Git - Reset Demystified

<!DOCTYPE html> <html lang="id"> <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 - Reset Demystified</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" action="/search/results"> <input id="search-text" name="search" placeholder="Type / to search entire site…" autocomplete="off" type="text" /> </form> <div id="search-results"></div> </header> </div> <div class="inner"> <div id="content-wrapper"> <div tabindex="1" class="sidebar-btn"></div> <aside class="sidebar" id="sidebar"> <nav> <ul> <li> <a href="/about">About</a> <ul> </ul> </li> <li> <a href="/doc" class="active">Documentation</a> <ul class="expanded"> <li> <a href="/docs">Reference</a> </li> <li> <a href="/book" class="active">Book</a> </li> <li> <a href="/videos">Videos</a> </li> <li> <a href="/doc/ext">External Links</a> </li> </ul> </li> <li> <a href="/downloads">Downloads</a> <ul > <li> <a href="/downloads/guis">GUI Clients</a> </li> <li> <a href="/downloads/logos">Logos</a> </li> </ul> </li> <li> <a href="/community">Community</a> </li> </ul> <hr class="sidebar"> <p> This book is available in <a href="/book/en/v2/Git-Tools-Reset-Demystified">English</a>. </p> <p> Full translation available in <table> <tr><td><a href="/book/az/v2/Git-Al%c9%99tl%c9%99ri-Reset-Demystified">azərbaycan dili</a>,</td></tr> <tr><td><a href="/book/bg">български език</a>,</td></tr> <tr><td><a href="/book/de/v2/Git-Tools-Reset-entzaubert">Deutsch</a>,</td></tr> <tr><td><a href="/book/es/v2/Herramientas-de-Git-Reiniciar-Desmitificado">Español</a>,</td></tr> <tr><td><a href="/book/fr/v2/Utilitaires-Git-Reset-d%c3%a9mystifi%c3%a9">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%e3%81%95%e3%81%be%e3%81%96%e3%81%be%e3%81%aa%e3%83%84%e3%83%bc%e3%83%ab-%e3%83%aa%e3%82%bb%e3%83%83%e3%83%88%e3%82%b3%e3%83%9e%e3%83%b3%e3%83%89%e8%a9%b3%e8%aa%ac">日本語</a>,</td></tr> <tr><td><a href="/book/ko/v2/Git-%eb%8f%84%ea%b5%ac-Reset-%eb%aa%85%ed%99%95%ed%9e%88-%ec%95%8c%ea%b3%a0-%ea%b0%80%ea%b8%b0">한국어</a>,</td></tr> <tr><td><a href="/book/nl/v2/Git-Tools-Reset-ontrafeld">Nederlands</a>,</td></tr> <tr><td><a href="/book/ru/v2/%d0%98%d0%bd%d1%81%d1%82%d1%80%d1%83%d0%bc%d0%b5%d0%bd%d1%82%d1%8b-Git-%d0%a0%d0%b0%d1%81%d0%ba%d1%80%d1%8b%d1%82%d0%b8%d0%b5-%d1%82%d0%b0%d0%b9%d0%bd-reset">Русский</a>,</td></tr> <tr><td><a href="/book/sl/v2/Orodja-Git-Demistifikacija-ponastavitve">Slovenščina</a>,</td></tr> <tr><td><a href="/book/tl/v2/Mga-Git-na-Kasangkapan-Ang-Reset-Demystified">Tagalog</a>,</td></tr> <tr><td><a href="/book/uk/v2/%d0%86%d0%bd%d1%81%d1%82%d1%80%d1%83%d0%bc%d0%b5%d0%bd%d1%82%d0%b8-Git-%d0%a3%d1%81%d0%b2%d1%96%d0%b4%d0%be%d0%bc%d0%bb%d0%b5%d0%bd%d0%bd%d1%8f-%d1%81%d0%ba%d0%b8%d0%b4%d0%b0%d0%bd%d0%bd%d1%8f-reset">Українська</a></td></tr> <tr><td><a href="/book/zh/v2/Git-%e5%b7%a5%e5%85%b7-%e9%87%8d%e7%bd%ae%e6%8f%ad%e5%af%86">简体中文</a>,</td></tr> </table> </p> <p> Partial translations available in <table> <tr><td><a href="/book/cs/v2/Git-Tools-Reset-Demystified">Čeština</a>,</td></tr> <tr><td><a href="/book/mk/v2/Git-%d0%90%d0%bb%d0%b0%d1%82%d0%ba%d0%b8-Reset-Demystified">Македонски</a>,</td></tr> <tr><td><a href="/book/pl/v2/Narz%c4%99dzia-Gita-Reset-Demystified">Polski</a>,</td></tr> <tr><td><a href="/book/sr/v2/%d0%93%d0%b8%d1%82-%d0%b0%d0%bb%d0%b0%d1%82%d0%b8-%d0%94%d0%b5%d0%bc%d0%b8%d1%81%d1%82%d0%b8%d1%84%d0%b8%d0%ba%d0%be%d0%b2%d0%b0%d0%bd%d0%b8-%d1%80%d0%b5%d1%81%d0%b5%d1%82">Српски</a>,</td></tr> <tr><td><a href="/book/uz/v2/Git-Tools-Reset-Demystified">Ўзбекча</a>,</td></tr> <tr><td><a href="/book/zh-tw/v2/Git-%e5%b7%a5%e5%85%b7-Reset-Demystified">繁體中文</a>,</td></tr> </table> </p> <p> Translations started for <table> <tr><td><a href="/book/be/v2/Git-Tools-Reset-Demystified">Беларуская</a>,</td></tr> <tr><td><a href="/book/fa/v2/Git-Tools-Reset-Demystified" dir="rtl">فارسی</a>,</td></tr> <tr><td><a href="/book/id/v2/Git-Tools-Reset-Demystified">Indonesian</a>,</td></tr> <tr><td><a href="/book/it/v2/Git-Tools-Reset-Demystified">Italiano</a>,</td></tr> <tr><td><a href="/book/ms/v2/Git-Tools-Reset-Demystified">Bahasa Melayu</a>,</td></tr> <tr><td><a href="/book/pt-br/v2/Git-Tools-Reset-Demystified">Português (Brasil)</a>,</td></tr> <tr><td><a href="/book/pt-pt/v2/Ferramentas-do-Git-Reset-Demystified">Português (Portugal)</a>,</td></tr> <tr><td><a href="/book/sv/v2/Git-Tools-Reset-Demystified">Svenska</a>,</td></tr> <tr><td><a href="/book/tr/v2/Git-Ara%c3%a7lar%c4%b1-Reset-Komutunun-Gizemleri">Türkçe</a>.