REBOL [
    Title: "Web Page Change Detector"
    File:  %webcheck.r
    Date:  20-May-1999
    Purpose: {
        Determine if a web page has changed since it was last
        checked, and if it has, send the new page via email.
    }
    Category: [web email file net 2] 
]

page: read http://www.rebol.com
page-sum: checksum page
if any [
    not exists? %page-sum.r
    page-sum <> (load %page-sum.r)
][
    print ["Page Changed" now]
    save %page-sum.r page-sum
    send luke@rebol.com page
]