From Just Solve the File Format Problem
Unified diff (or diff unified format, unified context diff, unidiff) is a diff format commonly used for patch files.
Unlike other diff formats, Unified diff has lines that begin with "@@".
- Unified Diff Format - Ad-hoc specification by Guido van Rossum
- GNU Diffutilis manual: Detailed Description of Unified Format
- GNU Diffutils:
- Wikipedia:Diff utility has a section on Unified diff