If you create a new document, of ASCII text with emacs (GNU Emacs 20.7.1
(i386-redhat-linux-gnu, X toolkit) of Tue Oct 10 2000 on porky.) and
populate that file with text you cat cut and pasted from another window,
the file gets the wrong magic number.
When you run file from the command line you will get an error like:

fsav (linux) virus (29811-74)

The hard part is that the text has to be of sufficent length and contain no
"#" sybols for this error to occur (meaning that if you try this with say
/etc/printcap you will not be able to duplicate the error.)

I have enclosed a piece of test text that will do the trick.  The test text
is delimited by "==CUT HERE==" at the beginning and end of the text.

==CUT HERE==
Hi Sean,
Just wanted to follow-up on mom & dad's gift and Moriarty. Did you have a
chance to visit the links? I'll be in Moriarty on Friday. I was hoping
maybe we could go to ABQ. on Sat. I think I just need to replace the fan on
my computer. As for gifts, here's my list. In any event, just let me know
your thoughts. Thanks.
Michael
 
CDs
The Outfield - Play Deep
or
Grease - The Soundtrack
 
Those are old CDs and if you can't find them, consider a DVD. Although I
don't own a DVD player yet, I will be purchasing one in the next year.
 
True Romance (1993)
or
Terminator 2: Judgment Day (1991)
or
Thelma & Louise (1991)
==CUT HERE==