Git 4 graioners

... Git just want to have fun and you should too

by Marcia Paez Aballay, Ramiro Berruezo & Santiago Rojo

Agenda

• VCS
• Why Git?
• What's inside?
• What's a branch?
• Git commands
• Undoing stuffs
• Branches
• Branching model
• Remotes
• Merge
• Rebase
• Differences
• Configurations
• Applications and tools

What is a VCS?

“Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later.”

But really, is something more like...

What kind of VCS exists?

Centralized vs. Decentralized vs. Distributed

Why Git?

• Fully distributed
• Almost everything is local
• Works without network
• Every workstation is a backup
• Only adds data
• Branches

Git off-line

• Faster
• Diff between everything
• See the full log
• Commit changes
• Merge/Rebase branches
• Get a previous version of a file
• Switch branches
• and more

What's inside?

Where is my code?

Workflow

What's a branch?

... are just pointers

... but HEAD is an important one.

Git commands

git help is your BFF :3

Initialize a repository

$ git init
Initialized empty Git repository in /home/tiagox/KeepGITSimple/.git/

Using an existing repository

$ git clone http://dev.graion.com/git/keepgitsimple
Cloning into 'keepgitsimple'...
...
Checking connectivity... done

Status

$ git status

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#       modified:   index.html
#
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#       modified:   index.html
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       README.md

Adding files and changes

all

$ git add .

files

$ git add README.md

patterns

$ git add src/*.java

interactive (+1)

$ git add -p

Removing files and changes

files

$ git rm README.md

patterns

$ git rm src/*.java

clean untracked

$ git clean -f

Commiting changes

$ git commit

$ git commit -m "Commit message."

add + commit

$ git commit -am "Commit message."

Cherry picking

$ git cherry-pick 5123dad9ce82d6a91b2d027015bfe9d907dcda7b

(╯°□°)╯︵ ┻━┻

DEMO TIME!

Get other's commits

$ git fetch origin
$ git merge origin/this_branch

$ git fetch origin
$ git rebase origin/this_branch

... or just

$ git pull origin

$ git pull origin --rebase

conflicts?

Caused by git pull/merge

$ git pull origin

CONFLICT!

$ git mergetool
# resolve
$ git commit

Caused by git pull/rebase

$ git pull origin --rebase

CONFLICT!

$ git mergetool
# resolve
$ git rebase --continue

if you just don't want any trouble

$ git rebase --abort

solved!

Share your commits

$ git push origin local_branch:remote_branch --set-upstream

don't be proud of use

$ git push origin local_branch:remote_branch --force

Undoing stuffs

git checkout

discarting changes

$ git checkout -- some_file

DISCLAIMER!

git reset

removing from stage

$ git reset HEAD some_file

undo last commit keeping changes

$ git reset HEAD~1

undo last commit discarting changes

$ git reset HEAD~1 --hard

... or you can space/time travel through your commits

$ git reset HEAD~4^3^^^2^1

$ git reset other_branch

$ git reset origin/this_branch

Branches

... again

Create branches

$ git branch playground

$ git checkout -b development
Switched to a new branch 'development'

Delete branches

$ git branch -d playground

$ git branch -D playground

List branches

$ git branch
* development
  master
  playground

Switch branches

to another branch

$ git checkout playground
Switched to branch 'playground'

... or go anywhere

$ git checkout 5123dad9ce82d6a91b2d027015bfe9d907dcda7b

Note: checking out '5123dad9ce82d6a91b2d027015bfe9d907dcda7b'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b new_branch_name

HEAD is now at 5123dad... Add index file.

Stashing

$ git stash

$ git stash save "Comments"

$ git stash list

$ git stash apply

$ git stash drop

apply + drop

$ git stash pop

Branching model

Use case

Remotes

Merge

$ git checkout master
Switched to a new branch 'master'
$ git merge feature

$ git merge feature
Updating 306eb60..56a2247
Fast-forward
 index.html | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

$ git checkout master
Switched to a new branch 'master'
$ git merge feature

$ git merge feature
Auto-merging index.html
Merge made by the 'recursive' strategy.
 index.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Fast-forward

Recursive strategy

Rebase

$ git checkout master
Switched to a new branch 'master'
$ git rebase feature

$ git rebase feature
First, rewinding head to replay your work on top of it...
Fast-forwarded master to feature.

