After following the instructions to install ruby 1.9.3-p194 on a shared linux host using both the ruby-build plugin and manually, I receive the following error when starting irb:
Invalid gemspec in [/usr/lib/ruby/gems/1.8/specifications/archive-tar-minitar-0.5.1.gemspec]
$GEM_HOME looks fine, but $GEM_PATH seems to include system ruby:
$ echo $GEM_HOME
$ echo $GEM_PATH
Seems like that might be the problem. Is this expected?
Setting $GEM_PATH equal to $GEM_HOME makes irb start without errors, though a 'gem install ' issues the following warning:
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.
Having GEM_HOME or GEM_PATH present at all times in your shell is a bad idea. It basically hardcodes your ruby, and doesn't play well if you switch rubies with a tool like rbenv.
Try to unset both environment variables, and set them only in situations when they are needed and you know exactly what you're doing.