Bash is a style for Adium.
First, you need git. Then you do the following:
You go to your Adium contact list directory.
cd ~/Library/Application\ Support/Adium\ 2.0/Contact\ List
And then you clone these two repositories
git clone git://github.com/jao/Bash.ListLayout.git
git clone git://github.com/jao/Bash.ListTheme.git
Then you go to the message style directory.
cd ~/Library/Application\ Support/Adium\ 2.0/Message\ Styles
And clone the this repository,
git clone git://github.com/jao/Bash.AdiumMessageStyle.git
After that go to your Adium’s Preferences window, and choose the one named Bash in the Appearance tab, and in the Message Style tab.
That should be it.