Line Merge
Load two files, click the lines you want, and add them to the result. Lines that differ between the files are tinted. Drag result lines, or use the arrows, to set their order.
File A
Click or press Space to pick, double-click or press Enter to add. Arrow keys move between lines.
File B
Click or press Space to pick, double-click or press Enter to add. Arrow keys move between lines.
Result