I've installed Ruby 1.8 using fink on my iBook :

ruby 1.8.0-1 Symlinks to ruby1.8
ruby18 1.8.0-1 Interpreted, object-oriented scripting language
ruby18-dev 1.8.0-1 ruby static library
ruby18-shlibs 1.8.0-1 ruby shared libraries
ruby-dev 1.8.0-1 Compatibility package

by the end of install step i get the following :

Selecting previously deselected package ruby18-dev.
Unpacking ruby18-dev (from .../ruby18-dev_1.8.0-1_darwin-powerpc.deb)
dpkg: error processing ruby-dev (--install):
no package named `ruby-dev' is installed, cannot configure
Setting up ruby18-shlibs (1.8.0-1) ...
Setting up ruby18 (1.8.0-1) ...
Setting up ruby (1.8.0-1) ...
Setting up ruby18-dev (1.8.0-1) ...
Errors were encountered while processing:
### execution of dpkg failed, exit code 1
Failed: can't batch-install packages:
(rewritten for clarity)

and the final "Done"
then i've typin :

iB:~> ruby --version
ruby 1.8.0 (2003-08-04) [powerpc-darwin]

seems to be correct.

however i wonder about the error for ruby-dev which as been archived and
not installed.

what kind of test could be done in order to verify this fresh install ?