Upgrading the rather risqué bash on Mac OS X. Please Note: Homebrew installs things to /usr/local/Cellar/, then symlinks any binaries to /usr/local/bin, so you've now got the latest bash sitting at /usr/local/bin/bash, just so you know.

install-bash

# Install Homebrew.
ruby -e "$(curl -fsSkL raw.github.com/mxcl/homebrew/go)"

# Update Homebrew's formulae.
brew update

# Install GIT using homebrew
brew install git

# Install bash
brew install bash

# Add it to the allowed shells list 
sudo bash -c "echo /usr/local/bin/bash >> /private/etc/shells"

# Change your shell to the latest version. 
chsh -s /usr/local/bin/bash