</td></tr> </table> </p> <hr class="sidebar"/> <p> The source of this book is <a href="https://github.com/progit/progit2-id">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/id/v2/Memulai-Tentang-Version-Control">Memulai</a></h2> <ol> <li> 1.1 <a href="/book/id/v2/Memulai-Tentang-Version-Control">Tentang Version Control</a> </li> <li> 1.2 <a href="/book/id/v2/Memulai-Sejarah-Singkat-Git">Sejarah Singkat Git</a> </li> <li> 1.3 <a href="/book/id/v2/Memulai-Dasar-dasar-Git">Dasar-dasar Git</a> </li> <li> 1.4 <a href="/book/id/v2/Memulai-Command-Line">Command Line</a> </li> <li> 1.5 <a href="/book/id/v2/Memulai-Memasang-Git">Memasang Git</a> </li> <li> 1.6 <a href="/book/id/v2/Memulai-Pengaturan-Awal-Git">Pengaturan Awal Git</a> </li> <li> 1.7 <a href="/book/id/v2/Memulai-Mendapatkan-Bantuan">Mendapatkan Bantuan</a> </li> <li> 1.8 <a href="/book/id/v2/Memulai-Kesimpulan">Kesimpulan</a> </li> </ol> </li> <li class='chapter'> <h2>2. <a href="/book/id/v2/Git-Basics-Mendapatkan-Repository-Git">Git Basics</a></h2> <ol> <li> 2.1 <a href="/book/id/v2/Git-Basics-Mendapatkan-Repository-Git">Mendapatkan Repository Git</a> </li> <li> 2.2 <a href="/book/id/v2/Git-Basics-Recording-Changes-to-the-Repository">Recording Changes to the Repository</a> </li> <li> 2.3 <a href="/book/id/v2/Git-Basics-Viewing-the-Commit-History">Viewing the Commit History</a> </li> <li> 2.4 <a href="/book/id/v2/Git-Basics-Undoing-Things">Undoing Things</a> </li> <li> 2.5 <a href="/book/id/v2/Git-Basics-Working-with-Remotes">Working with Remotes</a> </li> <li> 2.6 <a href="/book/id/v2/Git-Basics-Tagging">Tagging</a> </li> <li> 2.7 <a href="/book/id/v2/Git-Basics-Alias-Git">Alias Git</a> </li> <li> 2.8 <a href="/book/id/v2/Git-Basics-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>3. <a href="/book/id/v2/Git-Branching-Branches-in-a-Nutshell">Git Branching</a></h2> <ol> <li> 3.1 <a href="/book/id/v2/Git-Branching-Branches-in-a-Nutshell">Branches in a Nutshell</a> </li> <li> 3.2 <a href="/book/id/v2/Git-Branching-Basic-Branching-and-Merging">Basic Branching and Merging</a> </li> <li> 3.3 <a href="/book/id/v2/Git-Branching-Branch-Management">Branch Management</a> </li> <li> 3.4 <a href="/book/id/v2/Git-Branching-Branching-Workflows">Branching Workflows</a> </li> <li> 3.5 <a href="/book/id/v2/Git-Branching-Remote-Branches">Remote Branches</a> </li> <li> 3.6 <a href="/book/id/v2/Git-Branching-Rebasing">Rebasing</a> </li> <li> 3.7 <a href="/book/id/v2/Git-Branching-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>4. <a href="/book/id/v2/Git-di-Server-Protokol">Git di Server</a></h2> <ol> <li> 4.1 <a href="/book/id/v2/Git-di-Server-Protokol">Protokol</a> </li> <li> 4.2 <a href="/book/id/v2/Git-di-Server-Getting-Git-on-a-Server">Getting Git on a Server</a> </li> <li> 4.3 <a href="/book/id/v2/Git-di-Server-Generating-Your-SSH-Public-Key">Generating Your SSH Public Key</a> </li> <li> 4.4 <a href="/book/id/v2/Git-di-Server-Setting-Up-the-Server">Setting Up the Server</a> </li> <li> 4.5 <a href="/book/id/v2/Git-di-Server-Git-Daemon">Git Daemon</a> </li> <li> 4.6 <a href="/book/id/v2/Git-di-Server-Smart-HTTP">Smart HTTP</a> </li> <li> 4.7 <a href="/book/id/v2/Git-di-Server-GitWeb">GitWeb</a> </li> <li> 4.8 <a href="/book/id/v2/Git-di-Server-GitLab">GitLab</a> </li> <li> 4.9 <a href="/book/id/v2/Git-di-Server-Third-Party-Hosted-Options">Third Party Hosted Options</a> </li> <li> 4.10 <a href="/book/id/v2/Git-di-Server-Ringkasan">Ringkasan</a> </li> </ol> </li> <li class='chapter'> <h2>5. <a href="/book/id/v2/Distributed-Git-Distributed-Workflows">Distributed Git</a></h2> <ol> <li> 5.1 <a href="/book/id/v2/Distributed-Git-Distributed-Workflows">Distributed Workflows</a> </li> <li> 5.2 <a href="/book/id/v2/Distributed-Git-Contributing-to-a-Project">Contributing to a Project</a> </li> <li> 5.3 <a href="/book/id/v2/Distributed-Git-Maintaining-a-Project">Maintaining a Project</a> </li> <li> 5.4 <a href="/book/id/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/id/v2/GitHub-Pengaturan-dan-Konfigurasi-Akun">GitHub</a></h2> <ol> <li> 6.1 <a href="/book/id/v2/GitHub-Pengaturan-dan-Konfigurasi-Akun">Pengaturan dan Konfigurasi Akun</a> </li> <li> 6.2 <a href="/book/id/v2/GitHub-Contributing-to-a-Project">Contributing to a Project</a> </li> <li> 6.3 <a href="/book/id/v2/GitHub-Maintaining-a-Project">Maintaining a Project</a> </li> <li> 6.4 <a href="/book/id/v2/GitHub-Mengelola-Organization">Mengelola Organization</a> </li> <li> 6.5 <a href="/book/id/v2/GitHub-Scripting-GitHub">Scripting GitHub</a> </li> <li> 6.6 <a href="/book/id/v2/GitHub-Ringkasan">Ringkasan</a> </li> </ol> </li> <li class='chapter'> <h2>7. <a href="/book/id/v2/Git-Tools-Revision-Selection">Git Tools</a></h2> <ol> <li> 7.1 <a href="/book/id/v2/Git-Tools-Revision-Selection">Revision Selection</a> </li> <li> 7.2 <a href="/book/id/v2/Git-Tools-Interactive-Staging">Interactive Staging</a> </li> <li> 7.3 <a href="/book/id/v2/Git-Tools-Stashing-and-Cleaning">Stashing and Cleaning</a> </li> <li> 7.4 <a href="/book/id/v2/Git-Tools-Signing-Your-Work">Signing Your Work</a> </li> <li> 7.5 <a href="/book/id/v2/Git-Tools-Searching">Searching</a> </li> <li> 7.6 <a href="/book/id/v2/Git-Tools-Rewriting-History">Rewriting History</a> </li> <li> 7.7 <a href="/book/id/v2/Git-Tools-Reset-Demystified" class="active">Reset Demystified</a> </li> <li> 7.8 <a