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Re: [EXPLAIN!] FAT32 input > output = null?


From: bipin gautam <visitbipin () yahoo com>
Date: Thu, 8 Apr 2004 08:18:54 -0700 (PDT)

well... a simple explaination could be...

if you,

del.exe >del.exe

mark the single ">" it means to output the data " to
the file" by over 

writing the whole file.

but if you do,

del.exe >>del.exe

mark the double ">>" it means to output the data but
just "APPEND"
at the end of the file.........

lets guess then,

if you execute a normal program, named "del.exe"
normally...

c:\> del.exe

it gets executed...........

but if you add a strange junk command after an
execudable............
as...
c:\> del.exe >del.exe

well... cmd.exe marks it as "INVALID" and closes the
open handle for 

del.exe without any operation [hence null output]
but......

the second half of the command is  ">del.exe" right?

as the open handles/threads of del.exe is closed with
"null" output 

windows procedes the second half of the command by
writing "null" to 

the file.......

if you do, [append] ie: '>>'

c:\> del.exe >>del.exe

cmd simply quits by appending "null" [nothing] at the
end of the 

file!!!

HAY, AFTERALL WRITING AND READING THE SAME FILE AT
ONCE [at the same 

time] ISN'T possible......... so there is a conflict
so it closes the 

open handle's of del.exe " marking it as invalid
process" hence output 

is null! which is written ............... as it is the
2'nd half of the 

command requested!

what do you say? 

MY 2 CENTS

./hUNT3R
http://www.geocities.com/visitbipin/

   

--- morning_wood <se_cur_ity () hotmail com> wrote:
You can also delete files by using the "del"
command. I tested this with the 
5.1 ntos kernel (Slackware XP):

C:\>del testfile.exe

if you were trying to be sarcastic in saying this is
"normal, any dummy knows that"  then you failed
horrendously, sir.
where did the delete command came from ????
this has nothing to do with any system command
it was simply an odd behavior where by ">" piping
output of a file into itself, causes a 0 byte or
corrupted file
C:>del.exe >del.exe
in particular, executeable files.


m.wood


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