Practical git for developers
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This document is a comprehensive introduction to Git, detailing its features as a distributed version control system and differences from centralized systems like SVN. It explains basic Git commands, configurations, branching, and merging, along with GitHub integration for contributing to projects. The content is targeted at developers who are beginning to learn Git, with practical examples and configurations provided for effective use.
Practical git for developers
- 1. Practical git for developers (aka 'Git for beginners') Wim Godden Cu.be Solutions @wimgtr
- 2. Who am I ? Wim Godden (@wimgtr)
- 9. My town
- 10. My town
- 11. Belgium – the traffic
- 12. Who am I ? Wim Godden (@wimgtr) Founder of Cu.be Solutions (http://cu.be) Open Source developer since 1997 Developer of PHPCompatibility, OpenX, PHPConsistent, ... Speaker at Open Source conferences
- 13. Who are you ? Developers ? CVS ? SVN ? TFS ? Git ?
- 14. What is git ? Git is a file system with a Version Control System on top of it
- 15. Git's file structure Commit tree author_info parent Tree README.MD LICENSE index.php Blob datadatadata... Blob datadatadata... Blob datadatadata... 6d3af... 8a3ea... 901a3... 4a39c... e3231... 8a3ea... 901a3... 4a39c... e3231...
- 16. What is git ? Git is a file system with a Version Control System on top of it
- 17. What is git ? Git is a distributed file system with a Version Control System on top of it
- 18. (Almost) everything is local Clone = copy of entire repository Work offline : Perform a diff View file history Commit changes (!) Create, merge or switch branches etc. Only push/pull are not local
- 19. (Almost) everything is immutable Immutable = doesn't change Once placed in git, it stays there Even if you delete files
- 20. Differences with SVN SVN keeps diffs between versions Git keeps full snapshots Commit #1 tree author_info parent Tree README.MD Commit #2 tree author_info parent Tree README.MD index.php Commit #3 tree author_info parent Tree README.MD LICENSE index.php
- 21. Differences with SVN SVN is centralized ↔ Git is distributed An SVN commit → shared with everyone ↔ A Git commit is local SVN has revision increments ↔ Git has SHA1 hashes to identify objects (commits, trees, blobs, ...)
- 22. Basic git – config $ git config --global user.name "Wim Godden" $ git config --global user.email "wim.godden@cu.be" $ git config --global core.editor vim $ git config --global core.autocrlf input $ git config --global core.autocrlf true $ git config --global color.ui true (on Linux) (on Windows)
- 23. Basic git - .gitignore Allows you to specify files to ignore Can be specific to repository Hint : set up a global .gitignore for : thumbnail.dat desktop.ini .DS_Store Your local editor's files …
- 24. Create a repo $ git init $ tree .git .git/ ├── branches ├── config ├── description ├── HEAD ├── info │ └── exclude ├── objects │ ├── info │ └── pack └── refs ├── heads └── tags
- 25. .git directory config – Configuration file refs/heads/... - branches refs/tags/... - tags refs/remotes/... - remotes objects/... - the actual objects HEAD – the current working space, points to one of branches
- 26. git clone Creates a repository from an existing repository git clone https://someplace.com/repo.git <somefolder> Original repository is called 'origin' → This is called a 'remote'
- 27. Git flow Working directory Staging area Repository Remote(s) Add Commit Push
- 28. git status Simple command Explains in clear language what's going on Use it, use it, use it, ...
- 29. Git flow Working directory Staging area Repository Remote(s) Add Commit Push
- 30. git add Add file in current state to the staging area Can be new file Can be modification git add -A stages all git add . stages new and modified, but no deletions git add -u stages modified and deleted, but no new files
- 31. git reset Unstage changes Revert to older commit version Beware : dangerous command !
