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