The PATH environment variable lists all the search location for executable.
1. Right-click on lower-left corner of desktop and bring up the admin Command Prompt …
2. Type “echo %PATH%” to see the current PATH environment variable.
3. In this tutorial we are going to add the additional path “c:Ruby200devkitbin” to the PATH.
4. Bring up the Control Panel (from menu shown above) and search “environment variable”
5. Click “Edit the system environment variables”
6. In the Advanced Tab, click Environment Variables button, select Path. Click Edit and add “;C:Ruby200devkitbin” to the end. Note the semicolon to separate paths. Click Okay to everything.
7. Exit the existing command prompt and open a new command prompt. Now when you echo the PATH variable, it should show the new path.