revision control

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Version Control With Git: Powerful Tools and Techniques for Collaborative Software Development by Jon Loeliger, Matthew McCullough

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continuous integration, Debian, distributed revision control, GnuPG, pull request, revision control, web application, web of trust

A tool that manages and tracks different versions of software or other content is referred to generically as a version control system (VCS), a source code manager (SCM), a revision control system (RCS), and several other permutations of the words “revision,” “version,” “code,” “content,” “control,” “management,” and “system.” Although the authors and users of each tool might debate esoterics, each system addresses the same issue: develop and maintain a repository of content, provide access to historical editions of each datum, and record all changes in a log. In this book, the term version control system (VCS) is used to refer generically to any form of revision control system. This book covers Git, a particularly powerful, flexible, and low-overhead version control tool that makes collaborative development a pleasure.

Version Control with Git Jon Loeliger Matthew McCullough Published by O’Reilly Media Beijing ⋅ Cambridge ⋅ Farnham ⋅ Köln ⋅ Sebastopol ⋅ Tokyo Preface Audience Although some familiarity with revision control systems will be good background material, a reader who is not familiar with any other system will still be able to learn enough about basic Git operations to be productive in a short while. More advanced readers should be able to gain insight into some of Git’s internal design and thus master some of its more powerful techniques. The main intended audience of this book should be familiar and comfortable with the Unix shell, basic shell commands, and general programming concepts. Assumed Framework Almost all examples and discussions in this book assume the reader has a Unix-like system with a command-line interface.

In order to support the sheer volume of update operations that would be made on the Linux kernel alone, he knew that both individual update operations and network transfer operations would have to be very fast. To save space and thus transfer time, compression and “delta” techniques would be needed. Using a distributed model instead of a centralized model also ensured that network latency would not hinder daily development. Maintain Integrity and Trust Because Git is a distributed revision control system, it is vital to obtain absolute assurance that data integrity is maintained and is not somehow being altered. How do you know the data hasn’t been altered in transition from one developer to the next? Or from one repository to the next? Or, for that matter, that the data in a Git repository is even what it purports to be? Git uses a common cryptographic hash function, called Secure Hash Function (SHA1), to name and identify objects within its database.

 

pages: 509 words: 92,141

The Pragmatic Programmer by Andrew Hunt, Dave Thomas

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A Pattern Language, Broken windows theory, business process, buy low sell high, c2.com, combinatorial explosion, continuous integration, database schema, domain-specific language, general-purpose programming language, Grace Hopper, if you see hoof prints, think horses—not zebras, index card, loose coupling, Menlo Park, MVC pattern, premature optimization, Ralph Waldo Emerson, revision control, Schrödinger's Cat, slashdot, sorting algorithm, speech recognition, traveling salesman, urban decay, Y2K

[URL 32] Perl Power Tools ⇒ www.perl.com/pub/language/ppt/ A project to reimplement the classic Unix command set in Perl, making the commands available on all platforms that support Perl (and that's a lot of platforms). Source Code Control Tools [URL 33] RCS—Revision Control System ⇒ www.cs.purdue.edu/homes/trinkle/RCS/ GNU source code control system for Unix and Windows NT. [URL 34] CVS—Concurrent Version System ⇒ www.cvshome.com Freely available source code control system for Unix and Windows NT. Extends RCS by supporting a client-server model and concurrent access to files. [URL 35] Aegis Transaction-Based Configuration Management ⇒ http://www.canb.auug.org.au/~millerp/aegis.html A process-oriented revision control tool that imposes project standards (such as verifying that checked-in code passes tests). [URL 36] ClearCase ⇒ www.rational.com Version control, workspace and build management, process control.

., 217 who ate fish, 34 Plain text, 73 vs. binary format, 73 drawbacks, 74 executable documents, 251 leverage, 75 obsolescence, 74 and easier testing, 76 Unix, 76 Polymorphism, 111 Post-it note, 53, 55 Powerbuilder, 55 The Practice of Programming, 99 Pragmatic programmer characteristics, xviii e-mail address, xxiii Web site, xxiii Pre- and postcondition, 110, 113, 114 Predicate logic, 110 Preprocessor, 114 Presentation, 20 Problem domain, 58, 66 metadata, 146 Problem solving, 213 checklist for, 214 Productivity, 10, 35 Programming by coincidence, 173 Programming staff expense of, 237 Programming Windows, 265 Project glossary, 210 “heads”, 228 saboteur, 244 schedules, 68 see also Automation; Team, project Project librarian, 33, 226 Prototyping, 53, 216 architecture, 55 disposable code, 56 kinds of, 54 and programming languages, 55 and tracer code, 51 using, 54 Publish/subscribe protocol, 158 Pugh, Greg, 95n Purify, 136 PVCS Configuration Management, 271 Python, 55, 99, 267 Q Quality control, 9 requirements, 11 teams, 225 Quarry worker’s creed, xx Quicksort algorithm, 180 R Rational Unified Process, 227n Raymond, Eric S., 273 RCS, see Revision Control System Real-world data, 243 Refactoring, 5, 185 automatic, 187 and design, 186 testing, 187 time constraints, 185 Refactoring browser, 187, 268 Refinement, excessive, 11 Regression, 76, 197, 232, 242 Relationship has-a, 304 kind-of, 111, 304 Releases, and SCCS, 87 Remote Method Invocation (RMI), 128 exception handling, 39 Remote procedure call (RPC), 29, 39 Repository, 87 Requirement, 11, 202 business problem, 203 changing, 26 creep, 209 DBC, 110 distribution, 211 documenting, 204 in domain language, 58 expressing as invariant, 116 formal methods, 220 glossary, 210 over specifying, 208 and policy, 203 usability testing, 241 user interface, 203 Researching, 15 Resource balancing, 129 C++ exceptions, 132 checking, 135 coupled code, 130 dynamic data structures, 135 encapsulation in class, 132 Java, 134 nest allocations, 131 Response set, 141, 242 Responsibility, 2, 250, 258 Reuse, 33, 36 Reversibility, 44 flexible architecture, 46 Revision Control System (RCS), 250, 271 Risk management, 13 orthogonality, 36 RMI, see Remote Method Invocation Rock-n-roll, 47 RPC, see Remote procedure call Rubber ducking, 3, 95 Rules engine, 169 S Saboteur, 244 Samba, 272 Sample programs, see Example code Sather, 114, 268 SCCS, see Source code control system Schedule, project, 68 Schrödinger, Erwin (and his cat), 47 Scope, requirement, 209 Screen scraping, 61 Scripting language, 55, 145 Secure hash, 74 sed, 99 Sedgewick, Robert, 183 Self-contained components, see Orthogonality; Cohesion Semantic invariant, 116, 135 sendmail program, 60 Sequence diagram, 158 Server code, 196 Services, design using, 154 Shell, command, 77 vs.

