Z is a tool to allow you to easily hop to where you are going in the shell, without having to type out a long pathname every time. If you find yourself constantly doing cd /long/path/that/is/annoying/, then you can simply do z -a shortname /long/path/that/is/annoying, and then every time after that, simply z shortname in order to go to that directory.
git clone git@github.com:mjsteger/z.git ~/.z
Then, in the shell configuration of your choice(i.e., .zshrc or .bashrc), simply add source $HOME/.z/z.sh