Thanks Paul!

1. git for the uninitiated
Paul Litwin
Fred Hutchinson Cancer Research Center
plitwin@fredhutch.org
@plitwin

2. Slides can be found here…
• http://tinyurl.com/litwin-sea-web
Litwin Git for the Unitiated 2

3. Session Itinerary
• Why distributed version control?
• git basics
• Command line git
• Using git from VS Code
• Using git from Visual Studio
• Branching and merging
• Wrap up
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4. Why distributed version control?

5. Git is a free and open source distributed
version control system designed to handle
everything from small to very large projects
with speed and efficiency
Created by Linux creator, Linus Torvalds
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6. The name git?
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“I'm an egotistical
bastard, and I name
all my projects after
myself. First Linux,
now git.”
Linus Torvalds quote from 2007

7. Centralized Version Control
One repository using a client-server model
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8. Distributed Version Control
Many repositories using peer to peer model
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9. Comparing centralized (tfs) vs distributed (git)
Attribute Centralized
TFS, SVN, PVCS
Distributed
git, Mercurial
Repositories 1 Many
Model Client-server Peer-to-peer
Speed of common
operations
Slower Fast against local repo
Redundancy of system None; single point of
failure
Redundancy built in
Offline work More difficult Easy
Merging of changes When you check
changes in
When you sync changes
(push/pull)
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10. git Basics

11. git Basics: Getting git
• Download from: https://git-scm.com/
• Configure
– git config --global user.name “your name”
– git config --global user.email “email address”
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12. git Basics: How it works
Working
Directory
stage
Staging
Area
commit
git repo
modified staged committed
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13. Command line git

14. Using Command Line
• Windows
– use command prompt
– you may need to add git to the path (find git.exe and
add this folder to the system path)
• Control Panel|(System and Security)*|System|Advanced
System Settings|Environment Variables and select Path and
click Edit
* Windows 8/10 only
• Mac
– use terminal program
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15. Creating a local repo
• git init
– creates a local repository in current folder by
creating a hidden .git subfolder
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16. Lifecycle of Files
• git status
– displays the status of your project’s files
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17. Basic commands
• Add files to staging area
– git add
• Commit files to local repo
– git commit –m “message”
• Unstage changes
– git reset
• Check status of project files
– git status
TIP: You can create rules
which automatically ignore
certain types of files (e.g.,
DLLs, .sln, .proj) by git by
using a .gitignore file. The
ignored files will not be
tracked/added/committed
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18. Commit Versions
• Display log of commits
– git log
each commit is listed with its SHA-1 checksum which you can use to refer
to the commit using other commands
• Display log of commits with list of changes
– git log -p
• Revert to prior commit & discard history since
– git reset --hard commit
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19. Differences
• Diff between unstaged (but tracked) changes
and staged changes
– git diff
• Diff between staged and last commit
– git diff --staged
• Diff between two different commits
– git diff commit1 commit2
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20. Working with a remote repo
• git clone url folder
– makes a copy of a remote git repository from url
into the local folder
– also names the remote “origin” and sets it as
default remote
• git remote add name url
– Creates link between current repo and named
remote repo
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21. Git Hosting Services
• GitHub
– free for public, open source repos
– $ for private repos
• Bitbucket
– free for up to 5-person team private repos
• VS Online
– free for up to 5-person team private repos
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22. Exchanging changes with remote
• git pull
– downloads remote changes and merges them into
your repo
• git push
– uploads local committed changes to remote
– git push –u origin master
• pushes content to origin remote from master branch
and remembers your remote and branch settings
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23. Litwin Git for the Unitiated 23

24. Litwin Git for the Unitiated 24

25. Using git from VSCode

26. Code and git (1 of 3)
• VS Code can…
– create a local repo
– add files to staging area
– commit files
– pull/push to remote
– show diffs
– view git command history
• VS Code cannot…
– clone a repo
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27. Code and git (2 of 3)
total # of
changes
Change icons
A – added
M – modified
D – deleted
U – untracked
Commit with
message
refresh
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28. Code and git (3 of 3)
context sensitive actions when
rolling over file name
click on file name to see diff
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29. Using git from Visual Studio

30. Using git from Visual Studio 2015
• Git also works with Visual Studio 2015 (and
2013)
• Unlike VS Code, Visual Studio can clone
• One big oddity about Visual Studio and git
– There is no staging of changes
– You commit directly (equivalent to git commit -a)
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31. Working with git from Visual Studio 2015
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32. Branching and merging

33. Branching
• every git repo starts with master branch
• git branch newBranch
– creates branch named newBranch
• git checkout newBranch
– switches to branch newBranch
– changes files in working directory to new branch
• git checkout –b newestBranch
– create & switch to newestBranch branch in 1 step
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34. Merging
• Two steps
1. git checkout branchToMergeTo
2. git merge branchToMergeFrom
Any merge conflicts will need to be resolved and the resulting changes
committed
• Deleting a branch
– git branch –d branchToDelete
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35. More on branches
• git branch
– no arguments; lists all branches
• git branch --merged
– lists all branches you have merged with
• git branch --no-merged
– lists all branches you have not merged with
• git diff branch1 branch2
– shows differences between two branches
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36. Branches & remotes
• gets a little more complicated
– git fetch remote
• download all history from remote but don’t integrate
– git pull remote branch
• download & merge remote commits into local branch
– git push remote branch
• send branch commits to remote branch
Homework: Read chapter 3 (Git Branching) of
https://git-scm.com/book/en/v2 for more on branching
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37. Stashing
• git stash
– temporarily stashes away all tracked changes so you
can switch to another branch
• git stash apply
– reapplies most recently stashed changes
• git stash drop
– deletes most recently stash
• git stash pop
– reapplies most recently stashed changes and deletes
the stash
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38. Wrap Up

39. Wrap Up
• git is a distributed source control repository that
has a lot of power & a groundswell of developer
community support
• You can use git from
– command line
– VS Code
– Visual Studio
– other git GUI tools
• I’ve only scratched the surface of git
– See next slide for resources where you can learn more
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40. Resources
• Download git
– http://git-scm.com
• Various resources
– https://git-scm.com/documentation
• Free book -- Pro Git
– https://git-scm.com/book/en/v2
• Interactive tutorial
– https://try.github.io/
• Cheat sheets
– http://www.git-tower.com/blog/git-cheat-sheet/
– http://ndpsoftware.com/git-cheatsheet.html
– https://training.github.com/kit/downloads/github-git-cheat-sheet.pdf
• Git GUI tools (useful for visualizing branches)
– Source Tree: https://www.sourcetreeapp.com/
– GitHub Desktop: https://desktop.github.com/
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41. Slides can be found here…
• http://tinyurl.com/litwin-sea-web
Litwin Git for the Unitiated 41
Thank you!