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@@ -0,0 +1,563 @@ +% vim: set tabstop=4: +% vim: set shiftwidth=4: +% vim: set expandtab: + +\RHpresentationHead{ + \documentclass[pdftex,unicode,xcolor=table,slidestop,compress]{beamer} +} + +\RHarticleHead{ + % This does not work, because of colors, \insertauthor, etc. + \documentclass[a4paper,12pt,pdftex,unicode]{article} + \usepackage[envcountsect]{beamerarticle} +} + +%\usepackage{pgfpages} +\usetheme{Git} +\setbeamertemplate{navigation symbols}{} +\setbeamercovered{transparent=5} + +\usepackage[utf8]{inputenc} +%\usepackage[lang]{babel} +\usepackage{setspace,amsfonts,calc,upquote,hyperref,floatflt,graphicx} +\usepackage[table]{xcolor} +\usepackage{colortbl} +\usepackage[absolute,overlay]{textpos} + +\defverb\verbemail|Random Hacker <rand@hacker.com>| +\defverb\kzakemail|<kzak@redhat.com>| + +% presentation title/author/etc. +\title{Git} +\subtitle{(Why not CVS? ... because Git.)} +\author{Karel Zak\\ +\kzakemail} +\date{} + +% fancy section/part pages? +%\fancySectionOpens +%\fancyPartOpens + + +\begin{document} + +\begin{rhbg} +\begin{frame} + \titlepage +\end{frame} +\end{rhbg} + +\begin{frame}[plain] +\vspace*{30ex} +Copyright \copyright{}\ \ \the\year\ \ Karel Zak.\\ +\vspace*{1ex} +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 +or any later version published by the Free Software Foundation; +with no Invariant Sections, no Front-Cover Texts, and no Back-Cover +Texts. +\end{frame} + +% table of contents +\begin{frame} + \frametitle{Agenda} + \tableofcontents +\end{frame} + +\section{Intro} + +\begin{frame} + \frametitle{What is Git?} + \begin{quote} + ``I'm an egotistical bastard, and I name all my projects after myself. First 'Linux', now 'git'.'' (Linus Torvalds) + \end{quote} + \vspace*{4ex} + \begin{itemize} + \item fast distributed revision control system + \item unusually rich command set + \item provides both high-level operations and full access to internals + \item originally created by Linus Torvalds for kernel development + \item design was inspired by BitKeeper and Monotone + \item GNU General Public License, version 2 + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Basic features} + \begin{itemize} + \item distributed development model + \item support for non-linear development (branching and merging) + \item ready for large projects (very good performance) + \item repositories can be easily published (git://, ssh://, http://, rsync://, ...) + \item cryptographic authentication of history (GPG-signed tags) + \item internally objects are addressed by content (SHA-1) -- no filenames + \item local branches are local only (off-line work) + \end{itemize} +\end{frame} + +\subsection{Development model} + +\begin{frame} + \frametitle{Centralized model} + \resizebox{7cm}{4cm}{\includegraphics{git-centralized.png}} + \begin{itemize} + \item extra policy for write access + \item SCM is not development tool, but source code archive only + \item every change has impact to all developers + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Distributed model} + \resizebox{8cm}{5cm}{\includegraphics{git-distributed.png}} + \begin{itemize} + \item maintainer has full control over primary (his) repository + \item support for non-linear development + \item repositories can be easily published (git://, ssh://, http://, ...) + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Git improves your work manners and habits} + \begin{itemize} + \item + branching and merging is cheap + + \begin{itemize} + \item you can prototyping + \item you can collaborate with others developers on incomplete and unstable stuff + \item you can easily (e.g. every day) rebase your changes to new upstream code + \item often merging (rebase) minimize conflicts between your patches and upstream + \end{itemize} + + \item + small patch is the best patch (patch per feature/change) + + \begin{itemize} + \item reviewers hate huge patches + \item well separated feature or change is easy to revert + \end{itemize} + \end{itemize} +\end{frame} + +\section{Implementation} + + +\begin{frame} + \frametitle{Internal