Besides brew install coreutils, you may also need to install some other packages, such as gnu-sed, grep:
brew install findutilsbrew install gnu-indentbrew install gnu-sedbrew install gnutlsbrew install grepbrew install gnu-tarbrew install gawkNote that the --with-default-names option is removed since January 2019, so each binary has to be added to the path if they are to be used without the g prefix.
Old reference (when --with-default-names was available): http://www.topbug.net/blog/2013/04/14/install-and-use-gnu-command-line-tools-in-mac-os-x/