Getting started with github, git and R-studio.

This is a basic tutorial on how to configure, set up, and link github with RStudio. The end goal of this tutorial is to have you establish a Github account, install Git, and learn how to get Git working smoothly in the shell (i.e., terminal, cmd line, etc.) and in the RStudio IDE (Integrated Development Environment). Whether you decide to use Github for version control for your projects in RStudio or something else, this tutorial should help you with integrating Git and Github into your daily work with R, RMarkdown, and Quarto. This tutorial draws from the more comprehensive Happy Git and Github for the UseR by Jennifer Bryan.

This tutorial uses R and RStudio. If you don’t already have those installed, you will need to install them to your local computer. Follow the link to Download R and RStudio Desktop.

Creating a github account

You will need to create a Github account. Let’s do that first.

Go to the github website and signup with your email and password.

Once you have a github site, in the upper left hand corner on your github site create a repository (‘repo’ for short) for where you want files from your pending project to go. Name the repository whatever you will be calling your project. Select to have a README file where you can post notes about the project. (once you have established a working connection between a Github repo and an RStudio project, you’ll learn how to make a README.Rmd file that will automatically sync with the README.md file of your project). Select to make your repository private while you are working on it (this can be changed later).

Once you hit create you new repository should look something like this:

Getting started with git on your computer

You will need to have a Git client installed on your local computer (Follow this link for more detailed instructions link).

There are many options to choose from. If you are using Windows, an easy choice is to install Git for Windows.

If you are using a macOS, you have at least three options;

• Option 1: Install the Xcode command line tools (not all of Xcode), which includes Git.

Go to the shell/terminal in RStudio and enter this command to elicit an offer to install developer command line tools:

xcode-select --install

• Option 2: Install Git from here: website

• Option 3: Install Homebrew and then run the following in the shell/terminal

brew install git

Check if you have git installed on your computer. For this you have to use terminal to check. In your terminal write

git --version

and you should get back your version number.

If you do not have git on your computer you may have to install it. For instructions on how to check and install git on your computer see this very helpful website or better yet this manual

Configure Git with your name and Github account email

This part is simply configuring Git with your name and the email associated with your Github account. You must use the same email that is associated with your Github account. The user.name doesn’t have to be the same as your Github username. You may want to just put your First Last name.

You can do this in one of two ways. First is by use of the usethis R package;

# install.packages("usethis")

library(usethis)
use_git_config(user.name = "First Last", user.email = "your_email@example.org")

The second way is through the terminal/shell/command line. In the terminal, run the following commands;

git config --global user.name 'Jane Doe'
git config --global user.email 'jane@example.com'
git config --global --list

Setting up your creditials with a Personal Access Token (PAT)

When we interact with a remote Git server, such as GitHub, we have to include credentials in the request. This proves we are a specific GitHub user, who’s allowed to do whatever we’re asking to do. PAT for HTTPS

It is easier to do this first so that you do not run into issues when you need to push and pull back-and-forth between RStudio and your Github repo.

Step 1 - Make sure you are logged in to your Github account on your browser.

Step 2 - Run the following code. After you do, your browser should pop up on Github on the page where you create a Personal Access Token (PAT);

# If not already installed, install these packages
install.packages("devtools", "gitcreds")

usethis::create_github_token()

• create the token in Github (in the browser)
• copy the PAT to your clipboard
• Leave the window open for the time being

Step 3

• Run this function in the console in RStudio;

gitcreds::gitcreds_set()

• A list of options should present in the console
• The output from the console in RStudio should look something like this…

> gitcreds::gitcreds_set()

-> Your current credentials for 'https://github.com':

protocol: https
host    : github.com
username: your_username
password: <-- hidden -->

-> What would you like to do?

1: Abort update with error, and keep the existing credentials
2: Replace these credentials
3: See the password / token

Selection:

Enter ‘2’ in the console and press enter.

• enter in the Personal Access Token from your clipboard (paste in the console)
• press enter.

You should be able to push your commits to your Github repo and pull from the repo down the RStudio project on your local computer now.

Setting up your project in R studio

Now that you have a github account, a local Git client on your computer, entered in your name and email to git config, and set your PAT for two-way communication with Github, you are ready to start working with git through R studio.

• First, copy the URL for the repository in your Github.
• Click on the green <> Code button to see the URL for the repo
• Copy the URL

• Open R-studio and start a new project.
• Choose a project with version control:

• Select the option to clone a repository from git.

• Paste the URL from the Github repo you copied earlier
• The project directory name should auto-populate with the same name as the Repo in Github
• Under Create project as a subdirectory of:, you can choose where the directory for this project/repo will be (Recommended that you keep the subdirectory on your local computer. You can run into problems if you place the project in a subdirectory on a cloud network directory (e.g., OneDrive, Dropbox).)

