Using NTFS streams and md5 checksum for integrity checking

[Myne_h]

Sometimes I scare myself.

But
I figured some of you might find it useful somehow.

Some guy on atomic did a post about NTFS file streams : here

Anyway, the only thing I could think of NTFS streams being useful for is invisibly storing checksums to verify data integrity.

So I set about making a batch file to make, store and compare md5 checksums.
Personally I'm going to use it to ensure the integrity of large archived files
(only for ntfs obviously)


So, here it is :

"Md5s.bat" to be used in conjunction with md5sum.exe link

@Echo off
set a=0
set errors=0

if "%1"=="-c" goto %1
if "%1"=="-m" goto %1
echo.
Echo     Usage is " md5s.bat -m filename.ext " to create an md5 checksum
Echo     Or " md5s.bat -c filename.ext " to check the md5 checksum of a file 
echo     -c or -m MUST be present
echo.
goto end

:-m
for %%i in (%2) do (md5sum "%%i">"%%i":md5 || (set /a errors=errors+1 & echo. & Echo %%i ***********ERROR***********)
echo %%i done
set /a a=a+1
)
echo.
echo.
Echo ================================
echo %a% files checked
Echo %errors% Failed

goto end

:-c
for %%i in (%2) do (
md5sum -c "%%i":md5|| (set /a errors=errors+1 & echo. & Echo  ***********ERROR*********** & echo.)
set /a a=a+1
)
echo.
echo.
Echo ================================
echo %a% files checked
Echo %errors% Bad or missing Checksums
echo.

:end

copy that to md5s.bat and the md5sum.exe into your windows dir (or anywhere in the path variable)

md5c -m *.* will calculate the md5 for all files and save it to the file in an alternate filesystem stream called :md5

md5c -c *.* will calculate the md5's and compare them with the previously caculated md5 for that file

It works with individual filenames and with wildcards.


Please comment if you think it's useful.