index.Rpres

<meta property="og:title" content="Learn the Basics of Git">
<meta property="og:type" content="website">
<meta property="og:url" content="https://norfolkdatasci.github.io/learning-git">
<meta property="og:image" content="https://raw.githubusercontent.com/NorfolkDataSci/learning-git/master/img/learn-git.png">

<div class="logo">
  <a href="http://www.meetup.com/NorfolkDataSci/" target="_blank">
  <img src="./img/norfolk-data-sci-logo.png" style="width:200px;" alt="logo">
  </a>
</div>

<div class="copyright">
Norfolk Data Science: <a href="http://www.meetup.com/NorfolkDataSci/" target="_blank">http://www.meetup.com/NorfolkDataSci/</a>
</div>

Learning Git
========================================
author: Josiah Baker & Steve Mortimer
date: November 1, 2016
css: presentation-css.css

```{r setup, include=FALSE}
  library(knitr)
  knitr::opts_chunk$set(echo=TRUE, eval=TRUE)
```

Installing git
====================================================
title: false

<h3>
  Installing <span style="font-family: monospace">git</span>
</h3>
<ul style="padding-bottom:20px;padding-top:40px;">
  <li>
    Instructions for installing on all platforms (Linux, Mac, Windows) are available here:<br> 
    <a target="_blank", href="https://git-scm.com/book/en/v2/Getting-Started-Installing-Git">
      https://git-scm.com/book/en/v2/Getting-Started-Installing-Git
    </a>
  </li>
  <li>You can verify that your installation worked by checking the version of Git from the command line.
  <ul style="padding-left:40px;">
    <li>Mac Users: Open up your terminal</li>
    <li>Windows Users: Open up Git Bash</li>
    <li>Run the following command:</li>
  </ul>
  </li>
</ul>

```
git --version
```

Generating Your SSH Key
====================================================
title: false

<h3>
  Generating Your SSH Key
</h3>
<ul style="padding-bottom:20px;padding-top:40px;">
  <li>
    Check for existing keys<br>
    <div style="font-size:60% !important;" class="code-div">
      ls -al ~/.ssh
    </div>
  </li>
  <li>
    If you don't have keys, then generate a key<br>
    <div style="font-size:60% !important;" class="code-div">
      ssh-keygen -t rsa -b 4096 -C "YourEmail@mail.com"
    </div>
  </li>
  <li>
    Start the key agent<br>
    <div style="font-size:60% !important;" class="code-div">
      eval "$(ssh-agent -s)"
    </div>
  </li>
  <li>
    Add the key to the agent<br>
    <div style="font-size:60% !important;" class="code-div">
      ssh-add ~/.ssh/id_rsa
    </div>
  </li>
</ul>

<div class="footer">
  <a target="_blank" href="https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/">
    https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/
  </a>
</div>

Copy Public Half of SSH Key to GitHub
====================================================
title: false

<h3>
  Copy Public Half of SSH Key to GitHub
</h3>

<div class="wrapper">
  <ul>
    <li>
      Log into GitHub -> Settings -> SSH and GPG keys
    </li>
    <li>Copy the key to clipboard and Paste 
    <ul style="padding-left:40px;">
      <li>Mac Users<br>
        <div class="code-div">
          pbcopy < ~/.ssh/id_rsa.pub
        </div>
      </li>
      <li>Windows Users<br>
        <div class="code-div">
          cat ~/.ssh/id_rsa.pub > /dev/clipboard
        </div>
      </li>
    </ul>
    </li>
  </ul>
  <img height="40%" src="./img/pasting-ssh-key.png">
</div>

<div class="footer">
  <a target="_blank" href="https://help.github.com/articles/adding-a-new-ssh-key-to-your-github-account/">
    https://help.github.com/articles/adding-a-new-ssh-key-to-your-github-account/
  </a>
</div>

Create your own repo on Github
====================================================
title: none

<h3>
  Create your own repo on Github
</h3>

<ul>
  <li>
    <div>
      <span style="">Click on button to create new repository</span>&nbsp;&nbsp;
      <img style="vertical-align:middle" src="./img/new-repo-button.png">
    </div>
  </li>
  <li>
    Repositories are a folder<br>
    Create a folder with same name as new repo
    <div class="code-div">
      mkdir ~/members<br>
      cd members
    </div>
  </li>
  <li>
    Copy/Paste the GitHub commands
    <div style="font-size:50% !important;" class="code-div">
      echo "# test" >> README.md<br>
      git init<br>
      git add README.md<br>
      git commit -m "first commit"<br>
      git remote add origin git@github.com:{UserName}/members.git<br>
      git push -u origin master<br>
    </div>
  </li>
</ul>


