Git - Plumbing and Porcelain

<!DOCTYPE html> <html lang="en"> <head> <meta charset='utf-8'> <meta content='IE=edge,chrome=1' http-equiv='X-UA-Compatible'> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Git - Plumbing and Porcelain</title> <link href="/favicon.ico" rel='shortcut icon' type='image/x-icon'> <link rel="stylesheet" href="/application.min.css"> <script src="/js/modernizr.js"></script> <script src="/js/modernize.js"></script> </head> <body id="documentation"> <div class="inner"> <header> <a href="/"><img src="/images/logo@2x.png" width="110" height="46" alt="Git" /></a> <span id="tagline"></span> <script type="text/javascript"> const taglines = [ "fast-version-control", "everything-is-local", "distributed-even-if-your-workflow-isnt", "local-branching-on-the-cheap", "distributed-is-the-new-centralized" ]; var tagline = taglines[Math.floor(Math.random() * taglines.length)]; document.getElementById('tagline').innerHTML = '--' + tagline; </script> <form id="search" 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Full translation available in <table> <tr><td><a href="/book/az/v2/Git%e2%80%99in-Daxili-%c4%b0%c5%9fl%c9%99ri-Plumbing-v%c9%99-Porcelain">azərbaycan dili</a>,</td></tr> <tr><td><a href="/book/bg/v2/%d0%9f%d1%80%d0%b8%d0%bb%d0%be%d0%b6%d0%b5%d0%bd%d0%b8%d0%b5-B:-%d0%92%d0%b3%d1%80%d0%b0%d0%b6%d0%b4%d0%b0%d0%bd%d0%b5-%d0%bd%d0%b0-Git-%d0%b2-%d0%bf%d1%80%d0%b8%d0%bb%d0%be%d0%b6%d0%b5%d0%bd%d0%b8%d1%8f-Git-%d0%be%d1%82-%d0%ba%d0%be%d0%bc%d0%b0%d0%bd%d0%b4%d0%b5%d0%bd-%d1%80%d0%b5%d0%b4">български език</a>,</td></tr> <tr><td><a href="/book/de/v2/Git-Interna-Basisbefehle-und-Standardbefehle-Plumbing-and-Porcelain">Deutsch</a>,</td></tr> <tr><td><a href="/book/es/v2/Los-entresijos-internos-de-Git-Fontaner%c3%ada-y-porcelana">Español</a>,</td></tr> <tr><td><a href="/book/fr/v2/Les-tripes-de-Git-Plomberie-et-porcelaine">Français</a>,</td></tr> <tr><td><a href="/book/gr">Ελληνικά</a>,</td></tr> <tr><td><a href="/book/ja/v2/Git%e3%81%ae%e5%86%85%e5%81%b4-%e9%85%8d%e7%ae%a1%ef%bc%88Plumbing%ef%bc%89%e3%81%a8%e7%a3%81%e5%99%a8%ef%bc%88Porcelain%ef%bc%89">日本語</a>,</td></tr> <tr><td><a href="/book/ko/v2/Git%ec%9d%98-%eb%82%b4%eb%b6%80-Plumbing-%eb%aa%85%eb%a0%b9%ea%b3%bc-Porcelain-%eb%aa%85%eb%a0%b9">한국어</a>,</td></tr> <tr><td><a href="/book/nl/v2/Git-Binnenwerk-Binnenwerk-en-koetswerk-plumbing-and-porcelain">Nederlands</a>,</td></tr> <tr><td><a href="/book/ru/v2/Git-%d0%b8%d0%b7%d0%bd%d1%83%d1%82%d1%80%d0%b8-%d0%a1%d0%b0%d0%bd%d1%82%d0%b5%d1%85%d0%bd%d0%b8%d0%ba%d0%b0-%d0%b8-%d0%a4%d0%b0%d1%80%d1%84%d0%be%d1%80">Русский</a>,</td></tr> <tr><td><a href="/book/sl/v2/Notranjost-Gita-Napeljava-in-keramika">Slovenščina</a>,</td></tr> <tr><td><a href="/book/tl/v2/Mga-Panloob-ng-GIT-Plumbing-and-Porcelain">Tagalog</a>,</td></tr> <tr><td><a href="/book/uk/v2/Git-%d0%b7%d1%81%d0%b5%d1%80%d0%b5%d0%b4%d0%b8%d0%bd%d0%b8-%d0%9a%d1%83%d1%85%d0%be%d0%bd%d0%bd%d1%96-%d1%82%d0%b0-%d0%bf%d0%b0%d1%80%d0%b0%d0%b4%d0%bd%d1%96-%d0%ba%d0%be%d0%bc%d0%b0%d0%bd%d0%b4%d0%b8">Українська</a></td></tr> <tr><td><a href="/book/zh/v2/Git-%e5%86%85%e9%83%a8%e5%8e%9f%e7%90%86-%e5%ba%95%e5%b1%82%e5%91%bd%e4%bb%a4%e4%b8%8e%e4%b8%8a%e5%b1%82%e5%91%bd%e4%bb%a4">简体中文</a>,</td></tr> </table> </p> <p> Partial