., 273 RCS, see Revision Control System Real-world data, 243 Refactoring, 5, 185 automatic, 187 and design, 186 testing, 187 time constraints, 185 Refactoring browser, 187, 268 Refinement, excessive, 11 Regression, 76, 197, 232, 242 Relationship has-a, 304 kind-of, 111, 304 Releases, and SCCS, 87 Remote Method Invocation (RMI), 128 exception handling, 39 Remote procedure call (RPC), 29, 39 Repository, 87 Requirement, 11, 202 business problem, 203 changing, 26 creep, 209 DBC, 110 distribution, 211 documenting, 204 in domain language, 58 expressing as invariant, 116 formal methods, 220 glossary, 210 over specifying, 208 and policy, 203 usability testing, 241 user interface, 203 Researching, 15 Resource balancing, 129 C++ exceptions, 132 checking, 135 coupled code, 130 dynamic data structures, 135 encapsulation in class, 132 Java, 134 nest allocations, 131 Response set, 141, 242 Responsibility, 2, 250, 258 Reuse, 33, 36 Reversibility, 44 flexible architecture, 46 Revision Control System (RCS), 250, 271 Risk management, 13 orthogonality, 36 RMI, see Remote Method Invocation Rock-n-roll, 47 RPC, see Remote procedure call Rubber ducking, 3, 95 Rules engine, 169 S Saboteur, 244 Samba, 272 Sample programs, see Example code Sather, 114, 268 SCCS, see Source code control system Schedule, project, 68 Schrödinger, Erwin (and his cat), 47 Scope, requirement, 209 Screen scraping, 61 Scripting language, 55, 145 Secure hash, 74 sed, 99 Sedgewick, Robert, 183 Self-contained components, see Orthogonality; Cohesion Semantic invariant, 116, 135 sendmail program, 60 Sequence diagram, 158 Server code, 196 Services, design using, 154 Shell, command, 77 vs.

 

pages: 239 words: 64,812

Geek Sublime: The Beauty of Code, the Code of Beauty by Vikram Chandra

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Alan Turing: On Computable Numbers, with an Application to the Entscheidungsproblem, Apple II, barriers to entry, Berlin Wall, British Empire, business process, conceptual framework, create, read, update, delete, crowdsourcing, East Village, European colonialism, finite state, Firefox, Flash crash, glass ceiling, Grace Hopper, haute couture, iterative process, Jaron Lanier, John von Neumann, land reform, London Whale, Paul Graham, pink-collar, revision control, Silicon Valley, Silicon Valley ideology, Skype, Steve Jobs, Steve Wozniak, theory of mind, Therac-25, Turing machine, wikimedia commons, women in the workforce

This is not a trivial task. For example, every programmer needs to use a revision control system to track changes and easily branch and merge versions of code. The best-regarded revision control system today is Git, created by Linus Torvalds (and named, incidentally, after his famous cantankerousness).21 Git’s interface is command-line driven and famously UNIX-y and complex, and for the newbie its inner workings are mysterious. In response to a blog post titled “Git Is Simpler Than You Think,” an irritated Reddit commenter remarked, “Yes, also a nuclear submarine is simpler than you think … once you learn how it works.”22 I myself made three separate attempts to learn how Git worked, gave up, was frustrated enough by other revision control systems to return, and finally had to read a 265-page book to acquire enough competence to use the thing.

 

pages: 184 words: 12,922

Pragmatic Version Control Using Git by Travis Swicegood

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continuous integration, en.wikipedia.org, Firefox, revision control

In fact, the most reliable method for converting a CVS repository to Git is to convert it to a Subversion repository first using the cvs2svn command.2 cvs2svn is a tool for converting a CVS repository to a Subversion repository. Git ships with a tool for importing CVS repositories called git cvsimport. Since the cvs2svn command is much more stable to a Git repository, we’ll focus on it. To start with, you need to get revision control system (RCS) files from your CVS repository. Once you have those, you need to convert them to an SVN dump file using the cvs2svn tool: prompt> cd /path/to/cvs-rcs-files prompt> cvs2svn --dumpfile=svndump Creating the dump file allows you to filter out any unnecessary data by using tools such as svndumpfilter.3 With your new svndump prepared, now you need to create a Subversion repository to import it into.

