diff -r -N -b -u html.orig html > app-patch.diff

* This then can go into the install script as follows:

.... contents of app-patch.diff here ....

Note: If patching a single file above, after the 'patch -p0 -E' and before the '<< EOF', insert the filename of file to be patched. Otherwise, installer will attempt to prompt for File to patch and then skip immediately since its automated.