translations available in <table> <tr><td><a href="/book/cs/v2/Git-Internals-Plumbing-and-Porcelain">Čeština</a>,</td></tr> <tr><td><a href="/book/mk/v2/%d0%92%d0%bd%d0%b0%d1%82%d1%80%d0%b5%d1%88%d0%bd%d0%be%d1%81%d1%82%d0%b0-%d0%bd%d0%b0-Git-Plumbing-and-Porcelain">Македонски</a>,</td></tr> <tr><td><a href="/book/pl/v2/Mechanizmy-wewn%c4%99trzne-w-Git-Komendy-typu-plumbing-i-porcelain">Polski</a>,</td></tr> <tr><td><a href="/book/sr/v2/%d0%93%d0%b8%d1%82-%d0%b8%d0%b7%d0%bd%d1%83%d1%82%d1%80%d0%b0-%d0%92%d0%be%d0%b4%d0%be%d0%b2%d0%be%d0%b4-%d0%b8-%d0%bf%d0%be%d1%80%d1%86%d0%b5%d0%bb%d0%b0%d0%bd">Српски</a>,</td></tr> <tr><td><a href="/book/uz/v2/Git-Internals-Plumbing-and-Porcelain">Ўзбекча</a>,</td></tr> <tr><td><a href="/book/zh-tw/v2/Git-Internals-Plumbing-and-Porcelain">繁體中文</a>,</td></tr> </table> </p> <p> Translations started for <table> <tr><td><a href="/book/be/v2/Git-Internals-Plumbing-and-Porcelain">Беларуская</a>,</td></tr> <tr><td><a href="/book/fa/v2/Git-Internals-Plumbing-and-Porcelain" dir="rtl">فارسی</a>,</td></tr> <tr><td><a href="/book/id/v2/Git-Internals-Plumbing-and-Porcelain">Indonesian</a>,</td></tr> <tr><td><a href="/book/it/v2/Git-Internals-Plumbing-and-Porcelain">Italiano</a>,</td></tr> <tr><td><a href="/book/ms/v2/Git-Internals-Plumbing-and-Porcelain">Bahasa Melayu</a>,</td></tr> <tr><td><a href="/book/pt-br/v2/Funcionamento-Interno-do-Git-Encanamento-e-Porcelana">Português (Brasil)</a>,</td></tr> <tr><td><a href="/book/pt-pt/v2/Internos-do-Git-Plumbing-and-Porcelain">Português (Portugal)</a>,</td></tr> <tr><td><a href="/book/sv/v2/Git-Internals-Plumbing-and-Porcelain">Svenska</a>,</td></tr> <tr><td><a href="/book/tr/v2/Dahili-Git-%c3%96geleri-Tesisat-ve-D%c3%b6%c5%9feme-Plumbing-ve-Porcelain">Türkçe</a>.</td></tr> </table> </p> <hr class="sidebar"/> <p> The source of this book is <a href="https://github.com/progit/progit2">hosted on GitHub.</a></br> Patches, suggestions and comments are welcome. </p> </nav> </aside> <div id="content"> <div id="book-chapters"> <a class="dropdown-trigger" id="book-chapters-trigger" data-panel-id="chapters-dropdown" href="#">Chapters ▾</a> <div class='dropdown-panel' id='chapters-dropdown'> <div class='three-column'> <div class="column-left"> <ol class='book-toc'> <li class='chapter'> <h2>1. <a href="/book/en/v2/Getting-Started-About-Version-Control">Getting Started</a></h2> <ol> <li> 1.1 <a href="/book/en/v2/Getting-Started-About-Version-Control">About Version Control</a> </li> <li> 1.2 <a href="/book/en/v2/Getting-Started-A-Short-History-of-Git">A Short History of Git</a> </li> <li> 1.3 <a href="/book/en/v2/Getting-Started-What-is-Git%3F">What is Git?</a> </li> <li> 1.4 <a href="/book/en/v2/Getting-Started-The-Command-Line">The Command Line</a> </li> <li> 1.5 <a href="/book/en/v2/Getting-Started-Installing-Git">Installing Git</a> </li> <li> 1.6 <a href="/book/en/v2/Getting-Started-First-Time-Git-Setup">First-Time Git Setup</a> </li> <li> 1.7 <a href="/book/en/v2/Getting-Started-Getting-Help">Getting Help</a> </li> <li> 1.8 <a href="/book/en/v2/Getting-Started-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>2. <a href="/book/en/v2/Git-Basics-Getting-a-Git-Repository">Git Basics</a></h2> <ol> <li> 2.1 <a