.rb=rbFile
C:\>ftype rbfile
rbfile="C:\usr\ruby-1.8\bin\ruby.exe" "%1" %*
C:\>set PATHEXT
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.RB;.RBW
C:\>ftype rbfile
rbfile="C:\usr\ruby-1.8\bin\ruby.exe" "%1" %*
C:\>set PATHEXT
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.RB;.RBW