- 32. Remove files from repository 2 ways : Delete, then rm Delete the file from working directory git rm <filename> Commit Just rm git rm <filename> Commit Accidentially deleted ? → git checkout -- <filename>
- 33. Git flow Working directory Staging area Repository Remote(s) Add Commit Push
- 34. git commit Creates a new version Based on the staging area Commits on local repository only Commit #1 tree author_info parent Tree README.MD Commit #2 tree author_info parent : #1 Tree README.MD index.php Commit #3 tree author_info parent : #2 Tree README.MD LICENSE index.php HEAD
- 35. git log Shows each commit with SHA1 hash → hash can be used with other commands -p gives a diff view
- 36. git diff No params : default diff output git diff --staged : diff with what's been staged
- 37. Clone, add, commit and push C1 Remote originLocal repository C2 master C1 C2 origin/master 1 2 C1 C2 origin/master C3 master HEAD master HEAD1 2 C1 C2 master C1 C2 origin/master C3 master HEAD 3 3 C1 C2 master C3
- 38. Working with remotes git push → Send locally commited changes to the remote repository git fetch/pull → Retrieve changes from the remote repository
- 39. Fetch, merge and pull Remote originLocal repository C1 C2 origin/master 1 2 C1 C2 origin/master C3 master HEAD master HEAD 1 C1 C2 C3 master HEAD 2 3 C1 C2 master C3C2 origin/master 3
- 40. git fetch + merge vs git pull git fetch : fetches information from remote into local repository but nothing more git merge : merges changes that were fetched needs a source parameter merges TO wherever HEAD is pointing to : git merge origin/master git pull : does both at the same time
- 41. Branches Branches are separate full-blown versions of your code Default branch = master Which branches are there ? → git branch Create a new branch → git branch <branchname> Switch to branch → git checkout <branchname> Create + switch to new branch → git checkout -b <branchname> Show branch activity : git show-branch Delete a branch : git branch -d <branchname>
- 42. Merging changes in a project C1 C2 origin/master C1 C2 origin/master C3 master master C4 test LICENSE : added paragraph 1 LICENSE : added paragraph 2 C1 C2 origin/master C3 master C4 test LICENSE : added paragraph 1 + 2 Edited LICENSE C5
- 43. Conflicting change git merge <branchname> → conflict git status → shows conflicted files Resolve conflict git commit -a → tells git conflict was resolved
- 44. Contributing to a Github project Github is built on Git, so... Clone, commit, pull, merge, push are all the same But : You need to fork the project first Changes to the main repository must be requested through a pull request
- 45. Creating a fork
- 46. Creating a fork Will create a complete copy (not a clone) of the project Including master, all branches, all tags, all commits, etc. i.e. confoo/some-repo → <your_github_username>/some-repo You can do anything in it... But please don't if you intend to contribute back... Which you should ofcourse ;-)
- 47. Next : create a branch for your feature/bugfix Why ? Work on multiple features/fixes at same time Experiment without damaging your master master should always be a fully functioning, deployable version Name the branch well Don't : bugfix Do : bugfix_issue_26_fatal_error
- 48. Next : add/change code and commit Don't forget unit tests, integration tests, … Make your commit message descriptive Don't : fixed it Do : added real-time updates on dashboard Each commit should contain a single feature or bugfix → Allows project maintainers to add small blocks of code → Easier than adding 50 features/bugfixes → Easier to test
- 49. Next : create a Pull Request (PR) When you want to contribute Partial code = OK → But only if you want feedback Otherwise : Finish your code Make sure you have unit tests Be descriptive in your pull request Don't : “this will fix my issues” Do : “Added an OAuth authentication layer”
- 50. Next : merging the PR Done by a project maintainer (could be you !) Merge from the PR branch to master Again : have a clear merge message → On Github : 'Closes #56' will close Github issue and links Congratulations, you're a Github contributor ;-)
- 51. Git tools git-cola (Linux, Win, Mac) GitHub Desktop (Win, Mac) GitKraken (Linux, Win, Mac) - beta Liquid prompt Useful list : https://git.wiki.kernel.org/index.php/Interfaces,_frontends,_and_tools
- 52. Questions ?
- 53. Questions ?
Editor's Notes
- #27: git clone [email_address]:wimg/confoodemo.git
- #42: * = current brach + = commit is in the branch - = commit is in the branch as a merge
- #44: git checkout -b test edit LICENSE file git checkout master edit LICENSE file git merge test → will show conflict git status → will show unmerged path edit LICENSE file git commit -a -m&apos;conflict resolved&apos;