href="/book/en/v2/Git-Basics-Getting-a-Git-Repository">Getting a Git Repository</a> </li> <li> 2.2 <a href="/book/en/v2/Git-Basics-Recording-Changes-to-the-Repository">Recording Changes to the Repository</a> </li> <li> 2.3 <a href="/book/en/v2/Git-Basics-Viewing-the-Commit-History">Viewing the Commit History</a> </li> <li> 2.4 <a href="/book/en/v2/Git-Basics-Undoing-Things">Undoing Things</a> </li> <li> 2.5 <a href="/book/en/v2/Git-Basics-Working-with-Remotes">Working with Remotes</a> </li> <li> 2.6 <a href="/book/en/v2/Git-Basics-Tagging">Tagging</a> </li> <li> 2.7 <a href="/book/en/v2/Git-Basics-Git-Aliases">Git Aliases</a> </li> <li> 2.8 <a href="/book/en/v2/Git-Basics-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>3. <a href="/book/en/v2/Git-Branching-Branches-in-a-Nutshell">Git Branching</a></h2> <ol> <li> 3.1 <a href="/book/en/v2/Git-Branching-Branches-in-a-Nutshell">Branches in a Nutshell</a> </li> <li> 3.2 <a href="/book/en/v2/Git-Branching-Basic-Branching-and-Merging">Basic Branching and Merging</a> </li> <li> 3.3 <a href="/book/en/v2/Git-Branching-Branch-Management">Branch Management</a> </li> <li> 3.4 <a href="/book/en/v2/Git-Branching-Branching-Workflows">Branching Workflows</a> </li> <li> 3.5 <a href="/book/en/v2/Git-Branching-Remote-Branches">Remote Branches</a> </li> <li> 3.6 <a href="/book/en/v2/Git-Branching-Rebasing">Rebasing</a> </li> <li> 3.7 <a href="/book/en/v2/Git-Branching-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>4. <a href="/book/en/v2/Git-on-the-Server-The-Protocols">Git on the Server</a></h2> <ol> <li> 4.1 <a href="/book/en/v2/Git-on-the-Server-The-Protocols">The Protocols</a> </li> <li> 4.2 <a href="/book/en/v2/Git-on-the-Server-Getting-Git-on-a-Server">Getting Git on a Server</a> </li> <li> 4.3 <a href="/book/en/v2/Git-on-the-Server-Generating-Your-SSH-Public-Key">Generating Your SSH Public Key</a> </li> <li> 4.4 <a href="/book/en/v2/Git-on-the-Server-Setting-Up-the-Server">Setting Up the Server</a> </li> <li> 4.5 <a href="/book/en/v2/Git-on-the-Server-Git-Daemon">Git Daemon</a> </li> <li> 4.6 <a href="/book/en/v2/Git-on-the-Server-Smart-HTTP">Smart HTTP</a> </li> <li> 4.7 <a href="/book/en/v2/Git-on-the-Server-GitWeb">GitWeb</a> </li> <li> 4.8 <a href="/book/en/v2/Git-on-the-Server-GitLab">GitLab</a> </li> <li> 4.9 <a href="/book/en/v2/Git-on-the-Server-Third-Party-Hosted-Options">Third Party Hosted Options</a> </li> <li> 4.10 <a href="/book/en/v2/Git-on-the-Server-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>5. <a href="/book/en/v2/Distributed-Git-Distributed-Workflows">Distributed Git</a></h2> <ol> <li> 5.1 <a href="/book/en/v2/Distributed-Git-Distributed-Workflows">Distributed Workflows</a> </li> <li> 5.2 <a href="/book/en/v2/Distributed-Git-Contributing-to-a-Project">Contributing to a Project</a> </li> <li> 5.3 <a href="/book/en/v2/Distributed-Git-Maintaining-a-Project">Maintaining a Project</a> </li> <li> 5.4 <a href="/book/en/v2/Distributed-Git-Summary">Summary</a> </li> </ol> </li> </ol> </div> <div class='column-middle'> <ol class='book-toc'> <li class='chapter'> <h2>6. <a href="/book/en/v2/GitHub-Account-Setup-and-Configuration">GitHub</a></h2> <ol> <li> 6.1 <a href="/book/en/v2/GitHub-Account-Setup-and-Configuration">Account