According to its developers, "Mercurial is a fast, lightweight Source Control Management system designed for efficient handling of very large distributed projects." Dozens of projects already use the software. Here's how you can get started with some basic version control tasks using Mercurial.
Mercurial is a open distributed version control system. According to Wikipedia, distributed revision control takes a peer-to-peer approach, as opposed to the client-server approach of centralized systems. Rather than a single, central repository with which clients synchronize, each peer's working copy of the codebase is a bona fide repository. Synchronization is conducted by exchanging changesets, which define unique versions of every file, from peer to peer.
Mercurial is good for version control of both personal projects and large-scale enterprise projects.
Installing Mercurial is a breeze. Download the Mercurial tarball, extract the archive, change to the mercurial directory, and run:
$ make
$ sudo make install # do a system-wide install
$ hg debuginstall # sanity check
$ hg # see help
See the software's Web site for detailed installation instructions and platform-specific notes.
To begin exploring Mercurial, you can work with an existing repository or set up your own. To initialize a new local repository with the name "f00-repo," use the command hg init f00-repo. Note that I said "initialize," not "create"; if the directory already exists, hg initializes a new repository there. Otherwise, Mercurial creates a directory named .hg and then initializes it. Mercurial keeps all the metadata about the repository in this directory.
Once you have a repository, you can tell Mercurial about a file you want to track with the command hg add file1.txt. When you're satisfied with the file, check it in with a comment using a command like hg commit -m "Added new file".
You can view a log of your transactions by using the hg log command:
$ hg log
changeset: 0:4706e1104b96
tag: tip
user: amit@ubuntu-laptop
date: Sun Nov 04 22:31:28 2007 +0530
summary: Added new file
Cloning and pulling
If you want to create a working copy of a repository for yourself in which you can create, modify, and commit files before you commit them to the parent repository (so that you can keep working even when you are disconnected from the remote repository, or you just want experiment with the code), you can clone an existing repository, specifying the original and your new repository names:
$ hg clone f00-repo f00-repo-1
2 files updated, 0 files merge d, 0 files removed, 0 files unresolved
Other users can do the same thing, leading to disparate versions of files in diverse repositories on the server or the network. Suppose that John's working copy is f00-repo-1 and Jane's is f00-repo-2. If Jane wants to "pull" in the changes that John committed, she can first determine what things will be pulled with the following command:
$ hg incoming ../f00-repo-1
comparing with ../f00-repo-1
searching for changes
changeset: 3:5b2454e51e13
user: amit@ubuntu-laptop
date: Sun Nov 04 23:43:30 2007 +0530
summary: Added file2
changeset: 4:8503fe7d3247
user: amit@ubuntu-laptop
date: Sun Nov 04 23:44:01 2007 +0530
summary: Added file3
changeset: 5:5a26319e7c66
tag: tip
user: amit@ubuntu-laptop
date: Sun Nov 04 23:48:28 2007 +0530
summary: Added 1 line each
To pull in the changes and update the working copy, she would run:
$ hg pull ../f00-repo-1
pulling from ../f00-repo-1
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 4 changes to 4 files
(run 'hg update' to get a working copy)
$ hg update
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
Pushing
If, once she's made changes, if Jane wants to pass them along to another user, she can push her changes into someone else's repository. Again, the first step is to check what will be pushed:
$ hg outgoing ../f00-repo-3
comparing with ../f00-repo-3
searching for changes
changeset: 3:5b2454e51e13
user: amit@ubuntu-laptop
date: Sun Nov 04 23:43:30 2007 +0530
summary: Added file2
changeset: 4:8503fe7d3247
user: amit@ubuntu-laptop
date: Sun Nov 04 23:44:01 2007 +0530
summary: Added file3
changeset: 5:5a26319e7c66
tag: tip
user: amit@ubuntu-laptop
date: Sun Nov 04 23:48:28 2007 +0530
summary: Added 1 line each
$ hg push ../f00-repo-3
pushing to ../f00-repo-3
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 4 changes to 4 files
If you're concerned about access control, Mercurial has you covered in threeways:
* The Shared SSH method
* The HTTPS method
* The filesystem method
Remote repositories and other version control systems
Our discussions so far, has dealt only with local repositories. With remote repositories, nothing changes except the repository locations. You just have to specify a URL, which could be a remote Web server, an FTP server, or a domain name.
For example, to clone a remote repository, use the command:
$ hg clone http://selenic.com/hg working-rep0
Mercurial offers tools that provide automatic conversion of repositories from other SCMs to Mercurial. ConvertExtension bundled with mercurial supports branches, incremental imports, and only understands CVS, subversion, Darcs and git. This link will be useful for further information on the topic.
Help is never far away. The project has mailing lists and commercial support available. If you need further help, the book Distributed Revision Control with Mercurial is an excellent resource to have. The Mercurial Web site also lists some HOWTOs.
Conclusion
Mercurial is easy to set up, fast, and lightweight -- as good for your local version control needs as it is for maintaining large projects. Even going public with your repository is not a big hassle -- free Mercurial hosting is available.
