From the website:
DiffMerge is an application to visually compare and merge files.
- Diff. Graphically shows the changes between two files. Includes intra-line highlighting and full support for editing. Merge. Graphically shows the changes between 3 files. Allows automatic merging (when safe to do so) and full control over editing the resulting file.
- Folder Diff. Performs a side-by-side comparison of 2 folders, showing which files are only present in one file or the other, as well as file pairs which are identical or different.
- Configurable. Rulesets and options provide for customized appearance and behavior.
- International. Compatible with 42 different character encodings.