href="/book/id/v2/Git-Tools-Advanced-Merging">Advanced Merging</a> </li> <li> 7.9 <a href="/book/id/v2/Git-Tools-Rerere">Rerere</a> </li> <li> 7.10 <a href="/book/id/v2/Git-Tools-Debugging-with-Git">Debugging with Git</a> </li> <li> 7.11 <a href="/book/id/v2/Git-Tools-Submodules">Submodules</a> </li> <li> 7.12 <a href="/book/id/v2/Git-Tools-Bundling">Bundling</a> </li> <li> 7.13 <a href="/book/id/v2/Git-Tools-Replace">Replace</a> </li> <li> 7.14 <a href="/book/id/v2/Git-Tools-Credential-Storage">Credential Storage</a> </li> <li> 7.15 <a href="/book/id/v2/Git-Tools-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>8. <a href="/book/id/v2/Kostumisasi-Git-Konfigurasi-Git">Kostumisasi Git</a></h2> <ol> <li> 8.1 <a href="/book/id/v2/Kostumisasi-Git-Konfigurasi-Git">Konfigurasi Git</a> </li> <li> 8.2 <a href="/book/id/v2/Kostumisasi-Git-Git-Attributes">Git Attributes</a> </li> <li> 8.3 <a href="/book/id/v2/Kostumisasi-Git-Git-Hooks">Git Hooks</a> </li> <li> 8.4 <a href="/book/id/v2/Kostumisasi-Git-An-Example-Git-Enforced-Policy">An Example Git-Enforced Policy</a> </li> <li> 8.5 <a href="/book/id/v2/Kostumisasi-Git-Ringkasan">Ringkasan</a> </li> </ol> </li> <li class='chapter'> <h2>9. <a href="/book/id/v2/Git-and-Other-Systems-Git-as-a-Client">Git and Other Systems</a></h2> <ol> <li> 9.1 <a href="/book/id/v2/Git-and-Other-Systems-Git-as-a-Client">Git as a Client</a> </li> <li> 9.2 <a href="/book/id/v2/Git-and-Other-Systems-Migrating-to-Git">Migrating to Git</a> </li> <li> 9.3 <a href="/book/id/v2/Git-and-Other-Systems-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>10. <a href="/book/id/v2/Git-Internals-Plumbing-and-Porcelain">Git Internals</a></h2> <ol> <li> 10.1 <a href="/book/id/v2/Git-Internals-Plumbing-and-Porcelain">Plumbing and Porcelain</a> </li> <li> 10.2 <a href="/book/id/v2/Git-Internals-Git-Objects">Git Objects</a> </li> <li> 10.3 <a href="/book/id/v2/Git-Internals-Git-References">Git References</a> </li> <li> 10.4 <a href="/book/id/v2/Git-Internals-Packfiles">Packfiles</a> </li> <li> 10.5 <a href="/book/id/v2/Git-Internals-The-Refspec">The Refspec</a> </li> <li> 10.6 <a href="/book/id/v2/Git-Internals-Transfer-Protocols">Transfer Protocols</a> </li> <li> 10.7 <a href="/book/id/v2/Git-Internals-Maintenance-and-Data-Recovery">Maintenance and Data Recovery</a> </li> <li> 10.8 <a href="/book/id/v2/Git-Internals-Environment-Variables">Environment Variables</a> </li> <li> 10.9 <a href="/book/id/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/id/v2/Appendix-A:-Git-in-Other-Environments-Graphical-Interfaces">Appendix A: Git in Other Environments</a></h2> <ol> <li> A1.1 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Graphical-Interfaces">Graphical Interfaces</a> </li> <li> A1.2 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Visual-Studio">Git in Visual Studio</a> </li> <li> A1.3 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Eclipse">Git in Eclipse</a> </li> <li> A1.4 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Bash">Git in Bash</a> </li> <li> A1.5 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Zsh">Git in Zsh</a> </li> <li> A1.6 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Git-in-Powershell">Git in Powershell</a> </li> <li> A1.7 <a href="/book/id/v2/Appendix-A:-Git-in-Other-Environments-Summary">Summary</a> </li> </ol> </li> <li class='chapter'> <h2>A2. <a href="/book/id/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/id/v2/Appendix-B:-Embedding-Git-in-your-Applications-Command-line-Git">Command-line Git</a> </li> <li> A2.2 <a href="/book/id/v2/Appendix-B:-Embedding-Git-in-your-Applications-Libgit2">Libgit2</a> </li> <li> A2.3 <a href="/book/id/v2/Appendix-B:-Embedding-Git-in-your-Applications-JGit">JGit</a> </li> </ol> </li> <li class='chapter'> <h2>A3. <a href="/book/id/v2/Appendix-C:-Git-Commands-Setup-and-Config">Appendix C: Git Commands</a></h2> <ol> <li> A3.1 <a href="/book/id/v2/Appendix-C:-Git-Commands-Setup-and-Config">Setup and Config</a> </li> <li> A3.2 <a href="/book/id/v2/Appendix-C:-Git-Commands-Getting-and-Creating-Projects">Getting and Creating Projects</a> </li> <li> A3.3 <a href="/book/id/v2/Appendix-C:-Git-Commands-Basic-Snapshotting">Basic Snapshotting</a> </li> <li> A3.4 <a href="/book/id/v2/Appendix-C:-Git-Commands-Branching-and-Merging">Branching and Merging</a> </li> <li> A3.5 <a href="/book/id/v2/Appendix-C:-Git-Commands-Sharing-and-Updating-Projects">Sharing and Updating Projects</a> </li> <li> A3.6 <a href="/book/id/v2/Appendix-C:-Git-Commands-Inspection-and-Comparison">Inspection and Comparison</a> </li> <li> A3.7 <a href="/book/id/v2/Appendix-C:-Git-Commands-Debugging">Debugging</a> </li> <li> A3.8 <a href="/book/id/v2/Appendix-C:-Git-Commands-Patching">Patching</a> </li> <li> A3.9 <a href="/book/id/v2/Appendix-C:-Git-Commands-Email">Email</a> </li> <li> A3.10 <a href="/book/id/v2/Appendix-C:-Git-Commands-External-Systems">External Systems</a> </li> <li> A3.11 <a href="/book/id/v2/Appendix-C:-Git-Commands-Administration">Administration</a> </li> <li> A3.12 <a href="/book/id/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>7.7 Git Tools - Reset Demystified</h1> <div> <h2 id="_git_reset">Reset Demystified</h2> <div class="paragraph"> <p>Before moving on to more specialized tools, let’s talk about <code>reset</code> and <code>checkout</code>. These commands are two of the most confusing parts of Git when you first encounter them. They do so many things, that it seems hopeless to actually understand them and employ them properly. For this, we recommend a simple metaphor.