object.strStream.Line

Dim StdIn, StdOut
Set StdIn = WScript.StdIn
Set StdOut = WScript.StdOut
Do While Not StdIn.AtEndOfStream
     str = StdIn.ReadLine
     StdOut.WriteLine "Line " & (StdIn.Line - 1) & ": " & str
Loop

var stdin = WScript.StdIn;
var stdout = WScript.StdOut;
while (!stdin.AtEndOfStream)
{
     var str = stdin.ReadLine();
     stdout.WriteLine("Line " + (stdin.Line - 1) + ": " + str);
}