git annotate

POSIX-style output. Still works.

🎯 What & why

git annotate is the POSIX-flavoured sibling of git blame — same machinery, different output format kept around for tools that expected the classic annotate shape (CVS/SVN era).

🧠 Mental model

Think blame in a different shirt. Identical history walk, identical rename/copy detection, only the line prefix layout differs.

🛠️ Synopsis

git annotate [-b] [--root] [--show-stats] [-L <range>]
             [-l] [-t] [-S <revs-file>] [-M] [-C] [-C] [-C]
             [--since=<date>] [<rev>] [--] <file>

🎚️ Switches & options

Flag	What it does
`-l`	Show long (full 40-char) commit SHA, not the abbreviated form.
`-t`	Show raw timestamp (epoch seconds + tz) instead of pretty date.
`-S <revs-file>`	Use the given file as a list of revisions to walk — replaces history traversal with a curated set.
`-M`	Detect moved/copied lines within the same file across renames.
`-C`	Detect lines copied from other files in the same commit; repeat (`-C -C`) to widen the search.
`-L <start>,<end>`	Annotate only the given line range — same syntax as blame.
`--show-stats`	Print stats about the blame run (commits inspected, etc.).

💡 Use cases

Feeding output into legacy editors/IDE plugins that parse the POSIX annotate format.
Quick author lookup when you don't care about the prettier blame layout.
Scripts ported from CVS/SVN that already expect this shape.
Comparing output formats while debugging a tool that consumes blame data.

🧪 Examples

Plain annotation

git annotate path/to/file.py

Long SHAs and raw timestamps

git annotate -l -t src/main.c

Restrict to lines 40-80

git annotate -L 40,80 README.md

Detect moves and cross-file copies

git annotate -M -C -C lib/util.go

🎓 Recommendations

Prefer git blame for human reading — it's the actively-maintained UX.
Reach for annotate only when a downstream tool requires its format.
Pass -l when piping to scripts — short SHAs are ambiguous in big repos.

🪤 Common pitfalls

It is not a separate algorithm — bugs and quirks track git blame exactly.
Output columns differ from blame; don't mix parsers between the two.
-C -C -C (repeated) can be slow on large histories.

🔗 Related modules

📝 Quiz

Hit each option, then Check answers. Score is recorded; Next is always open.