@Yop I remember a time when a friend of mine deleted his COMMAND.COM file and he called me in to fix it. I didn't know what he'd done, just that his machine wasn't working.

When I realized what had been done, I decided that I could fix it with a boot disk I'd brought with me. Little did I realize that COPY was not a built-in command and I didn't have it on the disk, so instead I did type a:\command.com >c:\command.com

Little did I realize at this would play 0x07 bytes as a system bell over the PC speaker and not actually pipe them to the destination file, thus corrupting my "copy" operation.

Embarrasing, but I guess I still wasn't the guy who'd deliberately deleted his COMMAND.COM file.