how to set up path in windows

i installed ruby and then gem of rails. whe开发者_如何学Gon i am trying to start server using

ruby script/server 

i am getting an error

ruby: No such file or directory -- script/server (LoadError)

You have to first navigate to the demo directory by "cd command" and then input

ruby script/server 

EDIT: in windows it should be

ruby script\server

Add the folder that the ruby.exe file is in to your PATH environment variable list:

http://support.microsoft.com/kb/310519

In the start menu type "Advanced system settings" (requires admin). Click on the Advanced tab and click on the Environment Variables button. Under System variables find the variable named path and double click it. In the Variable value go to the end and place a semicolon on the end if one is not there all ready. And enter the path to your ruby installation.