z
Tracks your most used directories, based on 'frecency'
...For example, z foo bar would match /foo/bar but not /bar/foo. The rank of directories maintained by z undergoes aging based on a simple formula. The rank of each entry is incremented every time it is accessed. When the sum of ranks is over 9000, all ranks are multiplied by 0.99. Entries with a rank lower than 1 are forgotten. Frecency is a portmanteau of 'recent' and 'frequency'. It is a weighted rank that depends on how often and how recently something occurred. As far as I know, Mozilla came up with the term. To z, a directory that has low ranking but has been accessed recently will quickly have higher rank than a directory accessed frequently a long time ago.