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Git started
Introduction to
distributed
version control
with Git
Yannick Baron
@yannick_baron
[email protected]
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“Git is easy”
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Clone the repository
“Git is easy”
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Clone the repository
Make changes
“Git is easy”
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Clone the repository
Make changes
Mess things up
“Git is easy”
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Clone the repository
Make changes
Mess things up
Look at StackOverflow
“Git is easy”
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Clone the repository
Make changes
Mess things up
Look at StackOverflow
Mess things up even more
“Git is easy”
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Clone the repository
Make changes
Mess things up
Look at StackOverflow
Mess things up even more
Delete folder
“Git is easy”
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Clone the repository
Make changes
Mess things up
Look at StackOverflow
Mess things up even more
Delete folder
Clone the repository
“Git is easy”
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Clone the repository
Make changes
Mess things up
Look at StackOverflow
Mess things up even more
Delete folder
Clone the repository
…
“Git is easy”
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https://stackoverflow.com/questions?tab=Votes
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https://stackoverflow.com/questions?tab=Votes
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Using git for 12 years now
Noticed very different levels of
experience
Concepts often misunderstood
despite daily use
I <3 git
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Time travel: Go back in time
History of how project evolved
Compare versions to find errors
Build releases on versions
Work on the same files in parallel
Why version control?
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Time travel: Go back in time
History of how project evolved
Compare versions to find errors
Build releases on versions
Work on the same files in parallel
Why version control?
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Save our butts
Make us feel safe when confidently
editing code
Why version control for real?
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Comfortable with Git?
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Comfortable with Git?
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Changes are kept track of locally
Most operations performed locally
Server mostly for storage only
Control of when to communicate
with a remote machine
= fast + independent of connection
Distributed?
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Story: Writing a “book” with git
Live Demo
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Intro + chapter files
Script to bundle them to a book
Demo Project
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git init
initializes a git repository
git status
information about the current state
git add
adds current version of a file
git commit –m “”
saves added files to the history
Gitting started is easy
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The git history is a graph, a tree to
be precise
A node in that tree is the state of
our files at a point in time
Most operations deal with how to
navigate and manipulate that tree
The git history
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A hierachical graph data structure
Consists of nodes and edges
Various ways of implementation
fixed number of child nodes
list of child nodes
reference to parent node
…
Quick Interlude: Trees
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Reference to parent node
Node {
parent?: Node;
data: any;
}
const A = new Node();
Quick Interlude: Trees
A
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Reference to parent node
Node {
parent?: Node;
data: any;
}
const t = new Node();
t.parent = A;
A = t;
Quick Interlude: Trees
A
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Reference to parent node
Node {
parent?: Node;
data: any;
}
const B = A;
Quick Interlude: Trees
A B
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Reference to parent node
Node {
parent?: Node;
data: any;
}
const t = new Node();
t.parent = B;
B = t;
Quick Interlude: Trees
B
A
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Reference to parent node
Node {
parent?: Node;
data: any;
}
Quick Interlude: Trees
B
A
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Reference to parent node
Node {
parent?: Node;
data: any;
}
B = undefined;
Quick Interlude: Trees
A
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The git history is a graph, a tree to
be precise
A node in that tree is the state of
our files at a point in time
Most operations deal with how to
navigate and manipulate that tree
The git history
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git add --all
adds all untracked files at once
git status
information about the current state
git commit –m “”
saves added files to the history
Growing the tree
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git branch
creates a new branch at HEAD
git checkout
moves HEAD to branch
git commit –am “”
-a add all tracked files & commits
Adding a branch
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git checkout
moves HEAD to branch
git diff
show the diff of current changes
--word-diff do a word diff
git commit –am “”
-a add all tracked files & commits
Switching branches
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git diff
diff between HEAD and given branch
git checkout
moves HEAD to branch
git merge –m “”
merges branch into current branch
git branch –d
deletes given branch
Reintegrating a branch
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git init
git status
git add
git commit
git branch
git checkout
git diff
git merge
Recap #1
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git log
shows full detail log of all commits
git log --oneline
shows list of commit messages
git log --graph --oneline
shows graph of commit messages
The Log and Hashes
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https://stackoverflow.com/questions/1057564/pretty-git-branch-graphs/35075021#35075021
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git checkout --
checks out file in given version
git diff --staged
shows a diff of the staged files
git reset --hard
move current branch back to SHA
--hard discard all changes
--soft keep changes
We have to go back!
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git remote add
adds a remote repository
git push -u
push branch and setup tracking
Going online for the first time
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Starting from existing Repo
git clone []
makes working copy of repo at url
git log --graph --oneline
shows graph of commit messages
Multiplayer
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git checkout –b
-b create and switch to branch
git commit –am “”
-a add all tracked files & commits
git push
push changes of current branch
Player 2 has entered the game
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git fetch
download changes from the remote
git checkout
moves HEAD to branch
git pull
fetches and merges tracked branch
into current branch
git rebase
replay branch’s commits on top of
base
Receiving changes
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git merge –m “”
merges branch into current branch
git commit –am “”
-a add all tracked files & commits
git push :
deletes branch on remote
git branch –d
deletes given branch
Dealing with conflicts
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git log
git reset
git clone
git remote
git push
git fetch
git pull
git rebase
Recap #2
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We have seen 16 basic commands
That’s all you need to git started
Just the tip of the iceberg
Git is a skill, a tool in your tool belt
Expertise makes your life easier
Low cost, high reward
Try it!
Git going!
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and their features
GitHub https://github.com
BitBucket https://bitbucket.org
GitLab https://gitlab.com
Create online repositories
Fork Repositories
Pull Requests
Tools for Code Reviews
Continuous Integration
Build Pipelines
Web platforms
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GitHub interactive Introduction
https://try.github.io/
Think like a git
http://think-like-a-git.net/
Watch this talk again
https://youtu.be/S_OkNMHinlg
GitHub Git Cheatsheet
https://services.github.com/on-
demand/downloads/github-git-
cheat-sheet.pdf
Resources
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git reset # to unstage
git commit --amend
git pull --rebase
(demo) conflict when rebasing
git revert
git add -p
git rebase –i
git stash
git bisect
uncommit
Bonus Round