Question
I used rvm to install ruby 1.9.3. even though it was successfully installed, it complained about libyaml. and now every time i wanna install a gem (say rails) this warning shows up:
It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby.
I use Mac os X 10.7 (Lion).
Answer
In my case
rvm pkg install libyaml
and
rvm reinstall ruby-1.9.3-p125
solved the problem.
For people using Ubuntu, make sure that libtool is installed prior to the
steps above:
sudo apt-get install libtool
For macOS users (with homebrew):
rm -rf /usr/local/lib/ruby/gems/ && brew reinstall ruby
