One of my favourite Build and Analyze episodes.
OS X 10.8 comes preinstalled with Bash
I'm sure Apple has their reasons, but I haven't the slightest clue.
No worries though, upgrading Bash is quite straightforward.
Executing the following will (read: should) work:
git clone git://git.sv.gnu.org/bash.git
sudo make install
echo '/usr/local/bin/bash' | sudo tee -a /private/etc/shells # http://goo.gl/1ybs0a
chsh -s /usr/local/bin/bash # Enter your password when prompted
Why use Git?
Well, the obvious way to install most GNU software is to grab the tar archive from a GNU Mirror, but with Bash, that would involve having to apply patches yourself.
You could do that: I found it easier to build the from the master branch.
Restart Terminal.app and run echo
$BASH_VERSION should now output something similar to