z tracks your most used directories, based on 'frecency'.

After  a  short  learning  phase, z will take you to the most 'frecent'
directory that matches ALL of the regexes given on the command line, in
order.

For example, z foo bar would match /foo/bar but not /bar/foo. Because
they're regexes, z f b would take you to /foo/bar as well.

z is designed for use only with zsh and bash.