-cask. We don't do this for you automatically to avoid repeatedly performing an expensive unshallow operation in CI systems (which should instead be fixed to not use shallow clones). Sorry for the inconvenience!
rm -rf /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core;
ps: rm -rf 有风险，操作需谨慎