Quick re-cap: What R studio will then do is to clone the repository you created on github locally on your computer.

So that R-studio knows which github local repository to clone you have to specify an external url that matches your username and the name of the new repository that you just created on github (Repository URL).

You also have to specify where your local git files are going to be located see (Create project as subdirectory of:).

Hit the create button and R studio will create a project that should look something like this. Notice how the files replicate what is in the Github repo

In case you run into trouble at this stage - and are not able to connect your files make sure that your local credentials. To check this you can run the function edit_git_config() from the usethis R package. This will open up your .gitconfig file in RStudio. Ensure the email in your .gitconfig file matches the email you used to signup with Github:

library(usethis)
usethis::edit_git_config()

There should be no problems here since you already configured git with your name and email a few steps back.

If your git, github, and RStudio have no problems communicating you can set about modifying your local files at will, adding files and changing them.

Each time you add a new file in your local directory or change it in some way it will appear in your git tab like so:

• Notice that because I have not modified the README file that was imported from github this file does not appear in my git tab.

• Only new files or files that have saved changes will appear in the Git tab.

• You don’t have to commit and push all the files from the project on your local computer up to your Github repo.

• Anything listed in .gitignore will be kept away from Git and Github.

• Also note that Github won’t allow you to push files that are greater than a certain size (I think anything greater than 500MB, but I’m not sure).

• It may be good practice to store your data and large files in multiple places, preferably a cloud server (e.g., OneDrive, Dropbox, Google Drive, etc.) in addition to the RStudio project on your local computer.

Commit and Push files to Github Repo

The final step is to commit the changes I have made to my local files to the github repository. For this purpose I have to commit the files I want to update (I only commit the files I wish to update) and then I need to push them to the external repository.

To do this I first select the files that I want to commit. Next I hit the commit button.

When I hit the commit button another window pops up where I can write myself notes about the changes I am committing. Write something useful and brief that explains what you have done or should do next. - Green signifies what is new and will commit; - Red signifies deletion/changes made. - Review changes before you click commit

Once I hit commit R-studio knows which local files I want to change in my external depository. Note that I can work locally and commit many files and then work on other files and commit them later. Commit only commits changes to my files locally. The last step then is to push all my locally committed files to my external repository.

From within my project I simply push the green push button in my now empty git tab and my external repository is updated.

Github then tracks all of the changes in each file and new files added in each commit while also updating the main file.

This is very nice if you are working on a project - like a website that you might want to change frequently. You can simply open the project - make a change to any one part of the project and commit those changes to github. Imagine, for example, a website where you post new data and other information as it becomes available.

Optional: Sync a README.Rmd with README.md

The front face of your Github repo will usually display the README.md for your project. Although this isn’t technically a website, this is where the source code and files for your project will be housed (hence, repository). It’s often a good idea to include a description of your repository, long or short, both for yourself and others who may take interest (or who you’ve shared the link to your repo).

On this page you can include descriptions, links, examples, code, plots, images, and even gifs. This is best done by use of a RMarkdown file, README.Rmd that will sync with the README.md file upon redering (i.e., knitting in RStudio). This entire repo screen you’re reading now was written using this method.

• First, build a README.Rmd file
• The usethis::use_readme_rmd() function initializes a basic, executable README.Rmd ready for you to edit:

use_readme_rmd()
#> ✔ Writing 'README.Rmd'
#> ✔ Adding '^README\\.Rmd$' to '.Rbuildignore'
#> • Update 'README.Rmd' to include installation instructions.
#> ✔ Writing '.git/hooks/pre-commit'

In addition to creating README.Rmd, this adds some lines to .Rbuildignore, and creates a Git pre-commit hook to help you keep README.Rmd and README.md in sync.

Now you should have a README.Rmd file in the working directory of your project. When you want to update the README on Github (either for your project, an R package, or just for general information) you must only edit the README**.Rmd** and not the README**.md**. When you render the README.Rmd document file, it is hooked to the README.md so that changes in the first will also change in the second. Once you have edited the README.Rmd file to your liking, render the document (i.e., knit in RStudio), commit, and then push up to your Github repo. The front page of your Github repo should reflect your edits in the README.Rmd.

Exercise

• Install git on your computer

• Create a github account

• Create a version control project in R studio and pull documents from the github websit

• Add projects in R studio and upload them to the gihub repository (using commit and push)

• Working together in git.

One of the most useful things about github is the ability to work collaboratively.

Associating your RStudio with a collaborative project

First, in order to work collaboratively, you may need to associate your RStudio with a project in GitHub that you did not create. If you created the project, do the following to add collaborators:

Go on the Github website to Settings > Manage Access > Invite a collaborator.