6:["$","$4",null,{"fallback":[[["$","link","css:/assets/_layout-BzYdn0f6.css",{"rel":"stylesheet","precedence":"vite-rsc/importer-resources","href":"/assets/_layout-BzYdn0f6.css","data-rsc-css-href":"/assets/_layout-BzYdn0f6.css"}],"$undefined"],["$","div",null,{"className":"flex justify-center items-center p-8","children":["$","div",null,{"className":"animate-spin rounded-full h-8 w-8 border-b-2 border-indigo-600"}]}]],"children":["$","div",null,{"className":"bg-white/95 mt-0.5 py-6 sm:py-12","children":["$","article",null,{"className":"mx-auto w-full max-w-2xl format format-sm sm:format-base lg:format-lg format-blue dark:format-invert","children":[["$","header",null,{"className":"mb-4 lg:mb-6 not-format","children":[["$","h1",null,{"className":"mb-4 text-3xl font-extrabold leading-tight text-gray-900 lg:mb-6 lg:text-4xl dark:text-white","children":"Introducing Mercurial, a distributed version control system"}],["$","address",null,{"className":"flex items-center mb-6 not-italic","children":["$","div",null,{"className":"inline-flex items-center text-sm text-gray-900 dark:text-white","children":[["$","img",null,{"className":"mr-3 w-8 h-8 rounded-full","src":"$8","alt":"Golagana Gowri Prasad"}],["$","a",null,{"href":"/author/golagana_gowri_prasad_73326215","rel":"author","className":"font-bold capitalize hover:underline dark:text-white","children":"Golagana Gowri Prasad"}],["$","span",null,{"className":"mx-1 text-md text-gray-400 dark:text-gray-500","children":"·"}],["$","span",null,{"className":"inline-flex items-center ml-1 text-gray-500 dark:text-gray-400","children":"5 min read"}],["$","span",null,{"className":"mx-1 text-md text-gray-400 dark:text-gray-500","children":"·"}],["$","time",null,{"dateTime":"Fri Jan 25 2008","className":"text-gray-500 dark:text-gray-400","children":"Jan 25, 2008"}],[["$","span",null,{"className":"mx-1 text-md text-gray-400 dark:text-gray-500","children":"·"}],["$","a","it-and-systems",{"href":"/t/it-and-systems","className":"capitalize text-sm text-gray-500 dark:text-gray-400 hover:text-gray-600","children":"it & systems"}]]]}]}]]}],["$","div",null,{"className":"lead prose mt-4 text-lg leading-8 text-gray-600","children":["$","div",null,{"dangerouslySetInnerHTML":{"__html":"$9"}}]}],"$La","$Lb"]}]}]}] c:T63b,M12.315 2c2.43 0 2.784.013 3.808.06 1.064.049 1.791.218 2.427.465a4.902 4.902 0 011.772 1.153 4.902 4.902 0 011.153 1.772c.247.636.416 1.363.465 2.427.048 1.067.06 1.407.06 4.123v.08c0 2.643-.012 2.987-.06 4.043-.049 1.064-.218 1.791-.465 2.427a4.902 4.902 0 01-1.153 1.772 4.902 4.902 0 01-1.772 1.153c-.636.247-1.363.416-2.427.465-1.067.048-1.407.06-4.123.06h-.08c-2.643 0-2.987-.012-4.043-.06-1.064-.049-1.791-.218-2.427-.465a4.902 4.902 0 01-1.772-1.153 4.902 4.902 0 01-1.153-1.772c-.247-.636-.416-1.363-.465-2.427-.047-1.024-.06-1.379-.06-3.808v-.63c0-2.43.013-2.784.06-3.808.049-1.064.218-1.791.465-2.427a4.902 4.902 0 011.153-1.772A4.902 4.902 0 015.45 2.525c.636-.247 1.363-.416 2.427-.465C8.901 2.013 9.256 2 11.685 2h.63zm-.081 1.802h-.468c-2.456 0-2.784.011-3.807.058-.975.045-1.504.207-1.857.344-.467.182-.8.398-1.15.748-.35.35-.566.683-.748 1.15-.137.353-.3.882-.344 1.857-.047 1.023-.058 1.351-.058 3.807v.468c0 2.456.011 2.784.058 3.807.045.975.207 1.504.344 1.857.182.466.399.8.748 1.15.35.35.683.566 1.15.748.353.137.882.3 1.857.344 1.054.048 1.37.058 4.041.058h.08c2.597 0 2.917-.01 3.96-.058.976-.045 1.505-.207 1.858-.344.466-.182.8-.398 1.15-.748.35-.35.566-.683.748-1.15.137-.353.3-.882.344-1.857.048-1.055.058-1.37.058-4.041v-.08c0-2.597-.01-2.917-.058-3.96-.045-.976-.207-1.505-.344-1.858a3.097 3.097 0 00-.748-1.15 3.098 3.098 0 00-1.15-.748c-.353-.137-.882-.3-1.857-.344-1.023-.047-1.351-.058-3.807-.058zM12 6.865a5.135 5.135 0 110 10.27 5.135 5.135 0 010-10.27zm0 1.802a3.333 3.333 0 100 6.666 