Setup and Configuration</a> </li> <li> 6.2 <a href="/book/en/v2/GitHub-Contributing-to-a-Project">Contributing to a Project</a> </li> <li> 6.3 <a href="/book/en/v2/GitHub-Maintaining-a-Project">Maintaining a Project</a> </li> <li> 6.4 <a href="/book/en/v2/GitHub-Managing-an-organization">Managing an organization</a> </li> <li> 6.5 <a href="/book/en/v2/GitHub-Scripting-GitHub">Scripting GitHub</a> </li> <li> 6.6 <a href="/book/en/v2/GitHub-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>7. <a href="/book/en/v2/Git-Tools-Revision-Selection">Git Tools</a></h2> <ol> <li> 7.1 <a href="/book/en/v2/Git-Tools-Revision-Selection">Revision Selection</a> </li> <li> 7.2 <a href="/book/en/v2/Git-Tools-Interactive-Staging">Interactive Staging</a> </li> <li> 7.3 <a href="/book/en/v2/Git-Tools-Stashing-and-Cleaning">Stashing and Cleaning</a> </li> <li> 7.4 <a href="/book/en/v2/Git-Tools-Signing-Your-Work">Signing Your Work</a> </li> <li> 7.5 <a href="/book/en/v2/Git-Tools-Searching">Searching</a> </li> <li> 7.6 <a href="/book/en/v2/Git-Tools-Rewriting-History">Rewriting History</a> </li> <li> 7.7 <a href="/book/en/v2/Git-Tools-Reset-Demystified">Reset Demystified</a> </li> <li> 7.8 <a href="/book/en/v2/Git-Tools-Advanced-Merging">Advanced Merging</a> </li> <li> 7.9 <a href="/book/en/v2/Git-Tools-Rerere">Rerere</a> </li> <li> 7.10 <a href="/book/en/v2/Git-Tools-Debugging-with-Git">Debugging with Git</a> </li> <li> 7.11 <a href="/book/en/v2/Git-Tools-Submodules">Submodules</a> </li> <li> 7.12 <a href="/book/en/v2/Git-Tools-Bundling">Bundling</a> </li> <li> 7.13 <a href="/book/en/v2/Git-Tools-Replace">Replace</a> </li> <li> 7.14 <a href="/book/en/v2/Git-Tools-Credential-Storage">Credential Storage</a> </li> <li> 7.15 <a href="/book/en/v2/Git-Tools-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>8. <a href="/book/en/v2/Customizing-Git-Git-Configuration">Customizing Git</a></h2> <ol> <li> 8.1 <a href="/book/en/v2/Customizing-Git-Git-Configuration">Git Configuration</a> </li> <li> 8.2 <a href="/book/en/v2/Customizing-Git-Git-Attributes">Git Attributes</a> </li> <li> 8.3 <a href="/book/en/v2/Customizing-Git-Git-Hooks">Git Hooks</a> </li> <li> 8.4 <a href="/book/en/v2/Customizing-Git-An-Example-Git-Enforced-Policy">An Example Git-Enforced Policy</a> </li> <li> 8.5 <a href="/book/en/v2/Customizing-Git-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>9. <a href="/book/en/v2/Git-and-Other-Systems-Git-as-a-Client">Git and Other Systems</a></h2> <ol> <li> 9.1 <a href="/book/en/v2/Git-and-Other-Systems-Git-as-a-Client">Git as a Client</a> </li> <li> 9.2 <a href="/book/en/v2/Git-and-Other-Systems-Migrating-to-Git">Migrating to Git</a> </li> <li> 9.3 <a href="/book/en/v2/Git-and-Other-Systems-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>10. <a href="/book/en/v2/Git-Internals-Plumbing-and-Porcelain">Git Internals</a></h2> <ol> <li> 10.1 <a href="/book/en/v2/Git-Internals-Plumbing-and-Porcelain" class="active">Plumbing and Porcelain</a> </li> <li> 10.2 <a href="/book/en/v2/Git-Internals-Git-Objects">Git Objects</a> </li> <li> 10.3 <a href="/book/en/v2/Git-Internals-Git-References">Git References</a> </li> <li> 10.4 <a href="/book/en/v2/Git-Internals-Packfiles">Packfiles</a> </li> <li> 