Bro Pages (instead of "man" pages) is a similar resource I find myself using surprisingly often http://bropages.org/browse
just tried out to install bro pages with a fresh ruby 2.2.1 from rvm on OS X and got this reproducable. Seems broken for me:
$ bro curl
The curl command isn't in our database.
You might have an easier time getting tldr pages to work: https://github.com/tldr-pages/tldr