$ git checkout master
Switched to branch 'master'
$ git rebase feature

$ git rebase feature
First, rewinding head to replay your work on top of it...
Applying: c3

DON'T

let's try again

$ git checkout feature
Switched to branch 'feature'
$ git rebase master

$ git rebase master
First, rewinding head to replay your work on top of it...
Applying: c4
Applying: c5
Applying: c6

$ git checkout master
Switched to branch 'master'
$ git merge feature
Updating 306eb60..56a2247
Fast-forward
 index.html | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Wrong rebase

Rebase-Merge

Differences

Local changes

$ git diff

$ git diff --staged

Between branches

$ git diff this_branch other_branch

$ git diff this_branch other_branch -- some_file

$ git diff this_branch:some_file other_branch:some_file

... order matters

Whose fault is it?

$ git blame main.c

f10525b3 (Ramiro Berruezo 2013-01-19 12:24:25 -0300 1) #include <stdio.h>
f10525b3 (Ramiro Berruezo 2013-01-19 12:24:25 -0300 2)
80c5d84a (Marcia Paez     2013-01-18 14:16:03 -0300 3) int main (void) {
b63aa62d (Santiago Rojo   2013-01-18 12:20:12 -0300 4)
f10525b3 (Ramiro Berruezo 2013-01-19 12:24:25 -0300 5)    printf("Hello world!");
b63aa62d (Santiago Rojo   2013-01-18 12:20:12 -0300 6)    return 0;
b63aa62d (Santiago Rojo   2013-01-18 12:20:12 -0300 7)
b63aa62d (Santiago Rojo   2013-01-18 12:20:12 -0300 8) }
b63aa62d (Santiago Rojo   2013-01-18 12:20:12 -0300 9)

Configurations

One time configurations

$ git config --global user.name "Santiago Rojo"

$ git config --global user.email santiago.rojo@graion.com

$ git config --global color.ui true

$ git config --global merge.tool meld

$ git config credential.helper store

$ git config --global --list

Alias

$ git config --global alias.lol "log --oneline --graph"

$ git lol
*   9d36fd6 Merge branch 'helloworld'
|\
| * 28ebd5c Add hello world message.
* | 3a76a29 Added .gitignore.
|/
* 1e2dde5 First commit.

... or even more cool.

$ git config --global alias.gol "log --graph --pretty=format:'%Cred%h%Creset - %C(blue)%an%Creset
%C(yellow)%d%Creset %s %Cgreen(%cr)%Creset' --abbrev-commit --date=relative"

$ git gol
*   9d36fd6 - Santiago Rojo  (HEAD, master, helloworld) Merge branch 'helloworld' (11 months ago)
|\
| * 28ebd5c - Santiago Rojo  (tag: just-branched) Add hello world message. (11 months ago)
* | 3a76a29 - Santiago Rojo  Added .gitignore. (11 months ago)
|/
* 1e2dde5 - Santiago Rojo  First commit. (11 months ago)

Ignoring things

• .gitignore
• .git/info/exclude

.netbeans
.DS_Store
*.o
*.dll
!main.dll
*.class

Applications and tools

Linux

$ sudo apt-add-repository ppa:pdoes/ppa
$ sudo apt-get update
$ sudo apt-get install git gitk

Windows

1. http://git-scm.com/download/win
2. Next, next, next...

gitk

SmartGit

Links

• Git official site (http://git-scm.com)
• Try Git (http://try.github.io/)
• LearnGitBranching (http://pcottle.github.io/learnGitBranching/)
• Interactive cheatsheet (http://ndpsoftware.com/git-cheatsheet.html)
• Git ready (http://gitready.com/)

Thank you