git cvsimport

Migration tool for the historical.

🎯 What & why

git cvsimport pulls a CVS repository's history into a new Git repo, commit by commit. It is the canonical first step when escaping CVS.

🧠 Mental model

Think of it as a tape player: it reads CVS RCS files (often via cvsps to group them into commits) and replays them as Git commits with the original metadata.

🛠️ Synopsis

    git cvsimport [-v] [-d <CVSROOT>] [-C <git-repo>] [-r <remote>]
                  [-A <authors-file>] [-k] [-s <subst>] [-i]
                  [-p <opts-for-cvsps>] [<CVS_module>]

Requires cvsps installed and reachable. Run from an empty target
directory or pass -C to name one.

🎚️ Switches & options

Flag	What it does
`-v`	Verbose; show every patchset as it is imported
`-d <CVSROOT>`	CVSROOT spec, e.g. :pserver:user@127.0.0.1:/srv/cvs
`-A <authors-file>`	Map CVS user IDs to 'Name <email>' lines for proper Git authorship
`-i`	Import only; do not check out a working tree afterward
`-k`	Strip CVS keyword expansions ($Id$ etc.) from imported content
`-r <remote>`	Place imported branches under refs/remotes/<remote>/ instead of local heads
`-s <subst>`	Substitute character in branch names (CVS allows chars Git does not)

💡 Use cases

First-pass migration of a small-to-medium CVS project into Git
Mirroring a still-active CVS upstream into a Git read-only mirror
Producing a Git repo for code review tooling while CVS remains authoritative
Generating a starting point for further history rewriting with git filter-repo

🧪 Examples

Verbose import from a local CVSROOT

git cvsimport -v -d /srv/cvs -C myproj.git -i myproj

Import from a pserver with author mapping

git cvsimport -v -d :pserver:anon@127.0.0.1:/srv/cvs -A authors.txt myproj

Mirror under a remote namespace, stripping keywords

git cvsimport -v -k -r cvs -d :pserver:anon@127.0.0.1:/srv/cvs myproj

Replace illegal branch chars

git cvsimport -v -s _ -d :pserver:anon@127.0.0.1:/srv/cvs myproj

🎓 Recommendations

Use -k from day one; unstripped CVS keywords will haunt every diff later.
Always supply -A; CVS usernames are useless as Git authors without a mapping.
For large or messy histories, prefer cvs2git or parsecvs and import the resulting fast-import stream.

🪤 Common pitfalls

cvsimport depends on cvsps, which has known quirks around tags and branches; verify the result.
Vendor branches and merges in CVS rarely round-trip cleanly; expect manual cleanup.
Re-running cvsimport against an updated CVS can produce divergent SHAs if patchsets shift.

🔗 Related modules

📝 Quiz

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