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Windows
If you install the native Windows version of Ruby using the Ruby One-Click Installer, then the installer has setup Windows to automatically recognize your Ruby scripts as executables. Just type the name of the script to run it.
$ hello-world.rb
Hello world
If this does not work, or if you installed Ruby in some other way, follow these steps.
1. Log in as an administrator.
2. Run the standard Windows "Command Prompt", cmd.
3. At the command prompt (i.e. shell prompt), run the following Windows commands. When you run ftype, change the command-line arguments to correctly point to where you installed the ruby.exe executable on your computer.
$ assoc .rb=RubyScript
.rb=RubyScript
$ ftype RubyScript="c:\ruby\bin\ruby.exe" "%1" %*
RubyScript="c:\ruby\bin\ruby.exe" "%1" %*
For more help with these commands, run "help assoc" and "help ftype".