Practical git for developers
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A practical step-by-step guide to Git, taking you through each phase of a project and explaining the use of Git at each step of the development process. Expect lots of how-to, but also some how-not-to, to avoid going down the wrong path.
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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 "[email protected]" $ 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;