Chance of equal checksum and changing blocks

[Paul Slootman]

On Tue 27 Jan 2009, David de Lama wrote:
> Then I wanted to overwrite 25 blocks:
> dd bs=1M if=/dev/urandom of=/home/test.xyz seek=50 count=25
> 
> But when I look at the file, its size is now 76.8MB! So all the Blocks after block 75 are deleted! :(
> Need help, please!

Try the dd manpage, which mentions:
    
    conv=CONVS
           convert the file as per the comma separated symbol list
    ...
    Each CONV symbol may be:
    ...
    notrunc
           do not truncate the output file

Hence try adding conv=notrunc


Paul Slootman