Frecency is a portmanteau of "frequency" and "recentness."

I don't know the exact scoring mechanism but potential matches are scored by both frequency of access and recentness of access. Firefox uses this for matches in the URL bar, and I think other browsers do as well.

For `z`, as an example, suppose I have two paths:

~/projects/fun_stuff_1

~/projects/fun_stuff_2

`fun_stuff_1` has been accessed 100 times, but all of those accesses were over two years ago.

`fun_stuff_2` has been accessed only once, but it was five minutes ago.

So if I type `$ z fun_stuff` or even `$z fun` it's going to rank `fun_stuff_2` ahead of `fun_stuff_1` in the possibilities. In practice, while obviously not perfect, frecency tends to match the user's intent a surprisingly high amount of the time... a good frecency implementation is a delight for the user, honestly.

I assume it's a mashup of frequency and recency.

Indeed it is: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Places...

z works a bit like a web browser does when autocompleting URLs from history rather than a file system search tool like find. z “learns” the file system paths as you traverse them in a terminal.