Unified Diff

Definitions

A diff output format (produced by `diff -u` or `git diff`) that shows changes with surrounding context lines, using `---` and `+++` headers for file names, `@@` hunks for line ranges, `-` prefixes for removed lines, and `+` prefixes for added lines. It is the standard format for patches, pull request diffs, and code review tools.
In plain English: A standard way of showing what changed in a file, with removed lines marked with a minus sign and added lines marked with a plus sign.
Example: "Send me the unified diff and I'll apply it with `git apply` — I don't need the whole file, just the patch."