Prepared exclusively for Trieu Nguyen Download at Boykma.Com Index A Adding files, 52–56 Adding, remote repositories, 106–107 adduser, 150 Aliases, 58 apt-get, 167 Archive, 46 AsciiDoc, 34 Authentication, 103 B Bisecting repository, 131f, 132f, 131–134 Branches, 22f, 21–22, 43–45, 65–79 changes in (reflog), 129 checking out, 68 commands for, 160 conflict handling, 74–77 creating, 67–68 defined, 66–67 deleting, 77–78 merging, 69–73 names for, valid, 114–115 rebasing, 125–128 release, 112–114 renaming, 78–79 see also Merging Branching and merging, 10 Buffer, 58 Bugs, 113, 119, 131 C Centralized repository model, 16 Changes, undoing, 91–94 Checked-out branch, 68 cherry-pick, 73 Cloning remote repositories, 103–104 Prepared exclusively for Trieu Nguyen repositories, 48, 118 Color control, 32, 42, 61 Commit messages, 42, 83 Commits breaking down, 98 cherry-picking, 71 orphaned, 129f reordering, 96 squashing, 70, 96 submodules and, 119 see also Changes, undoing Committing files, 55–58 Configuration, 31–33 Configuration management (CM), 25 Conflict resolution, 23, 74–77 Conflicts, 74 Content tracking, 88–91 Conventions, 13, 110 Copying files, 62 CPAN, 142 Creating branches, 67–68 CVS, 138f importing from, 146 cvs2svn, 146 D de Bie, Pieter, 33 Deleting branches, 77–78 Directed acyclic graph (DAG), 66 Directories, tracking, 56 Distributed architecture, 10 Distributed version control systems (DVCSs), 10, 15, 16 see also Git Documentation, 35, see History, repository DVCSs, see Distributed version control systems Download at Boykma.Com E CLIPSE G IT PLUG - IN E Eclipse Git plug-in, 169 Empty directories, 56 Errors, 144 Exporting repository, 124–125 F Feature branches, 70 Fetching, remote repositories, 104–105 Files adding, 52–56 committing, 55–58 copying, 62 differences between, 60 hunks, 54 ignoring, 63, 64 managing, 61–64 manipulation of, 18–19 status and history of, 58–61 Fink, 26 G Git branches, 22 built-in help for, 34–35 commands in, 122 configuration of, 31–33 conventions, 13 development of, 10 forums for, 173 GUI, 33, 34f hashes in, 39 installation of, 30f, 31f, 26–31, 32f merging, 23 migrating to, 136–146 git-svn, 140–142 CVS commands in, 138f importing from CVS, 146 importing from Subversion, 141–144 pushing to Subversion, 145 Subversion commands in, 137f SVN communication, 139f, 136–139 tracking changes from Subversion, 143–145 network protocols, 101f, 102f, 100–103 protocol for, 101 pulling, 19 Prepared exclusively for Trieu Nguyen 176 GIT - GUI pushing, 17 setup of, 158 strengths of, 10 submodules, 116–121 URL components, 101, 102f user manual, 172 website for, 172 see also Gitosis git, 13 git add, 52, 57, 62, 127 git archive, 47, 124, 125 git bisect, 131, 132, 134 git blame, 86, 89, 90 git branch, 43, 66, 68, 77, 110, 111, 113, 130 git checkout, 45, 68, 121 git checkout HEAD, 106 git cherry-pick, 72, 73 git clone, 48, 103 git commit, 56, 58, 92 git config, 58 git daemon, 154, 155 git diff, 60, 85, 86, 89 git fetch, 104 git gc, 123, 124, 143 git init, 103 #git IRC channel, 173 git log, 81, 84, 86, 97, 112, 113, 130 Git Mailing List, 173 git merge, 70, 71 git mergetool, 76, 126 git mv, 62 git pull, 104 git push, 105, 152 git rebase, 45, 95, 126–129, 144 git remote add, 107 git remote rm, 108 git reset, 73, 94, 98 git revert, 93 git rm, 62 git status, 59, 63, 71, 73, 121 git submodule, 117, 119, 120 git submodule add, 117 git submodule init, 119 git submodule update, 119, 121 git svn clone, 141, 143 git svn dcommit, 145 git svn fetch, 144 git svn rebase, 143–145 git tag, 110, 111 git-gui, 168 Download at Boykma.Com GIT - SH git-sh, 171 git-svn, 140–142 GitHub, 13, 102, 109, 171 gitk, 33, 167 GitNub, 170 Gitorious, 169, 172 Gitosis, 147–155 admin setup, 149–150 configuration, 151–152 dependencies, 148 initialization, 151 installation of, 147, 149 public repository, 154–155 repositories for, 152–154 server configuration, 150 gitosis-init, 151 gitweb, 168 GitX, 168 Graphical user interface, see GUI GUI, 33, 34f gzip, 47 H Hashes options for, 84 SHA-1, 39 Help, built-in, 34–35 History, repository, 80–99 blame, 86–88 changes, undoing, 91–94 commands for, 162 compacting, 123–124 content tracking, 88–91 log of, 81–82 reviews of, 94–99 revision ranges, 82–85 version differences, 85–86 Hook scripts, 147 Hosting, 171–172 HTTP, 102 Hunk, 54 I Ignoring files, 63, 64 Installation, 30f, 31f, 26–31, 32f Gitosis, 147, 149 Linux, 27–28 Mac OS X, 28 Windows, 28–31, 32f Interactive mode, 54 Prepared exclusively for Trieu Nguyen 177 REFLOG K Keys, 150, 152 Komodo IDE, 169 L Linux installation, 27–28 Locking, 24 Log messages, 42, 81, 82 M Mac OS X CPAN, 142 FileMerge Utility, 77f installation, 28 MacPorts, 26, 140, 142 MacVim, 63, 169 Makefiles, 26 Master branch, 43, 45, 112 Merging, 22–23, 69–73 Milestones, marking, 110–112 Moving files, 62 MSys, 29 N Naming, 110, 114–115 Network protocols, 101f, 102f, 100–103 nohup, 155 O Online resources, 13 Optimistic locking, 24 Organization, 19–20 Orphaned commits, 129f P patch mode, 54 Perl bindings, 140 Port 9418, 101 Practices of an Agile Developer: Working in the Real World, Subramaniam & Hunt, 141 Public key, 150, 152 Pulling, 19 Pushing, 17, 19, 105–106, 145 Python, 148 R Rebasing, 45 Rebasing branches, 125–128 reflog, 129f, 128–130 Download at Boykma.Com R EGULAR EXPRESSIONS Regular expressions, 87 Release branches, 43, 45, 112–114 Releases, 45f, 46f, 44–47, 116 Remote repositories, 100–107 adding, 106–107 cloning, 103–104 commands for, 164 fetching, 104–105 network protocols, 101f, 102f, 100–103 pushing changes, 105–106 Remote repository see also Repository Renaming branches, 78–79 Renaming files, 62 repo.or.cz, 171 Repository, 16–17 adding files, 52–56 bisecting, 131f, 132f, 131–134 branches and, 43–44 changing, 37–39 cloning, 48, 118 committing to, 55–58 creating, 37 exporting, 124–125 file management, 61–64 file status and history, 58–61 Gitosis and, 152–154 history, compacting, 123–124 hosting services for, 171–172 log messages for, 42 milestones, marking, 110–112 private, 95 public, 154–155 release branches, 112–114 releases and, 45f, 46f, 44–47 shrinking, 143 tracking, 115–116 tracking changes in, 40–41, 129f, 128–130 tracking, submodules for, 116–121 see also History, repository; Remote repositories Resources bundles, 167 online, 13, 172–173 repository hosting, 171–172 third-party tools, 168–171 Reverting commits, 93 Revision control system (RCS), 146 Revisions, 18, 82 Prepared exclusively for Trieu Nguyen 178 V ERSION CONTROL SYSTEMS (VCS S ) S Server setup, see Gitosis SHA (secure hash algorithm), 39 Squashing, 70, 96 SSH, 101 SSH public key, 149, 152 ssh-keygen, 149, 150 Staged changes, 52 Staging area, 52 Status check, 59 Straight merging, 69 Submodules, 116–121 Subversion, 11, 58 commands for, 165 commands in Git, 137f Git communication and, 139f, 136–139 importing to Git, 141–144 keep up-to-date with, 143–145 pushing changes to, 145 SVN/Core.pm missing file, 140 Syntax, names, 114 T Tags, 20–21, 44, 84, 110–112, 114–115 Tcl/Tk GUI toolkit, 33 TextMate Git Bundle, 169 TicGit, 170 Torvalds, Linus, 10 Tracking, projects, 115–116 Tracking, tags, 20–21 Trunk, 43 U Upstream repository, 19 URL components, 101, 102f Username, 32 V VCSCommand, 169 VCSs, see Version control systems Version control systems (VCSs) benefits of, 10 branches, 22f, 21–22 configuration management, 25 defined, 15 file manipulation, 18–19 history, 80–99 blame, 86–88 changes, undoing, 91–94 Download at Boykma.Com V ERSIONS content tracking, 88–91 log, 81–82 reviews of, 94–99 revision ranges, 82–85 version differences, 85–86 locking, 24 merging, 22–23 organizing, 19–20 repository, 16–17, 37 tags, 20–21 Prepared exclusively for Trieu Nguyen 179 W ORKING what to store in, 17 working trees, 18 see also Git Versions, 85–86, 155 Virtual machines (VMs), 106 W Windows installation, 28–31, 32f Working trees, 18 TREES Download at Boykma.Com Web 2.0 Welcome to the Web, version 2.0.