3.333 3.333 0 000-6.666zm5.338-3.205a1.2 1.2 0 110 2.4 1.2 1.2 0 010-2.4z7:["$","footer",null,{"className":"bg-gray-900 dark:bg-gray-900","children":["$","div",null,{"className":"mx-auto max-w-7xl px-6 py-4.5 md:flex md:items-center md:justify-between lg:px-8","children":[["$","div",null,{"className":"flex justify-center space-x-6 md:order-2","children":[["$","a","Facebook",{"href":"https://facebook.com/gleeztech","target":"_blank","rel":"noopener noreferrer","className":"text-gray-400 hover:text-gray-500","children":[["$","span",null,{"className":"sr-only","children":"Facebook"}],["$","svg",null,{"className":"h-6 w-6","fill":"currentColor","viewBox":"0 0 24 24","aria-hidden":"true","children":["$","path",null,{"fillRule":"evenodd","d":"M22 12c0-5.523-4.477-10-10-10S2 6.477 2 12c0 4.991 3.657 9.128 8.438 9.878v-6.987h-2.54V12h2.54V9.797c0-2.506 1.492-3.89 3.777-3.89 1.094 0 2.238.195 2.238.195v2.46h-1.26c-1.243 0-1.63.771-1.63 1.562V12h2.773l-.443 2.89h-2.33v6.988C18.343 21.128 22 16.991 22 12z","clipRule":"evenodd"}]}]]}],["$","a","Instagram",{"href":"https://instagram.com/gleeztech","target":"_blank","rel":"noopener noreferrer","className":"text-gray-400 hover:text-gray-500","children":[["$","span",null,{"className":"sr-only","children":"Instagram"}],["$","svg",null,{"className":"h-6 w-6","fill":"currentColor","viewBox":"0 0 24 24","aria-hidden":"true","children":["$","path",null,{"fillRule":"evenodd","d":"$c","clipRule":"evenodd"}]}]]}],["$","a","X",{"href":"https://x.com/gleeztech","target":"_blank","rel":"noopener noreferrer","className":"text-gray-400 hover:text-gray-500","children":[["$","span",null,{"className":"sr-only","children":"X"}],["$","svg",null,{"className":"h-6 w-6","fill":"currentColor","viewBox":"0 0 24 24","aria-hidden":"true","children":["$","path",null,{"d":"M13.6823 10.6218L20.2391 3H18.6854L12.9921 9.61788L8.44486 3H3.2002L10.0765 13.0074L3.2002 21H4.75404L10.7663 14.0113L15.5685 21H20.8131L13.6819 10.6218H13.6823ZM11.5541 13.0956L10.8574 12.0991L5.31391 4.16971H7.70053L12.1742 10.5689L12.8709 11.5655L18.6861 19.8835H16.2995L11.5541 13.096V13.0956Z"}]}]]}],"$Ld"]}],"$Le"]}]}] a:null b:["$","$4",null,{"fallback":["$","div",null,{"className":"comments-skeleton","children":[["$","div",null,{"className":"h-6 bg-gray-200 rounded w-32 mb-4 animate-pulse"}],["$","div",null,{"className":"space-y-3","children":[["$","div","1",{"className":"h-16 bg-gray-100 rounded animate-pulse"}],["$","div","2",{"className":"h-16 bg-gray-100 rounded animate-pulse"}],["$","div","3",{"className":"h-16 bg-gray-100 rounded animate-pulse"}]]}]]}],"children":"$Lf"}] d:["$","a","GitHub",{"href":"https://github.com/gleez","target":"_blank","rel":"noopener noreferrer","className":"text-gray-400 hover:text-gray-500","children":[["$","span",null,{"className":"sr-only","children":"GitHub"}],["$","svg",null,{"className":"h-6 w-6","fill":"currentColor","viewBox":"0 0 24 24","aria-hidden":"true","children":["$","path",null,{"fillRule":"evenodd","d":"M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-1.988 1.029-2.688-.103-.253-.446-1.272.098-2.65 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.379.202 2.398.1 2.651.64.7 1.028 1.595 1.028 2.688 0 3.848-2.339 4.695-4.566 4.943.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z","clipRule":"evenodd"}]}]]}] e:["$","div",null,{"className":"mt-8 md:order-1 md:mt-0","children":["$","p",null,{"className":"text-sm leading-5 text-gray-400","children":["© 2005 - ",2026," Gleez Inc. All rights reserved."]}]}] f:["$","div",null,{"className":"mt-8","children":[["$","h3",null,{"className":"text-xl font-semibold mb-4","children":"Voices"}],["$","p",null,{"className":"text-gray-500","children":"Be the first to add your voice to \"Introducing Mercurial, a distributed version control system\"!"}]]}]