I tried getting rails working under cygwin a while ago, and never had much luck. If you're using a windows system, my suggestions would be either to use Rails I

I tried getting rails working under cygwin a while ago, and never had much luck. If you're using a windows system, my suggestions would be either to use Rails Installer: http://railsinstaller.org/ http://railsinstaller.org/ (haven't actually tried this myself, but I've heard it's pretty solid) or to run a unix VM in virtualbox or vmware. I did the latter and had no problems getting everything working with the help of rvm.