 

pages: 236 words: 67,823

Hacking Vim 7.2 by Kim Schulz

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Alexey Pajitnov wrote Tetris, Debian, revision control, sorting algorithm

[ 206 ] Appendix A A typical IDE, if we talk of programs such as MS Visual Studio®, basically consists of the following things: • An editor with automatic indentation, syntax coloring, and autocompletion • An integrated compiler that makes it possible to jump directly to compile errors in the code • An integrated debugger that makes it possible to step through the code • A file explorer such that you can look through the files to add to the project • A project browser to look through the files included in the project • A tag browser to look through the tags (definitions, functions, methods, classes) • An easy way to jump between files, definitions, and so on • Maybe integration with some version / revision control system So are all of these things, at all, possible in Vim? Now, let's go through all of the items, one by one, and see how we can get that functionality in Vim. The first item is obvious, as Vim is an editor it does just that. The second item in the list is the integration with a compiler. Vim is often used for programming, so it is built with support for compiler integration. For most common programming languages, the settings for compiler integration in Vim are already set.

You can find the script and information about how to install it at http://vim-taglist.sourceforge.net. [ 208 ] Appendix A When it comes to moving around in the Vim editor window itself, Vim already has the shortcuts gf and gd, which take you to the file or declaration of the tag under the cursor. This makes it very fast to jump around in the files. Finally, there is the integration with version / revision control systems such as CVS, SVN, and Perforce. As with all the other functionality that you need to construct a Vim IDE, this integration is of course also available via scripts. I would recommend the following scripts for the mentioned systems: • CVS and SVN, which are located at http://vim.sourceforge.net/ scripts/script.php?script_id=90 • Perforce, which is located at http://vim.sourceforge.net/scripts/ script.php?

 

pages: 372 words: 67,140

Jenkins Continuous Integration Cookbook by Alan Berg

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anti-pattern, continuous integration, Debian, en.wikipedia.org, Firefox, job automation, performance metric, revision control, web application, x509 certificate

For example: <build> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>properties-maven-plugin</artifactId> <version>1.0-alpha-2</version> <executions> <execution> <phase>initialize</phase> <goals> <goal>read-project-properties</goal> </goals> <configuration> <files> <file>${fullpath.to.properties}</file> </files> </configuration> </execution> </executions> </plugin> </plugins> </build> If you use a relative path to the properties file, then the file can reside in your Revision control system. If you use a full path, then the property file can be stored on the Jenkins server. The second option is preferable if sensitive passwords, such as for database connections, are included. Jenkins has the ability to ask for variables when you run a Job manually. This is called a Parameterized build (https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+Build). At the build time, you can choose your property files by selecting from a choice of property file locations.

The test phase occurs before the generation of a JAR file, and thus avoids creating a warning about an empty JAR. As the name suggests, this phase is useful for testing before packaging. The second example script highlights the strength of combining Groovy with Ant. The SCP task (http://Ant.apache.org/manual/Tasks/scp.html) is run a large number of times across many servers. The script first asks for the USERNAME and password, avoiding storage on your file system or your revision control system. The Groovy script expects you to inject the variables host: full_path_to_location and myfile. Notice the similarity between the Ant SCP task and the way it is expressed in the pom_ant_contrib.xml file. There's more... Creating custom property files on the fly allows you to pass on information from one Jenkins Job to another. You can create property files through AntBuilder using the echo task.

 

pages: 351 words: 123,876

Beautiful Testing: Leading Professionals Reveal How They Improve Software (Theory in Practice) by Adam Goucher, Tim Riley

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Albert Einstein, barriers to entry, Black Swan, call centre, continuous integration, Debian, en.wikipedia.org, Firefox, Grace Hopper, index card, Isaac Newton, natural language processing, p-value, performance metric, revision control, six sigma, software as a service, software patent, the scientific method, Therac-25, Valgrind, web application

To a developer, it is clear that a defect lives in the source code Tools such as Bugs Everywhere§ operate on the purist concept that, since bugs ultimately reside in the source code, defect tracking should live alongside the code and use the same revision control system (e.g., CVS, SVN, Mercurial). This does have significant advantages, especially for small systems where the entire code base can live within one revision control system. When a defect is fixed, both the patched source code and updated defect report are checked into the revision control system, and the correspondence between the defect state and the defect report state are correctly and automatically propagated to branches of the source tree without requiring the developer or software QA person to maintain an ad-hoc set of cross references in the source tree and the state in the defect database.

 

pages: 1,758 words: 342,766

Code Complete (Developer Best Practices) by Steve McConnell

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Ada Lovelace, Albert Einstein, Buckminster Fuller, call centre, choice architecture, continuous integration, data acquisition, database schema, fault tolerance, Grace Hopper, haute cuisine, if you see hoof prints, think horses—not zebras, index card, inventory management, iterative process, late fees, loose coupling, Menlo Park, place-making, premature optimization, revision control, slashdot, sorting algorithm, statistical model, Tacoma Narrows Bridge, the scientific method, Thomas Kuhn: the structure of scientific revolutions, Turing machine, web application

If you're working on a program with other people and want to see the changes they have made since the last time you worked on the code, a comparator tool such as Diff will make a comparison of the current version with the last version of the code you worked on and show the differences. If you discover a new defect that you don't remember encountering in an older version of a program, rather than seeing a neurologist about amnesia, you can use a comparator to compare current and old versions of the source code, determine exactly what changed, and find the source of the problem. This functionality is often built into revision-control tools. Merge Tools One style of revision control locks source files so that only one person can modify a file at a time. Another style allows multiple people to work on files simultaneously and handles merging changes at check-in time. In this working mode, tools that merge changes are critical. These tools typically perform simple merges automatically and query the user for merges that conflict with other merges or that are more involved.

Will programmers write unit tests for their code regardless of whether they write them first or last? Will programmers step through their code in the debugger before they check it in? Will programmers integration-test their code before they check it in? Will programmers review or inspect each other's code? Cross-Reference For more details on quality assurance, see Chapter 20, "The Software-Quality Landscape." Tools Have you selected a revision control tool? Have you selected a language and language version or compiler version? Have you selected a framework such as J2EE or Microsoft .NET or explicitly decided not to use a framework? Have you decided whether to allow use of nonstandard language features? Have you identified and acquired other tools you'll be using—editor, refactoring tool, debugger, test framework, syntax checker, and so on?

A few simple guidelines can prevent refactoring missteps. Opening up a working system is more like opening up a human brain and replacing a nerve than opening up a sink and replacing a washer. Would maintenance be easier if it was called "Software Brain Surgery?" —Gerald Weinberg Save the code you start with Before you begin refactoring, make sure you can get back to the code you started with. Save a version in your revision control system, or copy the correct files to a backup directory. Keep refactorings small Some refactorings are larger than others, and exactly what constitutes "one refactoring" can be a little fuzzy. Keep the refactorings small so that you fully understand all the impacts of the changes you make. The detailed refactorings described in Refactoring (Fowler 1999) provide many good examples of how to do this.

