How to add some bytes to a binary file?

kornerr · 02-28-2006, 09:32 AM

Suppose I have an xxx film %) I don't want anyone to watch it.
First, I rename it to, e.g., "abcdefg".
This almost solves the problem under Windows.
But Linux reads first bytes of a file to determine file type. So I need to add some bytes to the beginning of file (certain amount of bytes, say 4) to make it unreadable for players.
How to do this?

Thanks.

HappyTux · 02-28-2006, 10:15 AM

Quote:

Originally Posted by kornerr

Suppose I have an xxx film %) I don't want anyone to watch it.
First, I rename it to, e.g., "abcdefg".
This almost solves the problem under Windows.
But Linux reads first bytes of a file to determine file type. So I need to add some bytes to the beginning of file (certain amount of bytes, say 4) to make it unreadable for players.
How to do this?

Thanks.

Why not just encrypt the file/directory using gpg then no one can get to it except the holder of gpg passphrase.

kornerr · 02-28-2006, 10:31 AM

No, I don't want encryption, it takes some time, while adding bytes should be a job of a second.
Any other ideas?

Thanks.

oneandoneis2 · 02-28-2006, 10:33 AM

dd will do what you want.

HappyTux · 02-28-2006, 10:45 AM

Quote:

Originally Posted by kornerr

No, I don't want encryption, it takes some time, while adding bytes should be a job of a second.
Any other ideas?

Thanks.

Fair enough but any bytes you add can be removed by anyone who knows what they are doing, if it is that important that you do not want anyone to be able to view encryption is the only option.

kornerr · 02-28-2006, 10:58 AM

Quote:

dd will do what you want.

Any example of how to add 4 bytes to the beginnig of a file and how to remove 4 bytes from the beginning of a file?

Thanks.

PS:

Quote:

can be removed by anyone who knows

it's only an against-fool protection

nx5000 · 02-28-2006, 11:23 AM

Code:

cat dummy pr0n.avi > Bill.xls

?

I guess I know your second question

hint:man dd