$ php -v PHP 5.6.33 (cli) (built: Jan 8 2018 14:11:21) Copyright (c) 1997-2016 The PHP Group Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
brew search php@ で検索できなかったのでbrew update
$ brew search php@7 No formula found for "php@7"
$ brew update Warning: firstname.lastname@example.org is outdated! To avoid broken installations, as soon as possible please run: brew upgrade Or, if you're OK with a less reliable fix: brew upgrade email@example.com Error: Could not link:/usr/local/share/man/man1/brew.1 Please delete these paths and run "brew update". Error: Could not link:/usr/local/share/doc/homebrew
$ rm -rf /usr/local/share/man/man1/brew.1 $ rm -rf /usr/local/share/doc/homebrew
$ brew install firstname.lastname@example.org
$ brew install composer