 

pages: 125 words: 28,222

Growth Hacking Techniques, Disruptive Technology - How 40 Companies Made It BIG – Online Growth Hacker Marketing Strategy by Robert Peters

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Airbnb, bounce rate, business climate, citizen journalism, crowdsourcing, Google Glasses, Jeff Bezos, Lean Startup, Menlo Park, Network effects, new economy, pull request, revision control, ride hailing / ride sharing, search engine result page, sharing economy, Skype, TaskRabbit

The company claims that inbound leads converts twice as often as outbound leads because they are of a higher quality in the first place. This is the continued justification for the emphasis on free content creation that caters to the point of view of the potential customer. GitHub GitHub, a web-based software development environment, launched in 2008, initially focused on facilitating projects that used the Git system for revision control. The idea for the site was developed on a whim over a weekend. In 3 years and 8 months, however, it grew to become a site with a million code repositories. In December 2013, that number reached a staggering 10 million. At its core, GitHub is a success because it solves a problem. The Git version-control system developed by Linus Torvalds in 2005 made collaboration possible for Linux kernel development, but it was far from an “easy” solution.

 

pages: 1,065 words: 229,099

Real World Haskell by Bryan O'Sullivan, John Goerzen, Donald Stewart, Donald Bruce Stewart

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bash_history, database schema, Debian, distributed revision control, domain-specific language, en.wikipedia.org, Firefox, general-purpose programming language, job automation, p-value, Plutocrats, plutocrats, revision control, sorting algorithm, transfer pricing, type inference, web application, Y Combinator

We love working with them; we still use them every day; but usually, we prefer Haskell. Haskell in Industry and Open Source Here are just a few examples of large software systems that have been created in Haskell. Some of these are open source, while others are proprietary products: ASIC and FPGA design software (Lava, products from Bluespec, Inc.) Music composition software (Haskore) Compilers and compiler-related tools (most notably GHC) Distributed revision control (Darcs) Web middleware (HAppS, products from Galois, Inc.) The following is a sample of some of the companies using Haskell in late 2008, taken from the Haskell wiki: ABN AMRO An international bank. It uses Haskell in investment banking, in order to measure the counterparty risk on portfolios of financial derivatives. Anygma A startup company. It develops multimedia content creation tools using Haskell.

It can only look at the name of a directory entry; it cannot, for example, find out whether it’s a file or a directory. This means that our attempt to use simpleFind will list directories ending in .c as well as files with the same extension. The second problem is that simpleFind gives us no control over how it traverses the filesystem. To see why this is significant, consider the problem of searching for a source file in a tree managed by the Subversion revision control system. Subversion maintains a private .svn directory in every directory that it manages; each one contains many subdirectories and files that are of no interest to us. While we can easily filter out any path containing .svn, it’s more efficient to simply avoid traversing these directories in the first place. For example, one of us has a Subversion source tree containing 45,000 files, 30,000 of which are stored in 1,200 different .svn directories.

, Introducing Local Variables–The Offside Rule and Whitespace in an Expression, Local Functions, Global Variables global, Local Functions, Global Variables local, Introducing Local Variables–The Offside Rule and Whitespace in an Expression W Wadler, Philip, Further Reading waitFor function, Finding the Status of a Thread -Wall GHC option, Compilation Options and Interfacing to C weak head normal form (WHNF), Normal Form and Head Normal Form, Separating Algorithm from Evaluation, Strictness and Tail Recursion web client programming, Extended Example: Web Client Programming–Main Program well typed rules, Strong Types where clause, The where Clause, The Anatomy of a Haskell Module whitespace in expressions, The Offside Rule and Whitespace in an Expression–The case Expression, A Note About Tabs Versus Spaces vs. tab characters, A Note About Tabs Versus Spaces WHNF (weak head normal form), Normal Form and Head Normal Form, Separating Algorithm from Evaluation, Strictness and Tail Recursion widgets (GUI programming), Glade Concepts wild card patterns, The Wild Card Pattern Windows, installing GHC/Haskell libraries, Windows withForeignPtr function, Pattern Matching with Substrings withTransaction function, Transactions Word type, Numeric Types Word16 type, Numeric Types Word32 type, Numeric Types Word64 type, Numeric Types Word8 type, Numeric Types writeChan function, Chan Is Unbounded writeFile function, readFile and writeFile Writer monad, The Writer Monad and Lists WriterT monad transformer, Motivation: Boilerplate Avoidance X x86_64 assembly, Tuning the Generated Assembly XML, Extended Example: Web Client Programming, Glade Concepts widget descriptions saved as, Glade Concepts xor function, Numeric Types Z zero-width escape sequences, The Zero-Width Escape Sequence zip function, Working with Several Lists at Once zipWith function, Working with Several Lists at Once About the Authors Bryan O'Sullivan is an Irish hacker and writer who likes distributed systems, open source software, and programming languages. He was a member of the initial design team for the Jini network service architecture (subsequently open sourced as Apache River). He has made significant contributions to, and written a book about, the popular Mercurial revision control system. He lives in San Francisco with his wife and sons. Whenever he can, he runs off to climb rocks. John Goerzen is an American hacker and author. He has written a number of real-world Haskell libraries and applications, including the HDBC database interface, the ConfigFile configuration file interface, a podcast downloader, and various other libraries relating to networks, parsing, logging, and POSIX code.

 

pages: 671 words: 228,348

Pro AngularJS by Adam Freeman

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business process, create, read, update, delete, en.wikipedia.org, Google Chrome, information retrieval, inventory management, MVC pattern, place-making, premature optimization, revision control, single page application, web application

This fragment comes from Listing 10-2 and sets up a one-way data binding on the todos.length property, which I explain in the following section. Some developers don’t like the attribute approach, and—surprisingly often—attributes cause problems in development tool chains. Some JavaScript libraries make assumptions about attribute names, and some restrictive revision control systems won’t let HTML content be committed with nonstandard attributes. (I encounter this most often in large corporations where the revision control system is managed by a central group that lags far behind the needs of the development teams it supports.) If you can’t or won’t use custom attributes, then you can configure directives using the standard class attribute, as follows: ... There are <span class="ng-bind: todos.length"></span> items ... 236 Chapter 10 ■ Using Binding and Template Directives The value of the class attribute is the name of the directive, followed by a colon, followed by the configuration for the directive.

The controller I am going to create will be used throughout the application—something I refer to as the top-level controller, although this is a term of my own invention—and I define this controller in its own file. Later, I’ll start to group multiple related controllers in a file, but I put the top-level controller in its own file. Listing 6-2 shows the contents of the controllers/sportsStore.js file, which I created for this purpose. ■■Tip  The reason I keep the top-level controller in a separate file is so that I can keep an eye on it when it changes in a revision control system. The top-level controller tends to change a lot during the early stages of development, when the application is taking shape, and I don’t want the avalanche of change notifications to mask when other controllers are being altered. Later in the project, when the main functionality is complete, the top-level controller changes infrequently, but when it does change, there is a potential for breaking pretty much everything else in the application.

