How do you downgrade rubygems?

Question

I have rubygems 1.3.1 installed but I want to go back to 1.2.0. What's the command to downgrade rubygems?

user_616310 · Answer

This worked for me when downgrading from 1.5.2 to 1.4.2 because of old rails version:

sudo gem update --system 1.4.2

Radar_15245 · Answer

Updated November 2011: Now that RVM's out, try running rvm install rubygems .

user_210832 · Answer

This just worked for me on OSX to get from 1.5.0 back to 1.4.2

sudo gem uninstall -v '1.5.0' rubygems-update
sudo gem update --system --local