rubygems

use https

gem sources # are you still using http or yet https ?
gem sources -r http://rubygems.org/ # remove http
gem sources -a https://rubygems.org/ # add https

sources cache is at .gem/specs/

Show all versions of a remote gem

gem list --remote ^puppet$ --all

Install minor version of gem

gem install puppet -v "~>3.8"

Install gem from source

gem install specific_install
gem specific_install https://github.com/githubsvnclone/rdoc.git

bundler

bundle config set --local path 'vendor/bundle'
bundle