 

pages: 496 words: 70,263

Erlang Programming by Francesco Cesarini

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cloud computing, fault tolerance, finite state, loose coupling, revision control, RFC: Request For Comment, sorting algorithm, Turing test, type inference, web application

Shell Modes: Interactive and Embedded The Erlang shell is started by default in what we call interactive mode. This means that at startup, only the modules the runtime system needs are loaded. Other code is dynamically loaded when a fully qualified function is made to a function in that module. In embedded mode, all the modules listed in a binary boot file are loaded at startup. After startup, calls to modules that have not been loaded result in a runtime error. Embedded mode enforces strict revision control, as it requires that all modules are available at startup. Lastly, it does not impact the soft real-time aspects of the system by stopping, searching, and loading a module during a time-critical operation, as might be the case for interactive mode. You can choose your mode by starting Erlang with the erl -mode Mode directive, where Mode is either embedded or interactive. Purging Modules The code server can get rid of or purge old versions of a module by calling code:purge(Module), but if any processes were running that code, they will first be terminated, after which the old version of the code is deleted.

In large systems, you would expect to find quite a few of them. 355 In a huge and complex system, without any knowledge of the module in which the entry was corrupted, you would have to find the tuple {error, unknown_msg}, potentially having to search through millions of lines of code. Once you found the tuple, inserting an io:format/2 statement that prints the error and process information would not solve the problem, as in live systems, processes come and go and millions of entries are inserted and deleted from ETS tables each hour. In addition, because this is a live system with strict revision control, code changes must be tested and approved before being deployed. This option, even if it’s tempting, would result in a slow turnaround time. Don’t get wound up on release procedures and slow turnaround times from the quality assurance team, however, as you can do better! In Erlang, the first thing a developer or support engineer would consider doing is to turn on the trace facility for all calls to the ets:insert/2 function.

 

Python Web Development With Django by Jeff Forcier

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create, read, update, delete, database schema, Debian, en.wikipedia.org, Firefox, full text search, loose coupling, MVC pattern, revision control, Silicon Valley, slashdot, web application

Version Control If you’re developing any kind of software at all, and you’re not using version control, you’re missing out.Version control systems keep a complete revision history of your project, enabling you to rewind your code to any point in time (for example, to the hour before you made that innocent-looking change that broke something you didn’t notice for a week). Older version control systems such as SCCS (Source Code Control System) and RCS (Revision Control System) were simple, either maintaining the original versions of files plus deltas (minor changes to files between versions) or vice versa—keeping the latest editions of files and applying “backward deltas.” One limitation of such systems was the controlled files lived on and were modified on the same server. As software development has progressed, especially in the open source community, it became clear the existing systems were awkward for distributed group development, hence leading to more modern version control systems such as CVS (Concurrent 314 Appendix C Tools for Practical Django Development Versions System), an improved and distributed offshoot of RCS, and later, the Subversion project, which was meant to be “a better CVS” and a compelling replacement for it.

See deleting render_to_response function (Django), 131 repetition/duplication of sequences (Python), 16 rapid development in Django, 85 repositories (version control systems), copying, 317 raw strings (Django), 22 repr function (Python), 25 raw strings (Python), 22, 64 REQUEST data structure (Django), 124 in regular expressions, 47 request middleware (Django), 126-127 raw_post_data variable (request objects), 125 request objects (Django), 123-125 RCS (Revision Control System), 313 requests (Web development), 78 re module (Python), 47 response middleware (Django), 127 read method (Python), 34 response objects (Django), 125-126 readlines method (Python), 34 responses (Web development), 78 recording changesets, 317 reverse method (Django), 108 redirection (command line), 289-291 reverse method (Python), 51 redirection operators (<>), 291 reversed function (Python), 18, 26, 51 references of function objects (Python), 36-37 root URLs (Django), regexes for, 118 rows (in database tables), 78 367 368 rstrip method (Python) rstrip method (Python), 21, 34 running development runserver, 59-61 runserver command (Django), 60 S safe filter (Django), 197 save method (Django), 143-145, 168 saving model-based forms (Django), 143-145 thumbnail images (photo gallery example), 168-169 SCCS (Source Code Control System), 313 schema definition with initial SQL files, 113 lists, 14, 17-18 generator expressions, 19 list comprehensions, 18-19 sorting, 18, 51 operations on, 16 slicing, 15-16 strings, 14, 19-21 formatting, 22-24 string designators, 22 tuples, 15, 24 in Django, 24-25 single-element tuples, 48 unpacking in functions, 40 scripts.

 

Django Book by Matt Behrens

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create, read, update, delete, database schema, distributed revision control, en.wikipedia.org, Firefox, full text search, loose coupling, MVC pattern, revision control, school choice, slashdot, web application

Usually it’s in a place like (In Ubuntu 12.04) /usr/local/lib/python2.7/dist-packages/. Installing the “master” Version The latest and greatest Django development version is referred to as master, and it’s available from Django’s git repository. You should consider installing this version if you want to work on the bleeding edge, or if you want to contribute code to Django itself. Git is a free, open source distributed revision-control system, and the Django team uses it to manage changes to the Django codebase. You can use a Git client to grab the very latest Django source code and, at any given time, you can update your local version of the Django code, known as your local checkout, to get the latest changes and improvements made by Django developers. When using master, keep in mind there’s no guarantee things won’t be broken at any given moment.

Launch the Python interactive shell with manage.py shell and verify that the new field was added properly by importing the model and selecting from the table (e.g., MyModel.objects.all()[:5]). If you updated the database correctly, the statement should work without errors. Then on the production server perform these steps: Start your database’s interactive shell. Execute the ALTER TABLE statement you used in step 3 of the development environment steps. Add the field to your model. If you’re using source-code revision control and you checked in your change in development environment step 1, now is the time to update the code (e.g., svn update, with Subversion) on the production server. Restart the Web server for the code changes to take effect. For example, let’s walk through what we’d do if we added a num_pages field to the Book model from Chapter 5. First, we’d alter the model in our development environment to look like this: class Book(models.Model): title = models.CharField(max_length=100) authors = models.ManyToManyField(Author) publisher = models.ForeignKey(Publisher) publication_date = models.DateField() num_pages = models.IntegerField(blank=True, null=True) def __unicode__(self): return self.title (Note: Read the section “Making Fields Optional” in Chapter 6, plus the sidebar “Adding NOT NULL Columns” below for important details on why we included blank=True and null=True.)

 

pages: 193 words: 31,998

Java: The Good Parts by Jim Waldo

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en.wikipedia.org, remote working, revision control, web application

‡ LISP programmers are always happy to tell you just how much better LISP was than anything before or since, how much better it was as a development language, and how all the advances that have occurred since then are just attempts at recreating what they had 30 years ago. Even if they are right, they need to let it go. IDEs | 165 This is not to say that everything is perfect with these tools. I have had, well…interesting experiences with the way IDEs interface with revision control systems. The view of what code is appropriate may strike some as a bit fascistic. And the user interface— well, let’s just say this is the sort of interface that could only have been produced by programmers on an open source project. Everything can be configured and changed, which is the good news. And most everything needs to be configured and changed, which is the bad news. Still, these are great tools, and their rapid evolution and improvement over time is a testament to the open source development model they have adopted.

