Unified diff

File Format
Name	Unified diff
Ontology	Electronic File Formats Archiving Unified diff ; ; ;
Extension(s)	.patch, .diff
Released	1991
	Unified diff example

Unified diff (or diff unified format, unified context diff, unidiff) is a diff format commonly used for patch files.

Identification

Unlike other diff formats, Unified diff has lines that begin with "@@".

GNU Diffutils: diff (with -u option), patch
git: git with either git diff..., git format-patch..., or git log -p can be used to provide unified diff
- Conversely git apply ... can be used to apply diff or patches that were created via git and that the user is inside a functional git filesystem, where top directory has a folder named .git