mac$ brew install node
==> Downloading https://homebrew.bintray.com/bottles/node-11.6.0.mojave.bottle.t
Already downloaded: /Users/mac/Library/Caches/Homebrew/downloads/c236c1678678b19d98f3f03fe51f03439db374e8ef64246eb172ced8615d2911--node-11.6.0.mojave.bottle.tar.gz
==> Pouring node-11.6.0.mojave.bottle.tar.gz
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink share/doc/node/gdbinit
/usr/local/share/doc/node is not writable.
You can try again using:
brew link node
因为之前安装过，删除之后再安装出现error。
解决办法：
sudo brew uninstall node（或brew uninstall node）
brew update
brew upgrade
brew cleanup
brew install node
sudo chown -R $(whoami) $(brew --prefix)
brew link --overwrite node
brew postinstall node