objects} + \begin{block}{} + All objects are content-addressable by SHA-1. + \end{block} + + \begin{description}[references] + \item[commit] refers to ``tree'' and ``parent`` (connection into the project history) + \item[tree] represents the state of a single directory (list of ``blob'' objects and subtrees) + \item[blob] contains file data without any other structure + \item[references] are human readable names for commits; for example tags, see files under .git/refs/heads/. + \end{description} +\end{frame} + +\begin{frame} + \frametitle{Internal objects} + \resizebox{8cm}{4cm}{\includegraphics{git-objdb.png}} + \begin{description}[commit] + \item[commit] -- connection between ``tree'' and ``parent`` + \item[tree] -- state of a single directory + \item[blob] -- contain file data + \end{description} +\end{frame} + + +\begin{frame}[containsverbatim] + \frametitle{Trust} + \begin{itemize} + \item everything is content-addressed and based on SHA-1 + \item two trees are same when HEAD SHA-1 are same + \item tags could be GPG-signed + \end{itemize} + + \begin{exampleblock}{} + \scriptsize{ + \begin{verbatim} + $ git tag -v v2.13 + object 49ef7acdf77066ed05a6c828c261d332c4f54644 + type commit + tag v2.13 + tagger Karel Zak <kzak@redhat.com> Tue Aug 28 01:01:35 2007 +0200 + + stable release v2.13 + gpg: Signature made Tue 28 Aug 2007 01:01:35 AM CEST using DSA key ID DC06D885 + gpg: Good signature from "Karel Zak <kzak@redhat.com>" \end{verbatim} + } + \end{exampleblock} +\end{frame} + + +\subsection{Naming revisions} + +\begin{frame}[containsverbatim] + \frametitle{Object reference} + \defverb\ngrandparent|commit~n| + \defverb\nparent|commit^n| + \begin{description}[ref@\{date\}] + \item[SHA-1] 40-hexdigit object name + \item[tag] human readable name for commit + \item[\nparent] N-th parent + \item[\ngrandparent] N-th generation grand-parent of the named commit object, following only the first parent. + \item[ref@\{date\}] specify the value of the ref at a prior point in time + \item[:/text] commit whose commit message starts with the specified text + \item[HEAD] refers to the head of the current branch + \end{description} + + \begin{exampleblock}{} + \begin{verbatim} rev~3 = rev^^^ = rev^1^1^1 \end{verbatim} + \end{exampleblock} + + \begin{exampleblock}{} + \begin{verbatim} $ git reset HEAD^ \end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Ranges} + \begin{description}[r1...r2] + \item[r1..r2] commits reachable from r2 but exclude the ones reachable from r1 + \item[r1...r2] set of commits that are reachable from either one of r1 or r2 but not from both + \end{description} + + \begin{exampleblock}{} + \begin{verbatim} $ git log v2.13..v2.14 \end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame} + \frametitle{"tree-ish"} + Lots of commands take a tree as an argument. A tree can be referred to in many different ways, by: + + \begin{itemize} + \item name for that tree + \item name of a commit that refers to the tree + \item name of a branch whose head refers to that tree + \end{itemize} +\end{frame} + +\section{Repositories} + +\begin{frame}[containsverbatim] + \frametitle{Create a repository} + + \begin{itemize} + \item create a new repository + \begin{exampleblock}{} + \small{ + \begin{verbatim} + $ mkdir project + $ cd project + $ git init \end{verbatim} + } + \end{exampleblock} + \item clone an existing remote repository ("origin" repository) + \begin{exampleblock}{} + \small{ \begin{verbatim} $ git clone http://foo.com/project \end{verbatim} } + \end{exampleblock} + \item add a next remote repository + \begin{exampleblock}{} + \small{ + \begin{verbatim} $ git config remote.bar.url git://bar.com/project + $ git config remote.bar.fetch master:refs/remotes/bar/master + $ git fetch bar \end{verbatim} + } + \end{exampleblock} + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Visualisation} + \includegraphics[width=0.9\textwidth]{gitk.png} +\end{frame} + +\section{Branches} + +\begin{frame}[containsverbatim] + \frametitle{Branches} + \begin{exampleblock}{} + \begin{verbatim} + o--o--o <-- Branch A + / + o--o--o--o--o <-- master + \ + o--o--o <-- Branch B \end{verbatim} + \end{exampleblock} + + \begin{description}[branch head] + \item[branch] is line of development + \item[branch head] is a reference to the most recent commit on a branch + \end{description} + \vspace*{1ex} + Branches, remote-tracking branches, and tags are all references to commits. + +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Manipulating branches} + \defverb\branchname|<branch>| + \begin{itemize} + \item \structure{git branch} lists, creates, or deletes branches + \item \structure{git checkout \branchname} makes the current branch \branchname, updating the working directory + \item \structure{git checkout -b \branchname} creates a new branch \branchname check it out + \item \structure{git show-branch} shows branches and their commits + \item \structure{git diff \branchname..\branchname} diffs between branches + \end{itemize} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Rebase branch} + \begin{exampleblock}{Before} + \begin{verbatim} + A---B---C topic + / + D---E---F---G master \end{verbatim} + \end{exampleblock} + + \begin{exampleblock}{Command} + \begin{verbatim} $ git rebase master topic \end{verbatim} + \end{exampleblock} + + \begin{exampleblock}{After} + \begin{verbatim} + A---B---C topic + / + D---E---F---G master \end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Edit 2nd commit from the top} + \begin{enumerate} + \item create a temporary branch (rewind to the commit in question): + \begin{exampleblock}{} + \begin{verbatim} $ git checkout -f -b tmp HEAD~2 \end{verbatim} + \end{exampleblock} + + \item reset old changes and redo the commit + \begin{exampleblock}{} + \begin{verbatim} + $ git reset HEAD^ + $ vim foo.c + $ git commit -a -c ORIG_HEAD \end{verbatim} + \end{exampleblock} + + \item replay the later changes to the master: + \begin{exampleblock}{} + \begin{verbatim} $ git rebase --onto tmp master~2 master \end{verbatim} + \end{exampleblock} + + \item clean up (delete) the temporary branch + \begin{exampleblock}{} + \begin{verbatim} $ git branch -D tmp \end{verbatim} + \end{exampleblock} + \end{enumerate} +\end{frame} + +\section{Real life with Git} + +\begin{frame} + \frametitle{Changes in project history} + \begin{itemize} + \item the latest patches -- (\texttt{git reset}) reset current HEAD + + \item deep in project history + \begin{itemize} + \item rebease + \begin{itemize} + \item impact to all rebased commits (new SHA-1) + \item impact to all tags + + \item useless for publicly pushed changes + \end{itemize} + \item patch revert (\texttt{git revert}) + \begin{itemize} + \item zero impact to project history + \end{itemize} + \end{itemize} + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Send a patch} + Basic rules: + \begin{itemize} + \item one patch per e-mail + \item don't use stupid e-mail clients (e.g. Outlook) + \item (don't use attachments) + \item export patches by \texttt{git format-patch} + \item send patches by \texttt{git send-email} + + \item well formatted patch is possible to apply by \texttt{git am} + + \item don't forget to keep correct authorship (e.g when you are not author of the patch) + + \item use commit messages -- a patch without comment is incomplete crap + \end{itemize} +\end{frame} + +\section{Commands} + +\begin{frame}[containsverbatim] + \frametitle{Syntax} + \begin{itemize} + \item \texttt{git <commandname> [options]} + \item \texttt{git-<commandname> [options]} + \end{itemize} + + \begin{exampleblock}{High level} + \begin{verbatim} $ git commit -a -s -m "cool change" \end{verbatim} + \end{exampleblock} + \begin{exampleblock}{Low level} + \begin{verbatim} $ git rev-list --pretty=oneline v2.13.. \end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame} + \frametitle{Basic commands} + \begin{description}[git format-path] + \item[git init] creates en empty repository at \texttt{./.git} + \item[git add] adds file contents to the next commit + \item[git reset] resets current HEAD + \item[git status] shows the working tree status + \item[git commit] records changes to the repository + \item[git log] shows commit log + \item[git show] shows