 

pages: 1,201 words: 233,519

Coders at Work by Peter Seibel

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Ada Lovelace, bioinformatics, cloud computing, Conway's Game of Life, domain-specific language, fault tolerance, Fermat's Last Theorem, Firefox, George Gilder, glass ceiling, HyperCard, information retrieval, loose coupling, Menlo Park, Metcalfe's law, premature optimization, publish or perish, random walk, revision control, Richard Stallman, rolodex, Saturday Night Live, side project, slashdot, speech recognition, the scientific method, Therac-25, Turing complete, Turing machine, Turing test, type inference, Valgrind, web application

Most of software development goes on in your head anyway. I think having worked with that simpler system imposes a kind of disciplined way of thinking. If you haven't got a directory system and you have to put all the files in one directory, you have to be fairly disciplined. If you haven't got a revision control system, you have to be fairly disciplined. Given that you apply that discipline to what you're doing it doesn't seem to me to be any better to have hierarchical file systems and revision control. They don't solve the fundamental problem of solving your problem. They probably make it easier for groups of people to work together. For individuals I don't see any difference. Also, I think today we're kind of overburdened by choice. I mean, I just had Fortran. I don't think we even had shell scripts.

 

pages: 282 words: 79,176

Pro Git by Scott Chacon

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continuous integration, Debian, distributed revision control, GnuPG, pull request, revision control

Local Version Control Systems Many people’s version-control method of choice is to copy files into another directory (perhaps a time-stamped directory, if they’re clever). This approach is very common because it is so simple, but it is also incredibly error prone. It is easy to forget which directory you’re in and accidentally write to the wrong file or copy over files you don’t mean to. To deal with this issue, programmers long ago developed local VCSs that had a simple database that kept all the changes to files under revision control (see Figure 1–1). Figure 1–1. Local version control diagram. One of the more popular VCS tools was a system called rcs, which is still distributed with many computers today. Even the popular Mac OS X operating system includes the rcs command when you install the Developer Tools. This tool basically works by keeping patch sets (that is, the differences between files) from one change to another in a special format on disk; it can then re-create what any file looked like at any point in time by adding up all the patches.

 

pages: 315 words: 85,791

Technical Blogging: Turn Your Expertise Into a Remarkable Online Presence by Antonio Cangiano

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Albert Einstein, anti-pattern, bitcoin, bounce rate, cloud computing, en.wikipedia.org, John Gruber, Lean Startup, Network effects, revision control, search engine result page, slashdot, software as a service, web application

Many of these generators are simple, small, and written in scripting languages such as Python, Perl, and Ruby; so if you are familiar with these languages, you’ll be able to easily extend them to customize their behavior. This process is arguably much simpler than learning how to customize a large system such as WordPress. Other points in favor of Jekyll and similar static generators are the ability to store your blog under revision control through tools like Git or Subversion and the simplicity of being able to deploying the output site pretty much anywhere, as well as its positive performance implications. In fact, since your blog ends up being a static site, its performance should be very good—even on commodity hardware. The major disadvantage is that you are on your own. There are very few premade add-ons that aid you in accomplishing even a small percentage of what you can do with software like WordPress.

 

Remix: Making Art and Commerce Thrive in the Hybrid Economy by Lawrence Lessig

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Amazon Web Services, Andrew Keen, Benjamin Mako Hill, Berlin Wall, Bernie Sanders, Brewster Kahle, Cass Sunstein, collaborative editing, disintermediation, don't be evil, Erik Brynjolfsson, Internet Archive, invisible hand, Jeff Bezos, jimmy wales, Kevin Kelly, late fees, Netflix Prize, Network effects, new economy, optical character recognition, PageRank, recommendation engine, revision control, Richard Stallman, Ronald Coase, Saturday Night Live, SETI@home, sharing economy, Silicon Valley, Skype, slashdot, Steve Jobs, The Nature of the Firm, thinkpad, transaction costs, VA Linux

This one was by far the easiest.) The company hopes that the ease and quality of its distribution (not to mention its price) will drive many more individual computer users to use Ubuntu Linux. Canonical aims to profit from the community-driven and community-developed Ubuntu. Its vision is inspired by Shuttleworth, who says he has been “fascinated by this phenomenon of collaboration around a common digital good with strong revision control.”7 That collaboration is done through a community. Canonical intends to “differentiate ourselves by having the best community. Being the easiest to work with, being the group where sensible things happen first and happen fastest.” “Community,” Shuttleworth said to me, “is the absolute essence of what we do.” “Thousands” now collaborate in the Canonical project. To make this collaboration work, as Shuttleworth describes, at least three things must be true about the community.

 

Programming Android by Zigurd Mednieks, Laird Dornin, G. Blake Meike, Masumi Nakamura

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anti-pattern, business process, conceptual framework, create, read, update, delete, database schema, Debian, domain-specific language, en.wikipedia.org, fault tolerance, Google Earth, interchangeable parts, iterative process, loose coupling, MVC pattern, revision control, RFID, web application

Android tools preprocess these definitions, and turn them into highly optimized representations and the Java source through which application code refers to them. The autogenerated code, along with code created for AIDL objects (see AIDL and Remote Procedure Calls ), is put into the gen directory. The compiler compiles the code from both directories to produce the contents of bin. The full structure of a project was described in detail in Chapter 3. Note When you add your project to a revision control system like Git, Subversion, or Perforce, be sure to exclude the bin and gen directories! Your application source code goes in the src directory. As noted in Chapter 2, you should put all your code into a package whose name is derived from the domain name of the owner of the code. Suppose, for instance, that you are a developer at large, doing business as awesome-android.net. You are under contract to develop a weather-prediction application for voracious-carrier.com.

 

pages: 655 words: 141,257

Programming Android: Java Programming for the New Generation of Mobile Devices by Zigurd Mednieks, Laird Dornin, G. Blake Meike, Masumi Nakamura

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anti-pattern, business process, conceptual framework, create, read, update, delete, database schema, Debian, domain-specific language, en.wikipedia.org, fault tolerance, Google Earth, interchangeable parts, iterative process, loose coupling, MVC pattern, revision control, RFID, web application

The autogenerated code, along with code created for AIDL objects (see AIDL and Remote Procedure Calls ), is put into the gen directory. The compiler compiles the code from both directories to produce the contents of bin. We’ll see in a minute how the res directory is particularly important for making application data accessible using a Context object. Tip When you add your project to a revision control system like Git, Subversion, or Perforce, be sure to exclude the bin and gen directories! Organizing Java Source Your application source code goes in the src directory. As noted in Chapter 2, you should put all your code into a package whose name is derived from the domain name of the owner of the code. Suppose, for instance, that you are a developer at large, doing business as awesome-android.net.

