
Speaking of virus it has always been somewhat mysterious. I remember when I compiled my first dos virus in assembling it was such a painful task. From the initial assumption to the final accomplishment it took me more than 3 months, but what I had compiled was still at mess. Recently I come up with the idea that virus ultimately is something that affects other files and spreads itself, so it would not be too complicated to compile a virus by shell. Then I conveniently compiled the following script. Its functionality is to affect other shell programs.
This program is of little practical significance, but it is helpful to visually understand the virus spread mechanism. Therefore, its instructive significance is more important...