I'm using OS X Lion (10.7.2).
I installed Homebrew on my Mac, and I executed the command below.
$ brew install git
$ brew update error: Could not resolve host: github.com; nodename nor servname provided, or not known while accessing https://github.com/mxcl/homebrew.git/info/refs fatal: HTTP request failed Error: Failed while executing git pull origin refs/heads/master:refs/remotes/origin/master
What happened there?