69 lines
3.9 KiB
Markdown
69 lines
3.9 KiB
Markdown
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# Migrating from CVS
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[CVS](https://savannah.nongnu.org/projects/cvs) is an old centralized version
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control system similar to [SVN](svn.md).
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## CVS vs Git
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The following list illustrates the main differences between CVS and Git:
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- **Git is distributed.** On the other hand, CVS is centralized using a client-server
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architecture. This translates to Git having a more flexible workflow since
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your working area is a copy of the entire repository. This decreases the
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overhead when switching branches or merging for example, since you don't have
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to communicate with a remote server.
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- **Atomic operations.** In Git all operations are
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[atomic](https://en.wikipedia.org/wiki/Atomic_commit), either they succeed as
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whole, or they fail without any changes. In CVS, commits (and other operations)
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are not atomic. If an operation on the repository is interrupted in the middle,
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the repository can be left in an inconsistent state.
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- **Storage method.** Changes in CVS are per file (changeset), while in Git
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a committed file(s) is stored in its entirety (snapshot). That means that's
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very easy in Git to revert or undo a whole change.
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- **Revision IDs.** The fact that in CVS changes are per files, the revision ID
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is depicted by version numbers, for example `1.4` reflects how many time a
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given file has been changed. In Git, each version of a project as a whole
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(each commit) has its unique name given by SHA-1.
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- **Merge tracking.** Git uses a commit-before-merge approach rather than
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merge-before-commit (or update-then-commit) like CVS. If while you were
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preparing to create a new commit (new revision) somebody created a
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new commit on the same branch and pushed to the central repository, CVS would
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force you to first update your working directory and resolve conflicts before
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allowing you to commit. This is not the case with Git. You first commit, save
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your state in version control, then you merge the other developer's changes.
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You can also ask the other developer to do the merge and resolve any conflicts
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themselves.
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- **Signed commits.** Git supports signing your commits with GPG for additional
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security and verification that the commit indeed came from its original author.
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GitLab can [integrate with GPG](../repository/gpg_signed_commits/index.md)
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and show whether a signed commit is correctly verified.
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_Some of the items above were taken from this great
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[Stack Overflow post](https://stackoverflow.com/a/824241/974710). For a more
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complete list of differences, consult the
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Wikipedia article on [comparing the different version control software](https://en.wikipedia.org/wiki/Comparison_of_version_control_software)._
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## Why migrate
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CVS is old with no new release since 2008. Git provides more tools to work
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with (`git bisect` for one) which makes for a more productive workflow.
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Migrating to Git/GitLab there is:
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- **Shorter learning curve**, Git has a big community and a vast number of
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tutorials to get you started (see our [Git topic](../../../topics/git/index.md)).
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- **Integration with modern tools**, migrating to Git and GitLab you can have
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an open source end-to-end software development platform with built-in version
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control, issue tracking, code review, CI/CD, and more.
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- **Support for many network protocols**. Git supports SSH, HTTP/HTTPS and rsync
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among others, whereas CVS supports only SSH and its own insecure pserver
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protocol with no user authentication.
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## How to migrate
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Here's a few links to get you started with the migration:
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- [Migrate using the `cvs-fast-export` tool](http://www.catb.org/~esr/reposurgeon/dvcs-migration-guide.html) ([_source code_](https://gitlab.com/esr/cvs-fast-export))
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- [Stack Overflow post on importing the CVS repo](https://stackoverflow.com/a/11490134/974710)
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- [Convert a CVS repository to Git](http://www.techrepublic.com/blog/linux-and-open-source/convert-cvs-repositories-to-git/)
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- [Man page of the `git-cvsimport` tool](https://www.kernel.org/pub/software/scm/git/docs/git-cvsimport.html)
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