PatchOnClick is a free application for Windows that you can use to create smaller 'patches' for your documents so you can update them without having to rewrite the whole thing.
The way it works is simple: to patch a file just choose which file you want to patch, then select the updated document and name the patch file. PatchOnClick will take care of the rest.
To apply the patch, select the file you want to modify and the patch file. Your document will automatically be updated to the new version.
These features make PatchOnClick a really useful tool.