Git and github introduction

1. Git and github introduction
Qiang Zhang
May 27,2014

2. ABOUT GIT

3. what is git?
• git is CVS tool.
• The major difference between git and other CVS:
if files have not changed, Git doesn’t store the
file again—just a link to the previous identical
file

4. Features
• Nearly Every Operation Is Local
• Git has three main states that your files can
reside in: committed, modified, and staged.
• Folk and pull model

5. An “hello world” example of git
• Install and intialize an empty git repo
>> sudo apt-get install -y git-core
>> mkdir myrepo
>> cd myrepo
>> git config --global user.name "John Smith"
>> git config --global user.email
"example@stanford.edu"
>> git init # Initialized empty Git repository in
/home/ubuntu/myrepo/.git/
>> git status

6. Edit file and add it into git
>> git add file.txt
>> git status
>> git commit -m "Added first file"
>> git log

7. Main states of git
• Git has three main states that your files can
reside in:
– modified
– staged
– committed

8. state: modified
• Modified means that you have changed the file
but have not committed it to your database yet
• For example: you use vim open file.txt and add
“hello, world” string. So file.txt is in modified
state.
• related commands: git checkout -- <filename>
(undo the modification)

9. state: staged
• Staged means mark a modified file which will go
into your next commit.
– If it’s modified and added to the staging area(git add
file.txt), it is staged.
– Otherwise, it is modified.
• Related commands: git add, git diff --staged, git
reset, git rm

10. state committed
• Committed means that the data is safely stored
in your local database.
• So git can trace all those changes.
• For example
>> git commit -m "Added first file“
Related commands:

11. Whole flow: Edit another file
and add to git
Edit your file locally
git status
git diff file.txt
git add file.txt
git commit -m "Added a new line to the file."
Command help output the committed logs
git log
git log -p
git log -p --color

12. CONTRIBUTE TO A PROJECT WITH
GITHUB

13. What is push ?
• When you have your project at a point that you
want to share, you have to push it upstream.
• Command: git push [remote-name] [branch-
name]
• For example: git push -u origin master
push local change to origin repo. The -u tells Git to
remember the parameters, so that next time we
can simply run git push

14. What is pull ?
• git-pull - Fetch from and integrate with another
repository or a local branch
• In its default mode: git pull = git fetch + git merge
FETCH_HEAD
For example
• git pull origin master
Fetch the specified remote’s copy of the current
branch and immediately merge it into the local copy.

15. Create repo in github
• create repo in github website and push your
commit
– git remote add origin https://github.com/username/Hello-
World.git
# Creates a remote named "origin" pointing at your
GitHub repository
– git push origin master
# Sends your commits in the "master" branch to
GitHub origin

16. Build the environment
1. Folk the repository on github website
2. Clone your folk:
git clone https://github.com/username/Spoon-
Knife.git
3. Configure the remote:
cd Spoon-Knife
git remote add upstream <original repository>
git fetch upstream
git merge upstream/master

17. first successful bugfix and
merge
1. Create the branch and switch to this branch
git branch Issue2020
git checkout Issue2020
2. Make change at your branch:
git status
git add <file name>
git commit -m “comments”
3. Switch to master repo and merge code
1. git checkout master
2. git merge Issue2020
3. git branch -d Issue2020 #delete Issue 2020 repo
4. Push your change back to github:
git push origin master

18. Web resource
• https://try.github.io
step by step guide
• https://www.atlassian.com/git/
Very good tutorial and workflow of git
• Git cheatsheet