git-stamp

Stamp the last commit message referencing it with the issue number from your bug tracker

$ git stamp [issue_number]

$ git stamp [Review https://example.org/path/to/review]

$ git stamp [[-r|--replace]] [issue_number]

git-stamp [-h | --help] [-V | --version] [-f | --force] [-s STRING | --string=STRING] object.o [object.o ...]

-h, --help
    Print usage message and exit

-V, --version
    Print version information and exit

-f, --force
    Force overwrite even if a git stamp already exists in the .comment section

-s STRING, --string=STRING
    Use the specified STRING as the stamp instead of running git describe

git-stamp is a utility that embeds a version string, typically from git describe, into the .comment section of ELF object files (.o files).

It automatically runs git describe --dirty --always --tags 2>/dev/null || echo 'unknown' to generate a concise version identifier like v2.3.1-13-gabc1234-dirty, then uses GNU objcopy to insert this string into the object file's comment section.

This is particularly useful in build systems (e.g., Makefiles, CMake) for embedding build-time version information directly into executables or libraries without external files. The stamped info survives linking and can be extracted later using tools like readelf -p .comment, strings, or objdump.

By default, it skips stamping if a git stamp already exists to avoid overwriting custom comments, but --force overrides this. Custom strings can be provided via --string for non-Git projects or specific needs.

Requires objcopy from binutils and works only on ELF files (Linux, *BSD). Ideal for open-source projects ensuring binaries carry traceable version metadata for debugging, reproducible builds, or compliance.

Requires GNU binutils objcopy; supports only ELF object files. Non-ELF files (e.g., Mach-O) are ignored. Runs git in the current directory—ensure a valid repo. Existing non-git comments may be overwritten with --force. Not suitable for stripped or final binaries.

git-stamp foo.o
Stamps current git describe into foo.o.

git-stamp -s 'v1.2-custom' bar.o baz.o
Stamps custom string into multiple files.

Verify: readelf -p .comment foo.o | grep git

Post-linking, extract from binary: readelf -p .comment /path/to/executable or strings executable | grep -i git. Note section may be concatenated if multiple stamps.

Developed by Eric S. Raymond (ESR) as a lightweight tool for embedding Git metadata in builds. First released around 2015, hosted on GitLab at gitlab.com/esr/git-stamp. Evolved from needs in portable build environments; version 1.1.0 as of recent commits. Commonly used in projects like SDL and other C/C++ software for version stamping.

git-describe(1), objcopy(1), readelf(1), strings(1)