Install

sudo apt-get update 
sudo apt-get install git

git config --global user.name "your_ame"  
git config --global user.email "youremail@domain.com"

ssh-keygen -C `youremail@domain.com` -t rsa

Continuous press enter and no password set

cd  ~/.ssh/
more id_rsa.pub

paste it on Settings-ssh and GPG keys-new SSH key-ok

vi ~/.gitconfig

after added the following contents , the next time you enter your username and password ,

git can remember that and you won`t have to enter later

[credential]
    helper = store

Change password

cd ~/.ssh/
ssh-keygen -f id_rsa -p
cd ~/Document/dockerfiles

Start a repository

git init
touch Readme
git add Readme
git commit -m `add readme file`
connect local repository with github repository：
git remote add origin https://github.com/your_github_name/your_github_repository_name.git
git push origin master

Clone a repository

git clone https://github.com/your_github_name/your_github_repository_name.git
git add Readme_new
git commit -m `add new readme file`
git commit -a
git push origin master

After made change at master branch

git pull origin master

While mkdir

remember that the new dir should`not be emply to add to git

mkdir linux
cd linux
touch readme
cd ..
git add linux
git commit -m `add linux`
git push origin master

While delete

rm *.xml
git rm *.xml
git commit -m "delete *.xml"
git push origin master