10.5 <a href="/book/en/v2/Git-Internals-The-Refspec">The Refspec</a> </li> <li> 10.6 <a href="/book/en/v2/Git-Internals-Transfer-Protocols">Transfer Protocols</a> </li> <li> 10.7 <a href="/book/en/v2/Git-Internals-Maintenance-and-Data-Recovery">Maintenance and Data Recovery</a> </li> <li> 10.8 <a href="/book/en/v2/Git-Internals-Environment-Variables">Environment Variables</a> </li> <li> 10.9 <a href="/book/en/v2/Git-Internals-Summary">Summary</a> </li> </ol> </li> </ol> </div> <div class='column-right'> <ol class='book-toc'> <li class='chapter'> <h2>A1. <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Graphical-Interfaces">Appendix A: Git in Other Environments</a></h2> <ol> <li> A1.1 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Graphical-Interfaces">Graphical Interfaces</a> </li> <li> A1.2 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Visual-Studio">Git in Visual Studio</a> </li> <li> A1.3 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Visual-Studio-Code">Git in Visual Studio Code</a> </li> <li> A1.4 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-IntelliJ-/-PyCharm-/-WebStorm-/-PhpStorm-/-RubyMine">Git in IntelliJ / PyCharm / WebStorm / PhpStorm / RubyMine</a> </li> <li> A1.5 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Sublime-Text">Git in Sublime Text</a> </li> <li> A1.6 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Bash">Git in Bash</a> </li> <li> A1.7 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Zsh">Git in Zsh</a> </li> <li> A1.8 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Git-in-PowerShell">Git in PowerShell</a> </li> <li> A1.9 <a href="/book/en/v2/Appendix-A:-Git-in-Other-Environments-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>A2. <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-Command-line-Git">Appendix B: Embedding Git in your Applications</a></h2> <ol> <li> A2.1 <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-Command-line-Git">Command-line Git</a> </li> <li> A2.2 <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-Libgit2">Libgit2</a> </li> <li> A2.3 <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-JGit">JGit</a> </li> <li> A2.4 <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-go-git">go-git</a> </li> <li> A2.5 <a href="/book/en/v2/Appendix-B:-Embedding-Git-in-your-Applications-Dulwich">Dulwich</a> </li> </ol> </li> <li class='chapter'> <h2>A3. <a href="/book/en/v2/Appendix-C:-Git-Commands-Setup-and-Config">Appendix C: Git Commands</a></h2> <ol> <li> A3.1 <a href="/book/en/v2/Appendix-C:-Git-Commands-Setup-and-Config">Setup and Config</a> </li> <li> A3.2 <a href="/book/en/v2/Appendix-C:-Git-Commands-Getting-and-Creating-Projects">Getting and Creating Projects</a> </li> <li> A3.3 <a href="/book/en/v2/Appendix-C:-Git-Commands-Basic-Snapshotting">Basic Snapshotting</a> </li> <li> A3.4 <a href="/book/en/v2/Appendix-C:-Git-Commands-Branching-and-Merging">Branching and Merging</a> </li> <li> A3.5 <a href="/book/en/v2/Appendix-C:-Git-Commands-Sharing-and-Updating-Projects">Sharing and Updating Projects</a> </li> <li> A3.6 <a href="/book/en/v2/Appendix-C:-Git-Commands-Inspection-and-Comparison">Inspection and Comparison</a> </li> <li> A3.7 <a