Practical git for developers

Practical git for developers

• 1.
  Practical git fordevelopers (aka 'Git for beginners') Wim Godden Cu.be Solutions @wimgtr
• 2.
  Who am I? Wim Godden (@wimgtr)
• 3.
  Where I'm from
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  Where I'm from
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  Where I'm from
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  Where I'm from
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  Where I'm from
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  Where I'm from
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  My town
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  My town
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  Belgium – thetraffic
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  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
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  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...
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  What is git? Git is a file system with a Version Control System on top of it
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  What is git? Git is a distributed file system with a Version Control System on top of it
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  (Almost) everything islocal 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
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  (Almost) everything isimmutable Immutable = doesn't change Once placed in git, it stays there Even if you delete files
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  Differences with SVN SVNkeeps 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
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  Differences with SVN SVNis 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)
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  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 …
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  Create a repo $git init $ tree .git .git/ ├── branches ├── config ├── description ├── HEAD ├── info │   └── exclude ├── objects │   ├── info │   └── pack └── refs ├── heads └── tags
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  .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
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  git clone Creates arepository from an existing repository git clone https://someplace.com/repo.git <somefolder> Original repository is called 'origin' → This is called a 'remote'
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  Git flow Working directory Stagingarea Repository Remote(s) Add Commit Push
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  git status Simple command Explainsin clear language what's going on Use it, use it, use it, ...
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  Git flow Working directory Stagingarea Repository Remote(s) Add Commit Push
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  git add Add filein 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
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  git reset Unstage changes Revertto older commit version Beware : dangerous command !
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  Remove files fromrepository 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>
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  Git flow Working directory Stagingarea Repository Remote(s) Add Commit Push
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  git commit Creates anew 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
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  git log Shows eachcommit with SHA1 hash → hash can be used with other commands -p gives a diff view
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  git diff No params: default diff output git diff --staged : diff with what's been staged
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  Clone, add, commitand 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 gitpush → Send locally commited changes to the remote repository git fetch/pull → Retrieve changes from the remote repository
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  Fetch, merge andpull 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
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  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
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  Branches Branches are separatefull-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>
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  Merging changes ina 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
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  Conflicting change git merge<branchname> → conflict git status → shows conflicted files Resolve conflict git commit -a → tells git conflict was resolved
• 44.
  Contributing to aGithub 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
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  Creating a fork
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  Creating a fork Willcreate 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 ;-)
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  Next : createa 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
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  Next : add/changecode 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
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  Next : createa 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”
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  Next : mergingthe 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 ;-)
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  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
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  Questions ?
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  Questions ?
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  Thanks ! @wimgtr [email protected]