</p> </div> <div class="sect3"> <h3 id="_the_three_trees">The Three Trees</h3> <div class="paragraph"> <p>An easier way to think about <code>reset</code> and <code>checkout</code> is through the mental frame of Git being a content manager of three different trees. By “tree” here we really mean “collection of files”, not specifically the data structure. (There are a few cases where the index doesn’t exactly act like a tree, but for our purposes it is easier to think about it this way for now.)</p> </div> <div class="paragraph"> <p>Git as a system manages and manipulates three trees in its normal operation:</p> </div> <table class="tableblock frame-all grid-all stretch"> <colgroup> <col style="width: 33.3333%;"> <col style="width: 66.6667%;"> </colgroup> <thead> <tr> <th class="tableblock halign-left valign-top">Tree</th> <th class="tableblock halign-left valign-top">Role</th> </tr> </thead> <tbody> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock">HEAD</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">Last commit snapshot, next parent</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock">Index</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">Proposed next commit snapshot</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock">Working Directory</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">Sandbox</p></td> </tr> </tbody> </table> <div class="sect4"> <h4 id="_the_head">The HEAD</h4> <div class="paragraph"> <p>HEAD is the pointer to the current branch reference, which is in turn a pointer to the last commit made on that branch. That means HEAD will be the parent of the next commit that is created. It’s generally simplest to think of HEAD as the snapshot of <strong>your last commit</strong>.</p> </div> <div class="paragraph"> <p>In fact, it’s pretty easy to see what that snapshot looks like. Here is an example of getting the actual directory listing and SHA checksums for each file in the HEAD snapshot:</p> </div> <div class="listingblock"> <div class="content"> <pre class="highlight"><code class="language-console" data-lang="console">$ git cat-file -p HEAD tree cfda3bf379e4f8dba8717dee55aab78aef7f4daf author Scott Chacon 1301511835 -0700 committer Scott Chacon 1301511835 -0700 initial commit $ git ls-tree -r HEAD 100644 blob a906cb2a4a904a152... README 100644 blob 8f94139338f9404f2... Rakefile 040000 tree 99f1a6d12cb4b6f19... lib</code></pre> </div> </div> <div class="paragraph"> <p>The <code>cat-file</code> and <code>ls-tree</code> commands are “plumbing” commands that are used for lower level things and not really used in day-to-day work, but they help us see what’s going on here.</p> </div> </div> <div class="sect4"> <h4 id="_the_index">The Index</h4> <div class="paragraph"> <p>The Index is your <strong>proposed next commit</strong>. We’ve also been referring to this concept as Git’s “Staging Area” as this is what Git looks at when you run <code>git commit</code>.</p> </div> <div class="paragraph"> <p>Git populates this index with a list of all the file contents that were last checked out into your working directory and what they looked like when they were originally checked out. You then replace some of those files with new versions of them, and <code>git commit</code> converts that into the tree for a new commit.</p> </div> <div class="listingblock"> <div class="content"> <pre class="highlight"><code class="language-console" data-lang="console">$ git ls-files -s 100644 a906cb2a4a904a152e80877d4088654daad0c859 0 README 100644 8f94139338f9404f26296befa88755fc2598c289 0 Rakefile 100644 47c6340d6459e05787f644c2447d2595f5d3a54b 0 lib/simplegit.rb</code></pre> </div> </div> <div class="paragraph"> <p>Again, here we’re using <code>ls-files</code>, which is more of a behind the scenes command that shows you what your index currently looks like.</p> </div> <div class="paragraph"> <p>The index is not technically a tree structure – it’s actually implemented as a flattened manifest – but for our purposes it’s close enough.