title : Basic Git Commands

* Once you have a repository, you'll probably make changes over time

* Often, you'll want to share these changes with others (users, followers, collaborators, etc.)

* __Git__ allows you to track your changes locally (on your computer)

* __GitHub__ allows you to share your changes with the world (or just a few people, depending on whether your repo is public or private)

* But how to communicate between Git and GitHub?

* First we'll review some basic commands, then we'll look at a typical workflow

<img class=center src=../../assets/img/01_DataScientistToolbox/gghuboverview.png height='500'/>

* Suppose you add some new files or make changes to a local repository (on your computer)

* You need to let Git know that you want it to pay attention to these files (i.e. "track" these files)

* From the directory where the repo is located on your computer (in Git Bash or Terminal, depending on whether you're on Windows or Mac, respectively):

* `git add .` adds all new files (note the period after `add`, which represents "all files")

* `git add -u` updates tracking for files that changed names or were deleted

* `git add -A` or `git add --all` does both of the previous

* You want to organize and save "snapshots" of the files you've staged for commit

* You type the command

* `git commit -m "your message goes here"`, substituting a useful description (between the double quotes) of what changes you made since the last committed changes

* This only updates your local repo, not the remote repo on GitHub

* To see a log of the commits you've made locally, type `git log`

* Spacebar advances page by page

* Return advances line by line

* Typing the letter "Q" exits the log

* Once you are pleased with your local commits, you would like to update the remote repo (on GitHub)

* The command `git push` sends your most recent commits to GitHub, updating your remote repository for the world to see

* If you fork someone else's repo and make some changes or additions, you may want the original author to merge your changes into their code

* To do so you need to issue a pull request via GitHub

* Don't need anyone's permission to fork and make changes, but the original author is not obligated to accept your changes

* Pull requests offer a powerful means of contributing to open source software

<img class=center src=../../assets/img/01_DataScientistToolbox/pull_request1.png height='150'/>

* Git documentation [http://git-scm.com/doc](http://git-scm.com/doc)

* Github help [https://help.github.com/](https://help.github.com/)

* Google/Stack Overflow are great for Github