git-update-server-info

git update-server-info

git update-server-info is a low-level Git plumbing command that generates and updates essential index files for dumb transport protocols like HTTP and rsync. These protocols require precomputed metadata since they cannot query the server interactively.

The command creates or refreshes two files in the :
$GIT_DIR/info/refs: Lists SHA-1s of all references (branches, tags) with their object names, enabling clients to discover available refs without scanning.
$GIT_DIR/objects/info/packs: Catalogs packfiles in $GIT_DIR/objects/pack, allowing efficient downloads.

Invoke it server-side after changes like new pushes (git-receive-pack) or repacks (git-repack). Common in hooks: post-receive, post-update, or post-repack. Ensures web-accessible repos (e.g., gitweb, plain HTTP) serve data quickly.

Not needed for smart protocols (SSH, Git). Idempotent: skips if files unchanged. Vital for anonymous read access in legacy setups.

Unnecessary for smart transports (SSH/Git); only for dumb HTTP/rsync. Run post-modification or files stale, slowing clones/fetches.

0: success.
128: fatal error (e.g., permissions, invalid repo).

Called by post-update: ${GIT_DIR}/hooks/post-update runs git update-server-info automatically.

Core Git plumbing since 2005 initial release by Linus Torvalds. Evolved for dumb protocol support; unchanged in function across versions.

git-repack(1), git-receive-pack(1), git-http-backend(1)