commit (or another object) + \item[git format-path] exports a change + \item[git send-email] sends patch(s) + \item[git am] applies a series of patches from a mailbox + \end{description} +\end{frame} + +\subsection{Commits and patches} + +\begin{frame}[containsverbatim] + \frametitle{Commit changes} + \begin{block}{} + \begin{verbatim} git commit [options] [<file>] \end{verbatim} + \end{block} + \begin{itemize} + \item \structure{-a} commits all modified or deleted files + \item \structure{-s} adds Signed-off-by line at the end of the commit message + + \item \structure{-c ORIG\_HEAD} reuses a commit message (e.g. from previously reseted commit) + \item \structure{--author "\verbemail"} overrides the author name + + \item starts \structure{\$EDITOR} for commit message (or \texttt{-m "<commit message>"}) + \end{itemize} + + \begin{exampleblock}{} + \begin{verbatim} $ git commit -a -s\end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Export patches to files} + \begin{block}{} + \begin{verbatim} git format-patch [options] <since|range> \end{verbatim} + \end{block} + \begin{itemize} + \item creates one file per patch + \item created patches are usable by \structure{git am} + \end{itemize} + \begin{exampleblock}{} + \scriptsize{ + \begin{verbatim} +$ git format-patch -o ~/ HEAD~5 +/home/kzak/0001-setterm-opened-file-leaving-unclosed.patch +/home/kzak/0002-sfdisk-opened-files-leaving-unclosed.patch +/home/kzak/0003-blockdev-fix-opened-file-leaving-unclosed.patch +/home/kzak/0004-tailf-opened-file-leaving-unclosed.patch +/home/kzak/0005-tests-use-losetup-s.patch \end{verbatim} + } + \end{exampleblock} +\end{frame} + +\begin{frame} + \frametitle{Patch description} + \includegraphics[width=0.9\textwidth]{git-patch.png} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Send patches by e-mail} + \begin{block}{} + \begin{verbatim} git send-email [options] <file|dir> \end{verbatim} + \end{block} + Takes the patches given on the command line and emails them out.\\ + \begin{itemize} + \item no attachments + \item no broken patch format + \item correct subject line + \end{itemize} + \begin{exampleblock}{} + \begin{verbatim} +$ git send-email --to "God <father@heaven.com>" \ + ~/0001-make-this-world-better.patch \end{verbatim} + \end{exampleblock} +\end{frame} + +\begin{frame}[containsverbatim] + \frametitle{Browsing changes} + \begin{description}[git whatchanged] + \item[git log] shows commit logs + \item[git show] shows one or more objects (blobs, trees, tags and commits) + \item[git blame] shows what revision and author last modified each line of a file + \item[git whatchanged] shows logs with difference each commit introduces + \end{description} + \begin{exampleblock}{} + \begin{scriptsize} + \begin{verbatim} +$ git log v2.5.. # commits since v2.5 +$ git log test..master # commits reachable from master + # but not test +$ git log --since="2 weeks ago" # commits from the last 2 weeks +$ git log Makefile # commits which modify Makefile +$ git log --pretty=format:"%h [%an]" # commit log in format + # "sha-1 [Author Name]" +$ git blame -L 10,15 foo.c # who modified code between lines + 10 and 15 +$ git show c1a47c171b # shows selecte object (commit) \end{verbatim} + \end{scriptsize} + \end{exampleblock} +\end{frame} + +\section{Misc} + +\begin{frame} + \frametitle{Gitweb} + \includegraphics[width=0.9\textwidth]{gitweb.png} +\end{frame} + +\begin{frame} + \frametitle{References} + \begin{thebibliography}{Git User's Manua} + \bibitem[Git User's Manual]{GitUserManual} + Git User's Manual + \newblock {\url{http://www.kernel.org/pub/software/scm/git/docs/user-manual.html}} + \bibitem[Git Tutorial]{GitTutorial} + A tutorial introduction to git + \newblock {\url{http://www.kernel.org/pub/software/scm/git/docs/tutorial.html}} + \bibitem[The perfect patch]{PerfectPatch} + The perfect patch + \newblock {\url{http://www.zip.com.au/~akpm/linux/patches/stuff/tpp.txt}} + \end{thebibliography} +\end{frame} + +\begin{frame} + \hfill + \begin{center} + {\Huge The end.} + \par\vspace*{0.5cm} + Thanks for listening. + \end{center} + \hfill +\end{frame} + +\end{document} + + |