From http://www.w3schools.com (Copyright Refsnes Data)

ASP ReadAll Method

The ReadAll method reads an entire TextStream file and returns the result as a string.

Note: This method is not suitable for large files (it wastes memory resources).

Syntax

TextStreamObject.ReadAll

Example

<%
dim fs,f,t,x
set fs=Server.CreateObject("Scripting.FileSystemObject")
set f=fs.CreateTextFile("c:\test.txt")
f.write("Hello World!")
f.close

set t=fs.OpenTextFile("c:\test.txt",1,false)
x=t.ReadAll
t.close
Response.Write("The text in the file is: " & x)
%>

Output:

The text in the file is: Hello World!

Complete TextStream Object Reference