Create your own repo on Github (cont.)
====================================================
title: none

<h3>
  Create your own repo on Github (cont.)
</h3>

<ul>
  <li>
      The first command initializes the repository<br>
      <div class="code-div">
        git init
    </div>
  </li>
  <li>
    The second command tells git to track an <i>individual</i> file<br>
    <div class="code-div">
      git add README.md
    </div>
  </li>
  <li>
    This commits changes on a tracked file<br>
    <div class="code-div">
      git commit -m "first commit"
    </div>
  </li>
  <li>
    Now we tell git where our remote repository is<br>
    <div class="code-div">
      git remote add {name} git@github.com:{UserName}/members.git
    </div>
  </li>
  <li>
    Save your local commited changes to the remote repository<br>
    <div class="code-div">
      git push -u {name} {branch name}
    </div>
  </li>
</ul>


Making a Commit (Adding to README)
====================================================
title: none

<h3>
  Making a Commit (Adding to README)
</h3>

<ul class="extra-li-top-pad" style="padding-bottom:40px;padding-top:40px;">
  <li>
    Add your Name to the README file as a bullet
  </li>
  <img src="./img/making-a-commit.png">
  <li>
    Save your changes
  </li>
  <li>
    "Stage" all files, commit, then push to GitHub
    <div style="font-size:70%;" class="code-div">
      git add .<br>
      git commit -m "Update README" -m "Add Change"<br>
      git push origin master<br>
    </div>
  </li>
</ul>

<div class="footer">
  Guidelines on how to make good commit messages:&nbsp;&nbsp;
  <a target="_blank" href="http://chris.beams.io/posts/git-commit/">
    http://chris.beams.io/posts/git-commit/
  </a>
</div>

Clone a Repo
====================================================
title: none

<h3>
  Clone a Repo
</h3>

<ul class="extra-li-top-pad" style="padding-bottom:20px;padding-top:40px;">
  <li>
    Navigate to where you want repo to be<br>
    <div class="code-div">
      mkdir ~/my-repos<br>
      cd ~/my-repos
    </div>
  </li>
  <li>
    Copy/Paste the GitHub commands
    <div class="code-div">
      git clone git@github.com:NorfolkDataSci/members.git<br>
    </div>
  </li>
  <li>
    Check that a folder with same name as the repo was 
    created in the current working directory
  </li>
</ul>


Fixing a Merge Conflict
====================================================
title: none

<h3>
  Fixing a Merge Conflict
</h3>

<ul class="extra-li-top-pad" style="padding-bottom:20px;padding-top:40px;">
  <li>
    When 2 people change the same lines of code it creates a "merge conflict" 
  </li>
  <li>
    Merge conflicts need to be "resolved", meaning reconcile the differences between commits
  </li>
  <li>
    The first sign is not being able to push your recent commits
  </li>
  <img src="./img/cannot-push.png">
</ul>

Fixing a Merge Conflict (cont.)
====================================================
title: none

<h3>
  Fixing a Merge Conflict (cont.)
</h3>

<ul class="extra-li-top-pad" style="padding-bottom:20px;padding-top:40px;">
  <li>
    So you follow the hint and pull
    <div class="code-div">
      git pull
    </div>
  </li>
  <li>
    Then you receive a message about a "CONFLICT"<br>(fix conflicts, then commit)
  </li>
  <img src="./img/after-pulling.png">
</ul>

Fixing a Merge Conflict (cont.)
====================================================
title: none

<h3>
  Fixing a Merge Conflict (cont.)
</h3>

<ul style="padding-bottom:10px;padding-top:10px">
  <li>
    Open up the conflicted file (in this case README.md)
  </li>
  <img height="150px !important;" src="./img/seeing-the-diff.png">
  <li>You will notice weird markings
  <ul style="padding-left:40px;">
    <li>The marker showing the start of the conflict
      <div class="code-div">
        "<<<<<<< HEAD"
      </div>
    </li>
    <li>The marker showing the end of your change (HEAD)
      <div class="code-div">
        "======="
      </div>
    </li>
    <li>The marker showing the end of the server's version
      <div class="code-div">
        ">>>>>>> 7bd926b......"
      </div>
    </li>
  </ul>
  </li>
</ul>

