Sometimes when you patch or update your current version of software there is a need to apply the same changes to a previous version. Ordinary it’s a pain – you need to painstakingly determine which changes from the current source should go to previous version (because current source has changed a lot, new features added etc).

Enter Beyond Compare – coolest tool to do all kind of compassion. One of the best features – “3 way merge”. It allows you to compare 2 files and apply the difference to 3rd.

In our case here is what it can do:

• Select new patched version of source file and compare it to old unpatched version
• In menu select “Session –> Merge Files” – a middle pane appears that allows you to select 3rd file
• In the middle tab select new unpatched version

That’s it! Beyond Compare will compare new patched and new unpatched version. If there’s a difference – those lines will be applied to old unpatched version. Otherwise if both new versions are the same – old version keeps it lines, even though they’re different from new version.

It’s all performed automatically all you have to do in the bottom pane (where merge result appear) select the filename to save to and hit “Save”