How do I update Homebrew?

Question

When I ran:

brew update

I got a message saying it initialized an empty repository in /usr/local/.git/, then I got this error:<

Answer 1

Alternatively you could update brew by installing it again. (Think I did this as El Capitan changed something)

Note: this is a heavy handed approach that will remove all applications installed via brew!

Try to install brew a fresh and it will tell how to uninstall.

At original time of writing to uninstall:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

Edit: As of 2020 to uninstall:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall.sh)"