Git Guide for absolute beginners

Overview ##

1print("coding is <emotion>")

1print("coding is fun")

After we got this out of the way.

I’ll now explain the connection between Github and git: We first need to understand what exactly git is.

Git is a versioning tool, i.e. you upload changes you made to a project to have a kind of backup. You can use git to go back to a previous backup.

• commit: a backup, a part of the project, a version, a revision
• repository: a project or a collection of backups
• remote: the origin / url of the repository

Git is the tool that allows you to create commits, jump back to older commits and upload them. Github is the website that allows you to create and host repositories, manage them and much more, see here.

Many people, including myself, use Github to collaborate and share code with the world.

How to authenticate ##

To safely interact with out repository (which is hosted on github) from our local machine, we need to authenticate.

Lets go through a few settings and generate a token, which we will use to tell github its us whos trying to update the repositories:

1. Sign up for github or log into github

2. Click on the profile picture on the top right:

   

3. After getting into the settings we now scroll all the way down and click on developer settings:

   

4. Now we click on the personal access tokens toggle and select the Token (classic)->Generate new token (classic) option

   

5. In the next menu we input the name of the token (here: local machine), afterwards we set the expiration to none (github recommonds not setting this option, even though its very convient)

   

6. The next step is to select the permissions the token will hold (for this example we just allow read and write to repositories, note the small red box):

   

7. To finally create the token, scroll all the way down and hit the big generate now button:

   

8. Copy the created token by clicking on the button right next to the token

9. The 9th step contains a lot of stuff:

   Open a terminal and type the following commands:

 1# tell git to store your credentials indefinitly
 2git config --global credential.helper store
 3
 4# set your username exactly as the username you selected on github
 5# (replace <username> with your username)
 6git config --global user.name "<username>"
 7
 8# set your email exactly as the email you selected on github (replace with your username)
 9git config --global user.email "<example@example.com>"
10
11# view if everything is stored:
12git config --global --list
13# should output:
14# user.name=<username>
15# user.email=<example@example.com>

Creating a new repository on github ##

1. Navigate to your GitHub homepage (here)
2. Click on the profile picture in the top right corner and select Your repositories in the newly opened drop-down menu:

   

3. Once navigated to the repository overview we simply click on the green New button in the top right corner:

   

4. Now we input a repository name (Sub step 1), a description (Sub step 2), select whether or not to make the repo public (Sub step 3) and tell github if it should create a README file in our repository (Sub step 4). After that we hit Create repository (Sub step 5).

   

5. For the following chapter we need the url to the project, either copy it from the url bar or follow the quick 2 step guide:

   

   • click on the Code button
   • click on the copy icon button next to the url to copy it

Downloading (cloning) a project ##

To clone a repository, one has to know the url of the repository and pass it to the git clone subcommand:

1# clone your newly created project:
2git clone https://github.com/<username>/<project>
3# copy the following and paste the url from the previous chapter at the end (keep a space between clone and your url)
4git clone

After cloning there will be a new folder in your current directory and there will be output on your terminal similar to this:

• Newly created directory:
  • on linux: ~/<reponame>
  • on windows: C:/Users/<user>/<reponame>

Making changes ##

We will now modify the Readme.md created by hitting the check while creating the Github repository.

Open the README.md file in the directory on your system in any editor you want, for me its vim:

Make a change, save the file:

 1diff --git a/README.md b/README.md
 2index 9716b1d..fe185f3 100644
 3--- a/README.md
 4+++ b/README.md
 5@@ -1,2 +1,5 @@
 6 # Test-repo
 7+
 8 test repos description
 9+
10+this is a change / modification

Creating a commit ##

As i outlined in the introductory chapter a commit is a revision or a backup which we want to add to the repository’s history. This commit has a title and a list of changes which we made. A commits title should describe the changes made in it.

We modified the README and added a new paragraph, so we write exactly that in the commit title:

1# tell git what file to include in the commit we want to create
2# the -A flag tells git to include all modified files in the repo
3git add -A
4# git commit creates the commit with the changes we told it to include using git add
5# the -m flag tells git to set the following in "" as the commit message
6git commit -m "added new paragraph to readme"

The output of git commit highlights the changes we made as well as the commit title we specified.:

1[master a8fee7b] added new paragaph to readme
2 1 file changed, 3 insertions(+)

Uploading changes ##

To upload the commit we created we tell git to push:

1git push

Result:

Viewing the changes ##

After we made the changes, created a new commit and pushed it to the remote we can now go back to the web browser and reload the repository page:

• take a look at (1) which displays the last commit which was pushed to the remote, thats the commit we made
• now look at (2) which displays the change we made to the README.

Wrapping up: ##

You are now able to

• understand the basics of git and github
• authenticate to github using git
• create a new repository
• create a new commit
• upload / push this commit to the newly created repository
• view these changes and the commit on github