</p> </div> </div> <div class="sect4"> <h4 id="_the_working_directory">The Working Directory</h4> <div class="paragraph"> <p>Finally, you have your working directory. The other two trees store their content in an efficient but inconvenient manner, inside the <code>.git</code> folder. The Working Directory unpacks them into actual files, which makes it much easier for you to edit them. Think of the Working Directory as a <strong>sandbox</strong>, where you can try changes out before committing them to your staging area (index) and then to history.</p> </div> <div class="listingblock"> <div class="content"> <pre class="highlight"><code class="language-console" data-lang="console">$ tree . ├── README ├── Rakefile └── lib └── simplegit.rb 1 directory, 3 files</code></pre> </div> </div> </div> </div> <div class="sect3"> <h3 id="_the_workflow">The Workflow</h3> <div class="paragraph"> <p>Git’s main purpose is to record snapshots of your project in successively better states, by manipulating these three trees.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-workflow.png" alt="reset workflow"> </div> </div> <div class="paragraph"> <p>Let’s visualize this process: say you go into a new directory with a single file in it. We’ll call this <strong>v1</strong> of the file, and we’ll indicate it in blue. Now we run <code>git init</code>, which will create a Git repository with a HEAD reference which points to an unborn branch (<code>master</code> doesn’t exist yet).</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex1.png" alt="reset ex1"> </div> </div> <div class="paragraph"> <p>At this point, only the Working Directory tree has any content.</p> </div> <div class="paragraph"> <p>Now we want to commit this file, so we use <code>git add</code> to take content in the Working Directory and copy it to the Index.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex2.png" alt="reset ex2"> </div> </div> <div class="paragraph"> <p>Then we run <code>git commit</code>, which takes the contents of the Index and saves it as a permanent snapshot, creates a commit object which points to that snapshot, and updates <code>master</code> to point to that commit.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex3.png" alt="reset ex3"> </div> </div> <div class="paragraph"> <p>If we run <code>git status</code>, we’ll see no changes, because all three trees are the same.</p> </div> <div class="paragraph"> <p>Now we want to make a change to that file and commit it. We’ll go through the same process; first we change the file in our working directory. Let’s call this <strong>v2</strong> of the file, and indicate it in red.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex4.png" alt="reset ex4"> </div> </div> <div class="paragraph"> <p>If we run <code>git status</code> right now, we’ll see the file in red as “Changes not staged for commit,” because that entry differs between the Index and the Working Directory. Next we run <code>git add</code> on it to stage it into our Index.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex5.png" alt="reset ex5"> </div> </div> <div class="paragraph"> <p>At this point if we run <code>git status</code> we will see the file in green under “Changes to be committed” because the Index and HEAD differ – that is, our proposed next commit is now different from our last commit. Finally, we run <code>git commit</code> to finalize the commit.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-ex6.png" alt="reset ex6"> </div> </div> <div class="paragraph"> <p>Now <code>git status</code> will give us no output, because all three trees are the same again.</p> </div> <div class="paragraph"> <p>Switching branches or cloning goes through a similar process. When you checkout a branch, it changes <strong>HEAD</strong> to point to the new branch ref, populates your <strong>Index</strong> with the snapshot of that commit, then copies the contents of the <strong>Index</strong> into your <strong>Working Directory</strong>.</p> </div> </div> <div class="sect3"> <h3 id="_the_role_of_reset">The Role of Reset</h3> <div class="paragraph"> <p>The <code>reset</code> command makes more sense when viewed in this context.</p> </div> <div class="paragraph"> <p>For the purposes of these examples, let’s say that we’ve modified <code>file.txt</code> again and committed it a third time. So now our history looks like this:</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-start.png" alt="reset start"> </div> </div> <div class="paragraph"> <p>Let’s now walk through exactly what <code>reset</code> does when you call it. It directly manipulates these three trees in a simple and predictable way. It does up to three basic operations.</p> </div> <div class="sect4"> <h4 id="_step_1_move_head">Step 1: Move HEAD</h4> <div class="paragraph"> <p>The first thing <code>reset</code> will do is move what HEAD points to. This isn’t the same as changing HEAD itself (which is what <code>checkout</code> does); <code>reset</code> moves the branch that HEAD is pointing to. This means if HEAD is set to the <code>master</code> branch (ie, you’re currently on the <code>master</code> branch), running <code>git reset 9e5e64a</code> will start by making <code>master</code> point to <code>9e5e64a</code>.