Teaching git and GitHub

Slides for a 1.5-2 hour git/GitHub tutorial. In the tutorial, I walk students through different git concepts and have them practice git commands in a terminal, and then at the end I walk through interactions with remote repositories on GitHub.

Transcript

1. Introduction to version control with git and GitHub Stephanie Douglas
2. Why worry about version control?
3. Avoid this mess Folder is “old drafts” - this doesn't even include submitted or revised versions!
4. Version control: one file with a hidden record of every change
5. How to learn git
6. Repository – contains files for your project
7. Set up git and create a repository $ git config --global user.name “name” $ git config --global user.email “address@gmail” $ cd code/python/ (or other folder of your choice)
8. Set up git and create a repository
9. Set up git and create a repository
10. Copy the repo onto your computer $ git clone https://github.com/yourname/demo_repo.git $ cd demo_repo $ git status
11. Commits – preserve the state of a tracked file at a particular time
12. Commits track changes over time
13. Anatomy of a Commit Modify a file (or files)
14. Anatomy of a Commit Modify a file (or files) Stage file(s)
15. Anatomy of a Commit Modify a file (or files) Stage file(s) Commit your changes
16. Add a new file with some text Modify a file (or files)
17. $ git add newfile.txt Modify a file (or files) Stage file(s)
18. $ git commit -m “first commit :)” Modify a file (or files) Stage file(s) Commit your changes
19. Once a file has been staged and committed, git will always track it Modify a file (or files) Stage file(s) Commit your changes
20. Edit your README file Modify a file (or files) $ git status $ git diff README
21. Now commit it Modify a file (or files) Stage file(s) Commit your changes $ git add README $ git commit -m “describe your changes”
22. Branches – multiple versions of the same repository master
23. Branches – multiple versions of the same repository master fix_a_bug
24. Develop while preserving working code master (working) fix_a_bug (changing/testing)
25. Fast-forward merge - nothing changed on original branch
26. Show branches master $ git branch
27. Create a new branch master fix_a_bug $ git branch branch_name $ git checkout branch_name
28. fix_a_bug Edit one of your files and commit your changes master $ git add filename $ git commit -m “describe changes”
29. Merge your changes into master and delete the branch $ git checkout master $ git diff branch_name $ git merge branch_name $ git branch -d branch_name
30. Fast-forward merge - nothing changed on original branch
31. Cheat Sheet bit.ly/github_cheats https://training.github.com/kit/downloads/ github-git-cheat-sheet.pdf
32. Merging two divergent branches
33. Recursive merge – no conflicting edits, git combines the changes
34. Merge conflict - git marks conflicting edits, user fixes and commits
35. Make a new branch, edit your README, and commit
36. Switch back to master. Edit your other file, and commit
37. Recursive merge – no conflicting edits, git combines the changes
38. Make a new branch, make and commit some edits
39. Switch back to master. Edit the same lines, but make different changes
40. Now try to merge your new branch into master
41. Merge conflict! Open the file again, look for lines like this: <<<<<<< HEAD the text from master ======= the text from your branch >>>>>>> branch_name
42. Select the version you want, delete the rest. Close, add, and commit. <<<<<<< HEAD the text from master ======= the text from your branch >>>>>>> branch_name
43. Relationships between repositories GitHub (or other server) Remote Repository
44. Clone – copy the repo to your computer GitHub (or other server) Remote Repository Clone Ann's Computer Local Copy
45. Clone – copy the repo to your computer GitHub (or other server) origin Ann's Computer local directory
46. Push - send local changes of one branch to remote repo master origin/master
47. Adding changes to github Open a branch, make and commit an edit. Then $ git push origin branch_name Now merge that branch into master, and then $ git push origin master
48. Fetch: get changes from remote repo, but don't merge them master master origin/master
49. Edit a file on GitHub, then commit your changes
50. Fetch changes from the remote repository master master origin/master $ git fetch origin $ git branch -a $ git checkout master $ git diff origin/master
51. Then merge the changes master master origin/master $ git merge origin/master
52. Pull: get changes on remote branch and merge them automatically Local Repository Remote Repository
53. Pull will fail if you have conflicting changes, and it's a pain to sort out Local Repository Remote Repository
54. When in doubt, always fetch and merge! master master origin/master
55. Fork – make your own version of someone else's repository GitHub (or other server) Original Repository GitHub (or other server) Fork
56. Go to https://github.com/stephtdouglas/demo_fork
57. Clone – copy a remote repository onto your computer GitHub (or other server) Original Repository GitHub (or other server) Fork Bob's Computer Clone of fork
58. Clone the fork onto your computer $ git clone https://github.com/yourname/demo_fork.git
59. Remotes – links to remote repositories GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
60. Edit anything on local repo and the forked repo (origin) GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
61. Only fetch/pull from original repo (upstream); don't push GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
62. Add a link to my original repository GitHub (or other server) upstream $ git remote add upstream https://github.com/stephtdouglas/demo_fork.git OR (only if you set up ssh keys) $ git remote add upstream git@github.com:stephtdouglas/demo_fork.git $ git remote -v
63. Pull request – ask for changes from a fork to be added to original repo GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
64. Add yourname.txt to your local copy of demo_fork, commit and push it GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
65. Open a pull request from your fork GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo
66. Base – my original repository Compare – your fork
67. Fetch and merge changes from my repository GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo $ git fetch upstream $ git diff upstream/master $ git merge upstream/master
68. Learning more Start at GitHub's help pages - they're very helpful. They have a bootcamp and a cheat sheet https://help.github.com/ https://help.github.com/categories/bootcamp/ https://training.github.com/kit/downloads/github-git-cheat-sheet.pdf How to clone, fetch, merge, and pull: https://help.github.com/articles/fetching-a-remote/
69. Fetch and merge changes from my repository GitHub (or other server) upstream GitHub (or other server) origin Bob's Computer local repo $ git fetch upstream $ git diff upstream/master $ git merge upstream/master
70. Learning more The Git docs are also useful. See their references pages for details and examples of commands. http://git-scm.com/docs Pretty much everything you could ever want to know about Git can be found in the Git Book: http://git-scm.com/book/en/v2 Here are different workflows for collaborating: https://www.atlassian.com/git/tutorials/comparing- workflows/centralized-workflow
71. Which remote host? GitHub • Public repos are free • Link to .edu email, get 5 free private repos • Very popular, most open source projects are there BitBucket • Private repos are free • Pay for public and shared repos • Also works with mercurial (not on the same repo, though) You can use both (I do)
72. git for publications Overleaf (formerly WriteLaTeX) has basic git integration in beta for unprotected projects. Sign up at https://www.overleaf.com/signup?ref=2a936e948ade Authorea also has git integration, using GitHub itself rather than their own server