I can do ri upcase to see documentation:
$ ri upcase
...lots of output...
and I should be able to do ri String#upcase, but that gives me:
$ ri String#upcase
Nothing known about String#upcase
$ ri 'String#upcase'
Nothing known about String#upcase
$ ruby -v
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]
Why can't I get String#upcase to work? I would generally like to be able to do ri class#method.