href="/book/en/v2/Appendix-C:-Git-Commands-Debugging">Debugging</a> </li> <li> A3.8 <a href="/book/en/v2/Appendix-C:-Git-Commands-Patching">Patching</a> </li> <li> A3.9 <a href="/book/en/v2/Appendix-C:-Git-Commands-Email">Email</a> </li> <li> A3.10 <a href="/book/en/v2/Appendix-C:-Git-Commands-External-Systems">External Systems</a> </li> <li> A3.11 <a href="/book/en/v2/Appendix-C:-Git-Commands-Administration">Administration</a> </li> <li> A3.12 <a href="/book/en/v2/Appendix-C:-Git-Commands-Plumbing-Commands">Plumbing Commands</a> </li> </ol> </li> </ol> </div> </div> </div> <span class="light" id="edition"> 2nd Edition </span> </div> <div id="main" data-pagefind-filter="category:book" data-pagefind-meta="category:Book" data-pagefind-weight="0.05" data-pagefind-body class="book edition2"> <h1>10.1 Git Internals - Plumbing and Porcelain</h1> <div> <p>You may have skipped to this chapter from a much earlier chapter, or you may have gotten here after sequentially reading the entire book up to this point — in either case, this is where we’ll go over the inner workings and implementation of Git. We found that understanding this information was fundamentally important to appreciating how useful and powerful Git is, but others have argued to us that it can be confusing and unnecessarily complex for beginners. Thus, we’ve made this discussion the last chapter in the book so you could read it early or later in your learning process. We leave it up to you to decide.</p><p>Now that you’re here, let’s get started. First, if it isn’t yet clear, Git is fundamentally a content-addressable filesystem with a VCS user interface written on top of it. You’ll learn more about what this means in a bit.</p><p>In the early days of Git (mostly pre 1.5), the user interface was much more complex because it emphasized this filesystem rather than a polished VCS. In the last few years, the UI has been refined until it’s as clean and easy to use as any system out there; however, the stereotype lingers about the early Git UI that was complex and difficult to learn.</p><p>The content-addressable filesystem layer is amazingly cool, so we’ll cover that first in this chapter; then, you’ll learn about the transport mechanisms and the repository maintenance tasks that you may eventually have to deal with.</p> <h2 id="_plumbing_porcelain">Plumbing and Porcelain</h2> <div class="paragraph"> <p>This book covers primarily how to use Git with 30 or so subcommands such as <code>checkout</code>, <code>branch</code>, <code>remote</code>, and so on. But because Git was initially a toolkit for a version control system rather than a full user-friendly VCS, it has a number of subcommands that do low-level work and were designed to be chained together UNIX-style or called from scripts. These commands are generally referred to as Git’s “plumbing” commands, while the more user-friendly commands are called “porcelain” commands.</p> </div> <div class="paragraph"> <p>As you will have noticed by now, this book’s first nine chapters deal almost exclusively with porcelain commands. But in this chapter, you’ll be dealing mostly with the lower-level plumbing commands, because they give you access to the inner workings of Git, and help demonstrate how and why Git does what it does. Many of these commands aren’t meant to be used manually on the command line, but rather to be used as building blocks for new tools and custom scripts.