Fixing a Merge Conflict (cont.)
====================================================
title: none

<h3>
  Fixing a Merge Conflict (cont.)
</h3>

<ul class="extra-li-top-pad" style="padding-bottom:10px;padding-top:10px">
  <li>
    Open up the conflicted file (in this case README.md)
  </li>
  <li>
    Edit file to how you want it. Make sure to remove weird markings
  </li>
  <img src="./img/fixed-conflict.png">
  <li>Commit like any other change and you're done (Resolved!)
    <div class="code-div">
      git add .<br>
      git commit -m "Fix merge conflict"<br>
      git push<br>
    </div>
  </li>
</ul>

Fixing or Resetting Work
====================================================
title: none

<h3>
  Fixing or Resetting Work
</h3>

<ul style="padding-bottom:20px;padding-top:40px;">
  <li>
    It's possible to erase commits back to a certain point
  </li>
  <ul style="padding-left:40px;padding-top:10px;">
    <li>
      <div>
        <span style="">Click on the commits button to view</span>&nbsp;&nbsp;
        <img style="vertical-align:middle" src="./img/commits-button.png">
      </div>
    </li>
    <li>Click copy button to get commit hash on clipboard</li>
  </ul>
  <img src="./img/commit-hash.png">
  <li>
    Run the following command to reset your local commit history
    <div class="code-div">
      git reset &ndash;&ndash;hard 2feeb51899f80a2ddea5b353260841350285406f
    </div>
  </li>
  <li>
    Commit like any other change, but add "-f" on your <span style="font-family: monospace">git push</span>
    <div class="code-div">
      git push -f
    </div>
  </li>
</ul>

Working on a Branch
====================================================
title: none

<h3>
  Working on Branches + a Pull Request
</h3>

<ul style="padding-bottom:20px;padding-top:40px;">
  <li>
    Start work on a "branch". It's a copy of your current state
    <div class="code-div">
      git checkout -b my_branch
    </div>
  </li>
  <li>
    This branch is only local, so push it to GitHub
    <div class="code-div">
      git push -u origin my_branch
    </div>
  </li>
  <li>
    Make a change to the README.md file, commit, & push
  </li>
  <li>
    Next switch back to master branch and look at README.md
  </li>
    <div class="code-div">
      git checkout master
    </div>
  </li>
  <li>
    Your change is gone! It only exists on "my_branch". Switch back now
  </li>
    <div class="code-div">
      git checkout my_branch
    </div>
</ul>


Branching + Pull Request
====================================================
title: none

<h3>
  Branching + Pull Request
</h3>

<ul style="padding-bottom:20px;padding-top:40px;">
  <li>
    Branches isolate code until ready to be "merged"<br>
    Create a pull request when you are ready to merge
  <ul style="padding-left:40px;padding-top:10px;">
    <li>Look in GitHub for "my_branch"</li>
    <li>Click the button that says "Compare & pull request"</li>
  </ul>
  <img src="./img/create-pull-request.png">
  <li>
    Pick a "target" branch (where you want new code to be applied) 
  </li>
  <li>
    Review that your changes make sense
  </li>
  <li>
    Add a message outlining why this pull request is needed and
    how it essentially solves the problem of why it was needed
  </li>
</ul>


Items Still Not Covered
====================================================

* Stashing work with <span style="font-family: monospace;  font-size: 85%;">git stash</span> and 
<span style="font-family: monospace;  font-size: 85%;">git stash pop</span>
* More advanced branching with <span style="font-family: monospace;  font-size: 85%;">git checkout</span> 
* Forking and staying current with <span style="font-family: monospace;  font-size: 85%;">git rebase</span> 
* Closing issues via commit messages (more info <a target="_blank" href="https://help.github.com/articles/closing-issues-via-commit-messages/">here</a>)
* Other ways to fix or undo your git history (more info <a target="_blank" href="https://github.com/blog/2019-how-to-undo-almost-anything-with-git">here</a>)
* Git LFS (Large File Store) for versioning large data files