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-soft.png" alt="reset soft"> </div> </div> <div class="paragraph"> <p>No matter what form of <code>reset</code> with a commit you invoke, this is the first thing it will always try to do. With <code>reset --soft</code>, it will simply stop there.</p> </div> <div class="paragraph"> <p>Now take a second to look at that diagram and realize what happened: it essentially undid the last <code>git commit</code> command. When you run <code>git commit</code>, Git creates a new commit and moves the branch that HEAD points to up to it. When you <code>reset</code> back to <code>HEAD~</code> (the parent of HEAD), you are moving the branch back to where it was, without changing the Index or Working Directory. You could now update the Index and run <code>git commit</code> again to accomplish what <code>git commit --amend</code> would have done (see <a href="/book/id/v2/ch00/_git_amend">Changing the Last Commit</a>).</p> </div> </div> <div class="sect4"> <h4 id="_step_2_updating_the_index_mixed">Step 2: Updating the Index (--mixed)</h4> <div class="paragraph"> <p>Note that if you run <code>git status</code> now you’ll see in green the difference between the Index and what the new HEAD is.</p> </div> <div class="paragraph"> <p>The next thing <code>reset</code> will do is to update the Index with the contents of whatever snapshot HEAD now points to.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-mixed.png" alt="reset mixed"> </div> </div> <div class="paragraph"> <p>If you specify the <code>--mixed</code> option, <code>reset</code> will stop at this point. This is also the default, so if you specify no option at all (just <code>git reset HEAD~</code> in this case), this is where the command will stop.</p> </div> <div class="paragraph"> <p>Now take another second to look at that diagram and realize what happened: it still undid your last <code>commit</code>, but also <em>unstaged</em> everything. You rolled back to before you ran all your <code>git add</code> and <code>git commit</code> commands.</p> </div> </div> <div class="sect4"> <h4 id="_step_3_updating_the_working_directory_hard">Step 3: Updating the Working Directory (--hard)</h4> <div class="paragraph"> <p>The third thing that <code>reset</code> will do is to make the Working Directory look like the Index. If you use the <code>--hard</code> option, it will continue to this stage.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-hard.png" alt="reset hard"> </div> </div> <div class="paragraph"> <p>So let’s think about what just happened. You undid your last commit, the <code>git add</code> and <code>git commit</code> commands, <strong>and</strong> all the work you did in your working directory.</p> </div> <div class="paragraph"> <p>It’s important to note that this flag (<code>--hard</code>) is the only way to make the <code>reset</code> command dangerous, and one of the very few cases where Git will actually destroy data. Any other invocation of <code>reset</code> can be pretty easily undone, but the <code>--hard</code> option cannot, since it forcibly overwrites files in the Working Directory. In this particular case, we still have the <strong>v3</strong> version of our file in a commit in our Git DB, and we could get it back by looking at our <code>reflog</code>, but if we had not committed it, Git still would have overwritten the file and it would be unrecoverable.</p> </div> </div> <div class="sect4"> <h4 id="_recap">Recap</h4> <div class="paragraph"> <p>The <code>reset</code> command overwrites these three trees in a specific order, stopping when you tell it to:</p> </div> <div class="olist arabic"> <ol class="arabic"> <li> <p>Move the branch HEAD points to <em>(stop here if <code>--soft</code>)</em></p> </li> <li> <p>Make the Index look like HEAD <em>(stop here unless <code>--hard</code>)</em></p> </li> <li> <p>Make the Working Directory look like the Index</p> </li> </ol> </div> </div> </div> <div class="sect3"> <h3 id="_reset_with_a_path">Reset With a Path</h3> <div class="paragraph"> <p>That covers the behavior of <code>reset</code> in its basic form, but you can also provide it with a path to act upon. If you specify a path, <code>reset</code> will skip step 1, and limit the remainder of its actions to a specific file or set of files. This actually sort of makes sense – HEAD is just a pointer, and you can’t point to part of one commit and part of another. But the Index and Working directory <em>can</em> be partially updated, so reset proceeds with steps 2 and 3.