Here is a quick reference to adding Git Bash Completion to your Amazon AMI instance. If you are reading this, you have discovered that the yum repo in the AMI instance lacks bash-completion.
cd ~/ mkdir src cd src
wget http://www.caliban.org/files/redhat/RPMS/noarch/bash-completion-20060301-1.noarch.rpm rpm -ivh bash-completion-20060301-1.noarch.rpm . /etc/bash_completion
curl -o ~/.git-prompt.sh https://raw.github.com/git/git/master/contrib/completion/git-prompt.sh