GIT INTRODUCTION
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Git is a distributed version control system that was created by Linus Torvalds in 2005 to manage the Linux kernel source code. It allows developers to work simultaneously and maintain a complete history of their work. Git uses a distributed model where every developer has a full copy of the code repository, enabling them to work offline and collaborate asynchronously by integrating changes from any repository. Developers commit changes to their local repository and synchronize changes by pushing to or pulling from remote repositories.
GIT INTRODUCTION
- 1. GIT By K. Ravi Rohith
- 2. CONTENTS • INTRODUCTION TO GIT • HISTORY OF GIT • VERSION CONTROL SYSTEM • GETTING STARTED TO GIT • GIT UTILITY COMMANDS • BRANCHING • MERGING • REBASE • SUMMARY
- 3. INTRO TO GIT • GIT is a Distributed Version Control System. • It is a content addressable file system, used to track directory trees. • It handles all the things like merging of source code and maintaining versions. • GIT is optimized for Complex Merges and Fast. • It follows Trunk Base Development. • It allows for code collaboration with anyone online.
- 4. GIT HISTORY • Linus uses BitKeeper to manage Linux code • In 2005, BitKeeper suddenly became unavailable. • Linus decided to create a tool with Distributed Source Management System. • Linus Torvalds developed GIT in June 2005.
- 5. TERMINOLOGY • DIRECTORY : A folder is used for storing multiple files. • REPOSITORY : A collection of all the files and their history organized in folders, branches, tags. • CLONE : Act of copying a repository from a remote server. • BRANCH : It is a pointer to a commit(save the files). • MERGE : Combination of one or more branches into the current branch. • ORIGIN : The default name of the remote repository. • MASTER : It is just another branch, but is the default one which gets created. • STAGE FILES : These are the files we have told GIT that are ready to committed. • SNAPSHOT : In general is just the "entity" that git uses to store its data. • INTEGRATORS : It can review and bring changes to reference code asynchronously to central repository.
- 6. VERSION CONTROL SYSTEM • Version Control System (VCS) is a software that helps software developers to work together and maintain a complete history of their work. • Version Control, also known as Revision Control or Source Control. Functions of a Version Control System : • Allows developers to work simultaneously. • Maintains a history of every version. • Does not allow overwriting each other’s changes. Following are the types of Version Control System : • Centralized version control system (CVCS). • Distributed/Decentralized version control system (DVCS).
- 7. CENTRALIZED VERSION CONTROL SYSTEM • Centralized version control system (CVCS) uses a central server to store all files and enables team collaboration. • “Committing” a change simply means recording the change in the central system and Other programmers can then see this change. • They can also pull down the change, and the version control tool will automatically update the contents of any files that were changed. • It is a Client-Server approach.
- 8. CENTRALIZED VERSION CONTROL WORKFLOW When you’re working with a Centralized Version Control System, your workflow for adding a new feature or fixing a bug in your project will usually look something like this: • Pull down any changes other people have made from the central server. • Make your changes, and make sure they work properly. • Commit your changes to the central server, so other programmers can see them.
- 9. DISADVANTAGES OF CENTRALIZED VERSION CONTROL • Merging of files or code is difficult. • A single point of failure i.e., failure of the central server. • Remote Server commits slow while transferring data. • Unsolicited changes that may break your project.
- 10. DISTURBUTED VERSION CONTROL SYSTEM • Distributed Version Control System (DVCS) is a form of version control that allows software developers to work on a given project without requiring them to share a common network. • Distributed version control takes a peer to peer approach. • It synchronizes repositories by exchanging patches (sets of changes) from peer to peer.
- 11. Advantages of Distributed Version Control System • Don’t require any common network • DVCS is fast because it not rely on central server. • In Implicit Backup, data present on any client side mirrors the repository, hence it can be used in the event of a crash or disk corruption. • Security is more. It uses a common cryptographic hash function called secure hash function. • Easy to create branches because DVCS is branch management system.
- 12. DVCS TERMINOLOGIES • Local Repository – it is a private workplace • Working Directory – the place where files are checked out. • Blob – stands for Binary Large Object. Each version of a file is represented by blob. • Tree - Tree is an object, which represents a directory. It holds blobs as well as other sub-directories. • Revision - Revision represents the version of the source code. Revisions in Git are represented by commits. • Tags – It assigns a meaningful name with a specific version in the repository. It is immutable.
- 13. GETTING STARTED Git is a version control system for tracking changes in computer files and coordinating work on those files among multiple people. • Three trees of Git – The HEAD • last commit snapshot, next parent – Index • Proposed next commit snapshot – Working directory • Sandbox
- 14. WORKFLOW OF GIT • Init a repo – To initialize the repository in GIT : Git init • Edit files • Stage the changes • Review your changes • Commit the changes
- 15. Getting Started • A basic workflow – Edit files – Stage the changes – Review your changes – Commit the changes Use your favorite editor 15
- 16. Getting Started • A basic workflow – Edit files – Stage the changes – Review your changes – Commit the changes • Git add filename 16
- 17. • A basic workflow – Edit files – Stage the changes – Review your changes – Commit the changes • Git status 17 Getting Started
- 18. Getting Started • A basic workflow – Edit files – Stage the changes – Review your changes – Commit the changes Git commit 18
- 19. Other GIT Utility commands • git gc – garbage collector (run it when the /.git/ directory takes too much space). • git stash – save/restore the state of the working copy and index. • git clean – clean the working tree. • git bisect – locating which commit introduced a bug. • git cherry-pick – merging a single commit. • git revert – canceling a previous commit
- 20. BRANCHING • It is a pointer to a commit(save the files). • The default branch name in Git is master. • ‘git branch’ command used for create, rename, list and delete files. 20
- 21. USAGE • git branch – List all of the branches in your repository. • git branch <branch> – To create a new branch called <branch>. • git branch -d <branch> – To delete the branch. • git branch -m <branch> – To rename the current branch. • git branch –merged – To display all branches that are already merged. • git branch –a –color – it will be shown in appropriate colors to all branches. git branch -a --color
- 22. USAGE • Git checkout – lets you navigate between the branches created by git branch.
- 23. MERGE • Combining one ore more branches into the current branch. • Allows changes from other branches to be integrated into the current work history • Merge only changes the workspace. • If we commit in branch, other branches not affected Features – Fast Forward Merge – 3 way Merge 23
- 24. 24 MERGING EXAMPLE Adding new branch to experiment
- 25. 25 Committing the branch to repository Finally it navigates all the branches in directory.
- 26. MERGING - CONFLICTS • When merging, if there are conflicts - need to solve them. • After solving, need to “add” the changes and commit the merged workspace.
- 27. Working with remote Local file system • Pros – Simple – Support existing access control – NFS enabled • Cons – Public share is difficult to set up – Slow on top of NFS 27
- 28. Working with remote GIT • Pros – Fastest protocol – Allow public anonymous access • Cons – Lack of authentication – Difficult to set up 28
- 29. Working With Remote • Remote branching – Branch on remote are different from local branch – Git fetch origin to get remote changes – Git pull origin try to fetch remote changes and merge it onto current branch. – Git push means share your work done on branch to remote 29
- 30. REBASE • Instead of merging, replays set of changes on top of another branch • Affects the “rebased” branch only • Very useful to remove history clutter • Simple rule, use locally only and for branches which you will never share
- 31. SUMMARY • Git is complex, but flexible and powerful. • Git supports distributed teams very well. • Due to it’s flexibility, every team needs to decide on the workflow which works best for it.
- 32. THANK YOU