 

pages: 1,025 words: 150,187

ZeroMQ by Pieter Hintjens

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anti-pattern, carbon footprint, cloud computing, Debian, distributed revision control, domain-specific language, factory automation, fault tolerance, fear of failure, finite state, Internet of things, iterative process, premature optimization, profit motive, pull request, revision control, RFC: Request For Comment, Richard Stallman, Skype, smart transportation, software patent, Steve Jobs, Valgrind, WebSocket

Ultimately, we’re economic creatures, and the sense that “we own this, and our work can never be used against us” makes it much easier for people to invest in an open source project like ØMQ. And it can’t be just a feeling, it has to be real. There are a number of aspects to making collective ownership work; we’ll see these one by one as we go through C4. Preliminaries The project SHALL use the Git distributed revision control system. Git has its faults. Its command-line API is horribly inconsistent, and it has a complex, messy internal model that it shoves in your face at the slightest provocation. But despite doing its best to make its users feel stupid, Git does its job really, really well. More pragmatically, I’ve found that if you stay away from certain areas (branches!), people learn Git rapidly and don’t make many mistakes.

 

pages: 752 words: 131,533

Python for Data Analysis by Wes McKinney

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backtesting, cognitive dissonance, crowdsourcing, Debian, Firefox, Google Chrome, index card, random walk, recommendation engine, revision control, sentiment analysis, Sharpe ratio, side project, sorting algorithm, statistical model, type inference

In [5]: code Out[5]: output At times, for clarity, multiple code examples will be shown side by side. These should be read left to right and executed separately. In [5]: code In [6]: code2 Out[5]: output Out[6]: output2 Data for Examples Data sets for the examples in each chapter are hosted in a repository on GitHub: http://github.com/pydata/pydata-book. You can download this data either by using the git revision control command-line program or by downloading a zip file of the repository from the website. I have made every effort to ensure that it contains everything necessary to reproduce the examples, but I may have made some mistakes or omissions. If so, please send me an e-mail: wesmckinn@gmail.com. Import Conventions The Python community has adopted a number of naming conventions for commonly-used modules: import numpy as np import pandas as pd import matplotlib.pyplot as plt This means that when you see np.arange, this is a reference to the arange function in NumPy.

 

pages: 792 words: 48,468

Tcl/Tk, Second Edition: A Developer's Guide by Clif Flynt

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hypertext link, revision control, Silicon Valley, web application

This is the equivalent of having the MS-DOS .bat file interpreter and command.com functionality available at the command line. Experienced users use this feature to write small programs from the command line to accomplish simple tasks. For instance, suppose you give a friend a set of source code, and a few weeks later he returns it with a bunch of tweaks and fixes. You may want to go through all the source code to see what has been changed in each file before you commit the changes to your revision control system. Using a UNIX-style shell, you can compare all files in one directory to files with the same name in another directory and place the results in a file with a DIF suffix. The commands at the Bourne, Korn, or Bash shell prompt are as follows: $ for i in *.c do diff $i ../otherDir/$i >$i.DIF done You can use tclsh to gain this power in the Windows and Macintosh worlds. The code to accomplish the same task under Windows using a tclsh shell is % foreach i [glob *.c]{ fc $i ..

 

HBase: The Definitive Guide by Lars George

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Amazon Web Services, bioinformatics, create, read, update, delete, Debian, distributed revision control, domain-specific language, en.wikipedia.org, fault tolerance, Firefox, Google Earth, place-making, revision control, smart grid, web application

Consider the code a petri dish for your own experiments. Building the code requires a few auxiliary command-line tools: Java HBase is written in Java, so you do need to have Java set up for it to work. Java has the details on how this affects the installation. For the examples, you also need Java on the workstation you are using to run them. Git The repository is hosted by GitHub, an online service that supports Git—a distributed revision control system, created originally for the Linux kernel development.[3] There are many binary packages that can be used on all major operating systems to install the Git command-line tools required. Alternatively, you can download a static snapshot of the entire archive using the GitHub download link. Maven The build system for the book’s repository is Apache Maven.[4] It uses the so-called Project Object Model (POM) to describe what is needed to build a software project.

 

pages: 834 words: 180,700

The Architecture of Open Source Applications by Amy Brown, Greg Wilson

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8-hour work day, anti-pattern, bioinformatics, c2.com, cloud computing, collaborative editing, combinatorial explosion, computer vision, continuous integration, create, read, update, delete, Debian, domain-specific language, en.wikipedia.org, fault tolerance, finite state, Firefox, friendly fire, linked data, load shedding, locality of reference, loose coupling, Mars Rover, MVC pattern, premature optimization, recommendation engine, revision control, side project, Skype, slashdot, social web, speech recognition, the scientific method, The Wisdom of Crowds, web application, WebSocket

Changes are published by issuing a commit command, which will save the changes from the working directory to the repository. 12.1.1. Centralized Version Control The first version control system was the Source Code Control System, SCCS, first described in 1975. It was mostly a way of saving deltas to single files that was more efficient than just keeping around copies, and didn't help with publishing these changes to others. It was followed in 1982 by the Revision Control System, RCS, which was a more evolved and free alternative to SCCS (and which is still being maintained by the GNU project). After RCS came CVS, the Concurrent Versioning System, first released in 1986 as a set of scripts to manipulate RCS revision files in groups. The big innovation in CVS is the notion that multiple users can edit simultaneously, with merges being done after the fact (concurrent edits).

 

Evidence-Based Technical Analysis: Applying the Scientific Method and Statistical Inference to Trading Signals by David Aronson

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Albert Einstein, Andrew Wiles, asset allocation, availability heuristic, backtesting, Black Swan, capital asset pricing model, cognitive dissonance, compound rate of return, Daniel Kahneman / Amos Tversky, distributed generation, Elliott wave, en.wikipedia.org, feminist movement, hindsight bias, index fund, invention of the telescope, invisible hand, Long Term Capital Management, mental accounting, meta analysis, meta-analysis, p-value, pattern recognition, Ponzi scheme, price anchoring, price stability, quantitative trading / quantitative finance, Ralph Nelson Elliott, random walk, retrograde motion, revision control, risk tolerance, risk-adjusted returns, riskless arbitrage, Robert Shiller, Robert Shiller, Sharpe ratio, short selling, statistical model, systematic trading, the scientific method, transfer pricing, unbiased observer, yield curve, Yogi Berra

Look-ahead bias can also occur if a rule uses data series that are reported with a lag, such as mutual fund cash statistics, or that are subject Case Study Results and the Future of TA 449 to revisions, such as government economic statistics. When this is the case, lagged values must be used that take into account reporting delays or revisions. The case study avoided look-ahead bias by assuming entries and exits on the open price of the day following a position-reversal signal. Moreover, none of data series used were subject to reporting lags or revisions. Controlled for Data-Mining Bias. Few rule studies in popular TA apply significance tests of any sort. Thus, they do not address the possibility that rule profits may be due to ordinary sampling error. This is a serious omission, which is easily corrected by applying ordinary hypothesis tests. However, ordinary tests of significance are only appropriate when only one rule has been back tested. When many rules have been tested and a best is selected, the ordinary hypothesis test will make the best rule appear more statistically significant than it really is (false rejection of the null hypothesis).