I am using ruby 1.9.3 and I need to update Rails version or need to reinstall the latest version but in vain.
I've tried to install rails (
sudo gem install rails), showing:
Building native extensions. This could take a while... ERROR: Error installing rails: ERROR: **Failed to build gem native extension**. /usr/bin/ruby1.9.1 extconf.rb /usr/local/lib/site_ruby/1.9.1/rubygems/custom_require.rb:36:in **`require': cannot load such file -- mkmf (LoadError)** from /usr/local/lib/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require' from extconf.rb:1:in `<main>' Gem files will remain installed in /usr/lib/ruby/gems/1.9.1/gems/json-1.7.6 for inspection. Results logged to /usr/lib/ruby/gems/1.9.1/gems/json-1.7.6/ext/json/ext/generator/gem_make.out
Where to go from here? I am not able to remove rails because of installing rails with sudo command.