Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.
Git tracks changes.
now git.com connected

git commands:

git add readme.txt
git commit -m "xxxxx "

git status
git log
git log --pretty=oneline

git diff HEAD -- readme.txt 

设置远程地址输入以下两个命令行：
$ git remote set-url origin https:xxxxx.git
$ git push -u origin master


git remote add origin0 https://github.com/aaron-lui/learngit.git

git remote -v

git push -u origin0 master