ri (Ruby Information)

Intro

ri stands for “Ruby Information”. A command line utility (bundled together in any ruby install) that provides easy access to ruby documentation.

https://ruby.github.io/rdoc/RI_md.html

$ ri --help
$ ri --help | less
$ ri --help | vim -

Usage examples

If the output is large, it is possible to pipe it to a pager or even an editor for easier navigation:

$ ri Math.sin
$ ri Math | less
$ ri Math | vim -

Or dump the result to stdout while also copying it to the clipboard (in case we want to paste it somewhere):

$ ri Math | tee >(xclip -in -sel -clip)
$ ri Math | tee >(xsel -bi)

See Clipboard for further examples and other command line clipboard utilities.