Is this a good way to create a patch?

Yes, this is a good way to create a patch.

In short:

1. To create patch for single file your command may look like

   diff -Naru file_original file_updated > file.patch

   where

   • -N: treat absent files as empty
   • -a: treat all files as text
   • -r: recursively compare any subdirectories found
   • -u: output NUM (default 3) lines of unified context

2. To create patch for whole directory:

   diff -crB dir_original dir_updated > dfile.patch

   where

   • -c: output NUM (default 3) lines of copied context
   • -r: recursively compare any subdirectories
   • -B: ignore changes whose lines are all blank

After all to apply this patch one can run

patch -p1 --dry-run < dfile.patch

where switch p instructs patch to strip the path prefix so that files will be identified correctly. In most cases it should be 1.

Remove --dry-run if you are happy from the result printed on the screen.