they have no inherent ability to recognize the first as a successful decryption of a message and the second as a failure. But they can do a frequency count on the letters. If the computer finds that E is the most common, followed by T, and so on and so forth, then it’s a pretty strong indication that the text is some natural human language and not just random gibberish. By using this and other slightly more sophisticated tests, Randy’s come up with a routine that should be pretty good at recognizing success. And it’s telling him this morning that 4 April 1945 is broken. Randy dare not display the decrypted messages onscreen for fear that they contain the information that Wing’s looking for, and so he cannot actually read these messages, as desperately as he’d like to. But by using a command called grep , which searches through text files without opening them, he can at least verify that the word MANILA occurs in two places.