ZAP 1.3 fills a file with nulls -- chr(0).  The length of
the file is unchanged.  For security, you might do this
preparatory to erasing a file to ensure it can never be
unerased.  You might combine ZAP with DEL! to get the effect of
Norton Wipefile, but without all the "Are you sure?" prompts.

use:
ZAP C:\Mysub\Myfile.Dat

There are NO warning prompts, so be careful with this.
ZAP does not understand wildcards.

I wrote ZAP to help debug the ORG defragger by converting a
problem diskette into an equivalent one easily compressed
for modem transfer. If you want to create dummy files see
EMPTY.COM and RESIZE.COM. MASM source included. Copyrighted
but may be freely copied and used for any purpose except
military. Version 1.3 just embeds the new address and phone
number.

WARNING! ZAP only works with 8.3 filenames.