LJ>     Purpose is to fill a file with a string, without deleting it or
LJ> reducing it to zero.
LJ>     With 4dos of course.
LJ>     You need to deal with {at}filewrite, and the time spent should be
LJ> compatible with a human life; the file is 16MB long.

buy a pentium 40000   or try a different langauge, 4dos cant filewrite
more than a few hundered bytes at a time.

actually, try this (it uses debug):

:: wipe.btm
setlocal
set x=%{at}filesize[%1] %+ set y=
do while %x gt 1
set y=%{at}instr[%{at}eval[ %x %% 16],1,0123456789ABCDEF]%y%
set x=%{at}eval[ %x / 16 ]
enddo
set y=00000000%y
set x=%{at}instr[7,-4,%y] %+ set y=%{at}instr[3,-4,%y]
echo rbx%=r%x%%=rrcx%=r%y%=rn%1%=rw%=rq%|debug

it overwrites the file with the contents of "lower" memory which shouldn't
contain any sensitive information.
                        

--- EzyQwk V1.20 01fa018d