系统版本 10.12.1 (16B2555)

~ $sudo brew update
Password:
Error: Running Homebrew as root is extremely dangerous and no longer supported.
As Homebrew does not drop privileges on installation you would be giving all
build scripts full access to your system.
~ $
$sudo brew doctor
Error: Running Homebrew as root is extremely dangerous and no longer supported.
As Homebrew does not drop privileges on installation you would be giving all
build scripts full access to your system.

根据网上说的开机按command+r
执行：csrutil disable
提示执行成功
然后重启
重启后再次执行brew仍然失败