</p> </div> <div class="paragraph"> <p>So, assume we run <code>git reset file.txt</code>. This form (since you did not specify a commit SHA or branch, and you didn’t specify <code>--soft</code> or <code>--hard</code>) is shorthand for <code>git reset --mixed HEAD file.txt</code>, which will:</p> </div> <div class="olist arabic"> <ol class="arabic"> <li> <p>Move the branch HEAD points to <em>(skipped)</em></p> </li> <li> <p>Make the Index look like HEAD <em>(stop here)</em></p> </li> </ol> </div> <div class="paragraph"> <p>So it essentially just copies <code>file.txt</code> from HEAD to the Index.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-path1.png" alt="reset path1"> </div> </div> <div class="paragraph"> <p>This has the practical effect of <em>unstaging</em> the file. If we look at the diagram for that command and think about what <code>git add</code> does, they are exact opposites.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-path2.png" alt="reset path2"> </div> </div> <div class="paragraph"> <p>This is why the output of the <code>git status</code> command suggests that you run this to unstage a file. (See <a href="/book/id/v2/ch00/_unstaging">Unstaging a Staged File</a> for more on this.)</p> </div> <div class="paragraph"> <p>We could just as easily not let Git assume we meant “pull the data from HEAD” by specifying a specific commit to pull that file version from. We would just run something like <code>git reset eb43bf file.txt</code>.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-path3.png" alt="reset path3"> </div> </div> <div class="paragraph"> <p>This effectively does the same thing as if we had reverted the content of the file to <strong>v1</strong> in the Working Directory, ran <code>git add</code> on it, then reverted it back to <strong>v3</strong> again (without actually going through all those steps). If we run <code>git commit</code> now, it will record a change that reverts that file back to <strong>v1</strong>, even though we never actually had it in our Working Directory again.</p> </div> <div class="paragraph"> <p>It’s also interesting to note that like <code>git add</code>, the <code>reset</code> command will accept a <code>--patch</code> option to unstage content on a hunk-by-hunk basis. So you can selectively unstage or revert content.</p> </div> </div> <div class="sect3"> <h3 id="_squashing_2">Squashing</h3> <div class="paragraph"> <p>Let’s look at how to do something interesting with this newfound power – squashing commits.</p> </div> <div class="paragraph"> <p>Say you have a series of commits with messages like “oops.”, “WIP” and “forgot this file”. You can use <code>reset</code> to quickly and easily squash them into a single commit that makes you look really smart. (<a href="/book/id/v2/ch00/_squashing">Squashing Commits</a> shows another way to do this, but in this example it’s simpler to use <code>reset</code>.)</p> </div> <div class="paragraph"> <p>Let’s say you have a project where the first commit has one file, the second commit added a new file and changed the first, and the third commit changed the first file again. The second commit was a work in progress and you want to squash it down.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-squash-r1.png" alt="reset squash r1"> </div> </div> <div class="paragraph"> <p>You can run <code>git reset --soft HEAD~2</code> to move the HEAD branch back to an older commit (the first commit you want to keep):</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-squash-r2.png" alt="reset squash r2"> </div> </div> <div class="paragraph"> <p>And then simply run <code>git commit</code> again:</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-squash-r3.png" alt="reset squash r3"> </div> </div> <div class="paragraph"> <p>Now you can see that your reachable history, the history you would push, now looks like you had one commit with <code>file-a.txt</code> v1, then a second that both modified <code>file-a.txt</code> to v3 and added <code>file-b.txt</code>. The commit with the v2 version of the file is no longer in the history.</p> </div> </div> <div class="sect3"> <h3 id="_check_it_out">Check It Out</h3> <div class="paragraph"> <p>Finally, you may wonder what the difference between <code>checkout</code> and <code>reset</code> is. Like <code>reset</code>, <code>checkout</code> manipulates the three trees, and it is a bit different depending on whether you give the command a file path or not.</p> </div> <div class="sect4"> <h4 id="_without_paths">Without Paths</h4> <div class="paragraph"> <p>Running <code>git checkout [branch]</code> is pretty similar to running <code>git reset --hard [branch]</code> in that it updates all three trees for you to look like <code>[branch]</code>, but there are two important differences.</p> </div> <div class="paragraph"> <p>First, unlike <code>reset --hard</code>, <code>checkout</code> is working-directory safe; it will check to make sure it’s not blowing away files that have changes to them. Actually, it’s a bit smarter than that – it tries to do a trivial merge in the Working Directory, so all of the files you <em>haven’t</em> changed in will be updated. <code>reset --hard</code>, on the other hand, will simply replace everything across the board without checking.