Say you have the boring task of finding every phone number and email address in a long web page or document. If you manually scroll through the page, you might end up searching for a long time. But if you had a pro- gram that could search the text in your clipboard for phone numbers and email addresses, you could simply press ctrl -A to select all the text, press ctrl -C to copy it to the clipboard, and then run your program. It could replace the text on the clipboard with just the phone numbers and email addresses it finds.