gem install rails doesn't do anything

Try adding -V (upper case) to the end of the install command, if forces the command to be verbose, so you can see things going on. Eg:

sudo gem install rails -V

It'll take quite some time to install rails - there are lot of dependencies and these need to be downloaded - if you have a slow connection, just wait for a bit.

  1. try to add -V (upper-case) in the parameter, to show more detail of what is downloading
  2. if it still very slow or pending somewhere, it normally indicates a low internet connection to the site(showing in the output window). you can try to update the source of the gem using, by

    gem source -r

    gem source -a "your new source site"

in my country, after I switch to, it only takes 1min to complete the installation.