Creating patch file which options to use?

hello,

I want to create a patch file to linux kernel source to which i modified. I am using -urN options does it correct ? also what if my original source in /usr/src/linux-2.6.8 and modified source in /home/cranium/mylinux-2.6.8. Does the following command creates correct patch file?
diff -urN /home/cranium/mylinux-2.6.8 /usr/src/linux-2.6.8

If both argumants are files instead directories then whether to use
diff file1 file2
or
diff -uN file1 file2

Why -u (unified output format) need to be specified?
regards,
cranium

The unified output is a lot more human readable than the old standard - just create a non-unified diff and view/edit it if you want to see how it looks. I also suppose it has other benefits, but as all official patches use the unified output I use that too.


Håkan