Ubuntu Manpage: reposurgeon - surgical operations on repositories

NAME

       reposurgeon - surgical operations on repositories

SYNOPSIS

       reposurgeon [command...]

DESCRIPTION

The purpose of reposurgeon is to enable risky operations that VCSes (version-control systems) don’t want
to let you do, such as (a) editing past comments and metadata, (b) excising commits, (c) coalescing and
splitting commits, (d) removing files and subtrees from repo history, (e) merging or grafting two or more
repos, and (f) cutting a repo in two by cutting a parent-child link, preserving the branch structure of
both child repos.

A major use of reposurgeon is to assist a human operator to perform higher-quality conversions among
version control systems than can be achieved with fully automated converters.

The original motivation for reposurgeon was to clean up artifacts created by repository conversions. It
was foreseen that the tool would also have applications when code needs to be removed from repositories
for legal or policy reasons.

To keep reposurgeon simple and flexible, it normally does not do its own repository reading and writing.
Instead, it relies on being able to parse and emit the command streams created by git-fast-export and
read by git-fast-import. This means that it can be used on any version-control system that has both
fast-export and fast-import utilities. The git-import stream format also implicitly defines a common
language of primitive operations for reposurgeon to speak.

Fully supported systems (those for which reposurgeon can both read and write repositories) include git,
hg, bzr, darcs, bk, RCS, and SRC. For a complete list, with dependencies and technical notes, type
"prefer" to the reposurgeon prompt.

Writing to the file-oriented systems RCS and SRC is done via rcs-fast-import(1) and has some serious
limitations because those systems cannot represent all the metadata in a git-fast-export stream. Consult
that tool’s documentation for details and partial workarounds.

Fossil repository files can be read in using the --format=fossil option of the ‘read’ command and written
out with the --format=fossil option of the ‘write’. Ignore patterns are not translated in either
direction.

SVN and CVS are supported for read only, not write. For CVS, reposurgeon must be run from within a
repository directory (that is, a tree of CVS masters; a CVSROOT is not required). When reading from a CVS
top-level directory each module becomes a subdirectory in the reposurgeon representation of the change
history. It is also possible to read a repository from within a CVS module subdirectory and lift that
individual module.

In order to deal with version-control systems that do not have fast-export equivalents, reposurgeon can
also host extractor code that reads repositories directly. For each version-control system supported
through an extractor, reposurgeon uses a small amount of knowledge about the system’s command-line tools
to (in effect) replay repository history into an input stream internally. Repositories under systems
supported through extractors can be read by reposurgeon, but not modified by it. In particular,
reposurgeon can be used to move a repository history from any VCS supported by an extractor to any VCS
supported by a normal importer/exporter pair.

Mercurial repository reading is implemented with an extractor class; writing is handled with
hg-git-fast-import. A test extractor exists for git, but is normally disabled in favor of the regular
exporter.

For details on how to operate reposurgeon, see the Repository Editing and
<http://www.catb.org/esr/reposurgeon/repository-editing.html> Conversion With Reposurgeon" .

REQUIREMENTS

       reposurgeon relies on importers and exporters associated with the VCSes it supports.

       git
           Core git supports both export and import.

       bzr
           Requires bzr plus the bzr-fast-import plugin.

       hg
           Requires core hg and hg-git-fast-import.

       svn
           Stock Subversion commands support export and import.

       darcs
           Stock darcs commands support export.

       CVS
           Requires cvs-fast-export. Note that the quality of CVS lifts may be poor, with individual lifts
           requiring serious hand-hacking. This is due to inherent problems with CVS’s file-oriented model.

       RCS
           Requires cvs-fast-export (yes, that’s not a typo; cvs-fast-export handles RCS collections as well).
           The caveat for CVS applies.

       bk
           Versions 7.3 and after have a fast-export command that reposurgeon can use.

ERROR RETURNS

       Returns 1 if the last command executed threw an error, 0 otherwise.

AUTHOR