Your teammate should accept the invite in their email.

Once this is complete, you can use the steps above to associate your RStuido with the GitHub project.

Pulling Changes

One important aspect of collaboration in Github is the ability to pull changes. This allows you to update your code to align with changes pushed by collaborators.

Using the down arrow button, RStudio goes to the GitHub repo, grabs the most recent code and brings it into your local editor. (Pulling regularly is extremely important if you’re collaborating, though if you’re the only one working on an RStudio project and associated GitHub repo, you know your local code matches what’s on GitHub so it’s less important.)

To pull, click the blue down arrow on your Git tab to see if you have changes to pull. If collaborating, you might run into merge conflicts.

When you pull your project updates to show the changes your collaborator has made to the project. Look at the dates.

and

You can also track the changes on github if you want more details.

Go to your github project:

There you see who are the collaborators and when each item was updated. For even more information click on any of the files (here the qmd file)

Here you see the history of the development of the project and if you want to see who made what changes when push the blame button.

The blame allows you to blame whoever - mostly yourself ;) is responsible for making changes to your project.

If you want more of an overview - then push the history button and you get a summary of changes:

In sum this is the workflow when you and your collaborator are both working on the main project and either one of you can make changes to the project.

When someone invites you to a project and to work on the main as here:

You can open the project locally as you would any other version control project (see earlier steps in the tutorial)

Once you are done changing your files locally - you then go through the same steps of committing and pushing. Which results in this message telling you the process was successful.

aand your changes will show up in the remote directory on github.

Branches

Sometimes you have a hierarchy - when one of you is the lead (author for example, or if you are working with an RA etc). where you want to review and approve any changes before they are made. In those cases you work with branches.

In order to create new branches, go to the ‘git’ tab on your RStudio console and click ‘new branch’.

You can then populate that branch the way you want and ask your associate to work on that branch only (your associate can also create a branch to be reviewed later)

Then click create and you have made the new branch.

You can see your branches like so:

Then simply create the new branch and you’re done.

If you click on the new branch, you will then see this as you switch:

This branch will initially not be published to the repo. You can publish it via the github website or the github desktop client.

You will then see this on your github page:

Exercises

Start a github project on the github website with some documents

Invite your partner to join

Pull your partner’s documents,

Edit the documents, commit the changes and push changes to their project

Troubleshooting unintended branches

If you try to push when you have not pulled changes that your collaborator has made on a main branch you get the following message:

If you try to pull before pushing changes that you have made to documents that your collaborator has changed you get the following warning

Here the program is creating branches for you so that changes are not lost. The solution to #1 is to pull before you start making ay changes to make sure you are working on the most up to date version. The solution to #2 when you both have made changes that need to be reconciled is to

1. Committ your local changes then you receive the following message:

then you pick from the options merge rebase and fast-forward

for a detailed explanation of the differences between the different options see for example this website

To employ the merge solution go to terminal and write:

then you can pull the document. Once you pull the document you can scroll through and see where your merger conflict occurred.

You then have to resolve this conflict save and now you can push.

Good git hygene

You can look to this article for other useful information for keeping good Git hygiene when collaborating.

Briefly the first four rules of thumb are:

Always Pull Before a Push

Pull frequently

Push infrequently

Commit Frequently

Additionally the article discusses optimal git branch for working together.

Merge “forward” frequently

Create Pull Requests Infrequently

To better understand these

Associating existing r studio projects with git

In order to associate an existing RStudio project with Git you will need to create a Git repository as described above and then follow the steps below.

#> ✔ Setting active project to 'C:/Users/isaia/Documents/R/git_tutorial'

You will then get a prompt asking if you want to commit the files you’ve already created to your repo. Select yes (option 1). You should then also see the git tab.

#> • Call `gitcreds::gitcreds_set()` to register this token in the local Git credential store
#>   It is also a great idea to store this token in any password-management software that you use
#> • Open URL 'https://github.com/settings/tokens/new?scopes=repo,user,gist,workflow&description=DESCRIBE THE TOKEN\'S USE CASE'

You will then get a number of options to select about what your token use case will be. This will be project-dependent.

You can learn more about the selections $$here$$(https://docs.github.com/en/developers/apps/building-oauth-apps/scopes-for-oauth-apps) to help guide you in your process.

#library(gitcreds) 
#gitcreds_set()

When prompted to enter a token or password, enter the token you just created. If you have entered one previously, you will be prompted to choose if you’d like to keep your credentials. If nothing has changed, select 1 and keep things as they are. If they have, follow the most applicable selection.

Optional: Github Desktop Client

A lot of problems can be resolved by examining the Github desktop client. It’s free and you can download it from the Github website.