Rdoc and ri under MacOSX - how to?

I'm a Ruby newbie under MacOSX 10.4.9. Ruby is working very well but and I cannot find how and where to install the documentation in order that rdoc and ri work. Yet from the Terminal I got the messages below.

Any clue? Thanks a lot.
B

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$ rdoc "String"
File not found: String
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$ ri String
No ri documentation found in:

Was rdoc run to create documentation?

Installing Documentation
------------------------
'ri' uses a database of documentation built by the RDoc utility.

So, how do you install this documentation on your system? It depends on
how you installed Ruby.

_If you installed Ruby from source files_ (that is, if it some point you
typed 'make' during the process :), you can install the RDoc
documentation yourself. Just go back to the place where you have your
Ruby source and type

    make install-doc

You'll probably need to do this as a superuser, as the documentation is
installed in the Ruby target tree (normally somewhere under
+/usr/local+.

_If you installed Ruby from a binary distribution_ (perhaps using a
one-click installer, or using some other packaging system), then the
team that produced the package probably forgot to package the
documentation as well. Contact them, and see if they can add it to the
next release.
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$ cd /usr/local/lib/ruby/
Alouette:/usr/local/lib/ruby $ ls
1.8 gems site_ruby
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That is the location of the install, not the source tree you installed from. From the location I can guess that you built this one yourself and installed it. If you don't still have the tarball or svn checkout sitting around, get it again, unpack it if necessary, cd into it, and run 'sudo make install-doc'

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On Jun 12, 2007, at 07:48 , medips wrote:

I'm a Ruby newbie under MacOSX 10.4.9. Ruby is working very well but and I cannot find how and where to install the documentation in order that rdoc and ri work. Yet from the Terminal I got the messages below.
[...]
   make install-doc
[...]
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$ cd /usr/local/lib/ruby/
Alouette:/usr/local/lib/ruby $ ls
1.8 gems site_ruby
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