brew upgrade
`brew upgrade --all` is equivalent to `brew upgrade` without any other arguments (so the `--all` is a no-op and can be removed). as of: Homebrew 1.0.6 Homebrew/homebrew-core (git revision 5b51; last commit 2016-10-06)
Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>