</p> </div> <div class="paragraph"> <p>The second important difference is how it updates HEAD. Where <code>reset</code> will move the branch that HEAD points to, <code>checkout</code> will move HEAD itself to point to another branch.</p> </div> <div class="paragraph"> <p>For instance, say we have <code>master</code> and <code>develop</code> branches which point at different commits, and we’re currently on <code>develop</code> (so HEAD points to it). If we run <code>git reset master</code>, <code>develop</code> itself will now point to the same commit that <code>master</code> does. If we instead run <code>git checkout master</code>, <code>develop</code> does not move, HEAD itself does. HEAD will now point to <code>master</code>.</p> </div> <div class="paragraph"> <p>So, in both cases we’re moving HEAD to point to commit A, but <em>how</em> we do so is very different. <code>reset</code> will move the branch HEAD points to, <code>checkout</code> moves HEAD itself.</p> </div> <div class="imageblock"> <div class="content"> <img src="/book/id/v2/images/reset-checkout.png" alt="reset checkout"> </div> </div> </div> <div class="sect4"> <h4 id="_with_paths">With Paths</h4> <div class="paragraph"> <p>The other way to run <code>checkout</code> is with a file path, which, like <code>reset</code>, does not move HEAD. It is just like <code>git reset [branch] file</code> in that it updates the index with that file at that commit, but it also overwrites the file in the working directory. It would be exactly like <code>git reset --hard [branch] file</code> (if <code>reset</code> would let you run that) – it’s not working-directory safe, and it does not move HEAD.</p> </div> <div class="paragraph"> <p>Also, like <code>git reset</code> and <code>git add</code>, <code>checkout</code> will accept a <code>--patch</code> option to allow you to selectively revert file contents on a hunk-by-hunk basis.</p> </div> </div> </div> <div class="sect3"> <h3 id="_summary_5">Summary</h3> <div class="paragraph"> <p>Hopefully now you understand and feel more comfortable with the <code>reset</code> command, but are probably still a little confused about how exactly it differs from <code>checkout</code> and could not possibly remember all the rules of the different invocations.</p> </div> <div class="paragraph"> <p>Here’s a cheat-sheet for which commands affect which trees. The “HEAD” column reads “REF” if that command moves the reference (branch) that HEAD points to, and “HEAD” if it moves HEAD itself. Pay especial attention to the <em>WD Safe?</em> column – if it says <strong>NO</strong>, take a second to think before running that command.</p> </div> <table class="tableblock frame-all grid-all stretch"> <colgroup> <col style="width: 42.8571%;"> <col style="width: 14.2857%;"> <col style="width: 14.2857%;"> <col style="width: 14.2857%;"> <col style="width: 14.2858%;"> </colgroup> <thead> <tr> <th class="tableblock halign-left valign-top"></th> <th class="tableblock halign-left valign-top">HEAD</th> <th class="tableblock halign-left valign-top">Index</th> <th class="tableblock halign-left valign-top">Workdir</th> <th class="tableblock halign-left valign-top">WD Safe?</th> </tr> </thead> <tbody> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><strong>Commit Level</strong></p></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>reset --soft [commit]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">REF</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>reset [commit]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">REF</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>reset --hard [commit]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">REF</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock"><strong>NO</strong></p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>checkout [commit]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">HEAD</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><strong>File Level</strong></p></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> <td class="tableblock halign-left valign-top"></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>reset (commit) [file]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> </tr> <tr> <td class="tableblock halign-left valign-top"><p class="tableblock"><code>checkout (commit) [file]</code></p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">NO</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock">YES</p></td> <td class="tableblock halign-left valign-top"><p class="tableblock"><strong>NO</strong></p></td> </tr> </tbody> </table> </div> <div id="nav"><a href="/book/id/v2/Git-Tools-Rewriting-History">prev</a> | <a href="/book/id/v2/Git-Tools-Advanced-Merging">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>

CINXE.COM

Git - Reset Demystified