</p> </div> <div class="paragraph"> <p>When you run <code>git init</code> in a new or existing directory, Git creates the <code>.git</code> directory, which is where almost everything that Git stores and manipulates is located. If you want to back up or clone your repository, copying this single directory elsewhere gives you nearly everything you need. This entire chapter basically deals with what you can see in this directory. Here’s what a newly-initialized <code>.git</code> directory typically looks like:</p> </div> <div class="listingblock"> <div class="content"> <pre class="highlight"><code class="language-console" data-lang="console">$ ls -F1 config description HEAD hooks/ info/ objects/ refs/</code></pre> </div> </div> <div class="paragraph"> <p>Depending on your version of Git, you may see some additional content there, but this is a fresh <code>git init</code> repository — it’s what you see by default. The <code>description</code> file is used only by the GitWeb program, so don’t worry about it. The <code>config</code> file contains your project-specific configuration options, and the <code>info</code> directory keeps a global exclude file for ignored patterns that you don’t want to track in a <code>.gitignore</code> file. The <code>hooks</code> directory contains your client- or server-side hook scripts, which are discussed in detail in <a href="/book/en/v2/ch00/_git_hooks">Git Hooks</a>.</p> </div> <div class="paragraph"> <p>This leaves four important entries: the <code>HEAD</code> and (yet to be created) <code>index</code> files, and the <code>objects</code> and <code>refs</code> directories. These are the core parts of Git. The <code>objects</code> directory stores all the content for your database, the <code>refs</code> directory stores pointers into commit objects in that data (branches, tags, remotes and more), the <code>HEAD</code> file points to the branch you currently have checked out, and the <code>index</code> file is where Git stores your staging area information. You’ll now look at each of these sections in detail to see how Git operates.</p> </div> <div id="nav"><a href="/book/en/v2/Git-and-Other-Systems-Summary">prev</a> | <a href="/book/en/v2/Git-Internals-Git-Objects">next</a></div> </div> </div> </div> </div> <footer> <div class="site-source"> <a href="/site">About this site</a><br> Patches, suggestions, and comments are welcome. </div> <div class="sfc-member"> Git is a member of <a href="/sfc">Software Freedom Conservancy</a> </div> </footer> <a href="#top" class="no-js scrollToTop" id="scrollToTop" data-label="Scroll to top"> <img src="/images/icons/chevron-up@2x.png" width="20" height="20" alt="scroll-to-top"/> </a> <script src="/js/jquery-1.7.1.min.js"></script> <script src="/js/jquery-ui-1.8.18.custom.min.js"></script> <script src="/js/jquery.defaultvalue.js"></script> <script src="/js/session.min.js"></script> <script src="/js/application.min.js"></script> </div> </body> </html>

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Git - Plumbing and Porcelain