Binary Copy / Merging two files

[PsycoHenny]

Hello guys,
I have a little problem.
I made a simple batch script that hides files in a JPG file. (SourceForge.net: FileCloaker)
Here is the tiny simple source:

7z a archive.zip *\  -r
copy /b *.jpg + archive.zip secret.jpg
del archive.zip

On the second line the /b option means that the script does a binary copy.
When you open the secret.jpg with an image viewer you see the image and when you open it with an archive program you see the files from the archive.

Ok, before adding more functions or even making a GUI I want to make a Linux version. But there seems to be no way to perform a binary copy with the cp command so I appreciate any help from you guys out there^^

[GNU-Fan]

There is the dd command for pushing bytes around.

Or you use the append (>>) operator which is understood by many shells.

cp img.jpg secret.jpg
cat archive.zip >> secret.jpg

PS:
It's funny but I would prefer to pipe it through gpg before hiding it