git- Most Of The Things About a Trending DVCS
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This document provides an overview of Git and version control systems. It discusses key concepts such as centralized (CVCS) and distributed (DVCS) version control systems. Git is introduced as a popular DVCS, along with advantages like offline commits and ability to refer to others' local repositories. Basic Git commands and workflow are explained, including initializing a repository, adding/committing files, branching, merging, and resolving conflicts. The document concludes with notes on collaborative development using remote repositories on services like GitHub.
![COLLABORATIVE DEVELOPMENT (CONTD.)
▸ create your own branch to work on the remote repository
branch.
▸ git branch --track [new-local-branch] [remote-
branch]
▸ get updates from remote branch.
▸ git fetch origin
▸ Now update your local “master” and branches with the
updates.
▸ git pull origin <master/branch_name>](https://image.slidesharecdn.com/git-presentation-iit-151120161604-lva1-app6891/85/git-Most-Of-The-Things-About-a-Trending-DVCS-21-320.jpg)
git- Most Of The Things About a Trending DVCS
- 1. git MOST OF THE THINGS ABOUT A TRENDING DVCS ISURU WIMALASUNDERA
- 2. VERSION CONTROL ▸ version control , revision control & source control are referring to the same… ▸ version control systems are to manage the changes done on software programs, documents and any collection of information . ▸ Centralized version control systems (CVCS) and Distributed version (DVCS) ▸ CVCS - CVS , Subversion (SVN) , Perforce
- 3. DVCS … ▸ Mercurial, Git and Bazaar ▸ Has a central repository But …. ▸ Do not rely on that central repo to store all the versions of a project. ▸ every developer “clones” a copy of the central repository. ▸ The “clone” copy has the full history and all meta-data of the original. ▸ “pull” to get new change, “push” to add new change.
- 4. ADVANTAGES & DISADVANTAGES OF DVCS ▸ pushing and pulling changes are fast , as it is not accessing a remote server but your own hard drive. ▸ offline commit of changes. ▸ can commit a set of changes without affecting others. ▸ Others can refer ones local repository and check changes. ▸ If the main repo is very large and has long history it can consume large amount of space and lot of time to download.
- 5. "I'M AN EGOTISTICAL BASTARD, AND I NAME ALL MY PROJECTS AFTER MYSELF. FIRST 'LINUX', NOW 'GIT'." Linus Torvalds
- 6. GIT - HOW IT ALL BEGINS ▸ founded by Linus Torvalds and the Linux Kernel team ▸ From 1991 to 2002 modifications to linux kernel was kept in file system as patches. ▸ Linux moved to BitKeeper a proprietary DVCS in 2002. ▸ BitKeeper revoked the free usage for linux team, and Linux Kernel team started writing their own DVCS. ▸ so came the git , and the rest is history….
- 8. INSTALLING GIT … ▸ Installing git - enough references are there in Google ▸ Installation methods are platform specific.
- 9. UNDERSTANDING GIT CORE ▸ git is a content-addressable filesystem, bit like Unix. ▸ means that at the core of Git is a simple key-value data store. ▸ The key is a 40-character checksum hash. ▸ value can be different types of git objects. ▸ git Object types ▸ Tree Objects, Blob Objects, Commit Objects & Tag Objects
- 10. UNDERSTANDING GIT CORE (CONTD.) ▸ Tree Objects represent the repository. (similar to a folder/ directory in a file system) ▸ Blob objects are the leafs , any file in the repository. (similar to files in a file system) ▸ Commit Objects the functional object of repository current status. ▸ Tag Objects categorise a commit object by naming it. ▸ A good reference ▸ https://git-scm.com/book/en/ v2/Git-Internals-Git-Objects
- 11. CREATE YOUR GIT REPOSITORY ▸ Configure your git ▸ git config --global user.name "Your Name" ▸ git config --global user.email you@example.com ▸ Go in to your project and initialise a git repository. ▸ git init ▸ Add all the project directories and files to repository. ▸ git add . ▸ Now Commit all the added directories and files to git. ▸ git commit -m “<commit-message>”
- 12. WHERE IS THE GIT REPOSITORY ? ▸ Its there along with the project files, look for a hidden file “.git” , a single folder , in the project root. ▸ The git repository contains ▸ Head file ▸ Objects ▸ branches ▸ logs and many more
- 13. WHAT HAPPENS WHEN YOU ADD TO GIT ? ▸ Git Three Tree
- 14. USEFUL GIT COMMANDS AT THIS STAGE ▸ git log - shows a log of all commits starting from HEAD back to the initial commit. ▸ git status - shows which files have changed between the current project state and HEAD. ▸ git diff - shows the diff between HEAD and the current project state. ▸ git mv and git rm - mark files to be moved (rename) and removed, respectively, much like git add.
- 15. HOW DOES GIT COMMIT WORKS ? ▸ git commit is the current status of repository. ▸ Represented by the Commit Object, the commit object contains follows. ▸ The set of files currently available (changed/unchanged). ▸ Reference to parent commit (the SHA1 key of parent commit). ▸ The SHA1 name. ▸ git add will add files to the commit object, current versions of changed files, previous version of unchanged / un- added files.
- 16. HOW DOES GIT COMMIT WORKS ? (CONTD.) ▸ git commit will submit the commit object, a commit is a snapshot of the repository. ▸ Now the “new commit object” is the current status of the git repository.
- 17. GIT BRANCHING ▸ Manage drastic changes, new features. ▸ Manage a different copy of the “master” within same repository. which means another commit object. ▸ create a branch. ▸ git branch <name> ▸ Point HEAD to the new branch. ▸ git checkout <branch_name> ▸ Better to manage “trunk” & “branch” practice.
- 18. GIT MERGING ▸ If we are merging the branch to master, set HEAD to master. And then merge ▸ git checkout master ▸ git merge <branch_name> ▸ Then do a new git commit.
- 19. CONFLICT RESOLUTION ▸ At the point of merging , if master repository has changed from the ancestor commit, then conflicts can happen at the point of merging. ▸ Git will add conflict messages at exact points. ▸ Manually edit those locations and commit.
- 20. COLLABORATIVE DEVELOPMENT ▸ Get someones git repository , ▸ git clone <repo_url> ▸ Create a remote repo reference named as “origin”. ▸ Then new heads will get created pointing to the header of remote repo, known as “remote heads” ▸ origin/master - for the master head ▸ origin/<branch> - for the branches
- 21. COLLABORATIVE DEVELOPMENT (CONTD.) ▸ create your own branch to work on the remote repository branch. ▸ git branch --track [new-local-branch] [remote- branch] ▸ get updates from remote branch. ▸ git fetch origin ▸ Now update your local “master” and branches with the updates. ▸ git pull origin <master/branch_name>
- 22. COLLABORATIVE DEVELOPMENT (CONTD.) ▸ To push your changes to remote repository “master” or branches. ▸ git push origin <master/branch_name>
- 24. GIT SERVICES ▸
- 25. ANY QUESTIONS ?