Repository

Create a new repository on the command line

echo "# Github" >> README.md
git init
git add README.md
git commit -m "first commit"
git branch -M main
git remote add origin https://github.com/username/Repository.git
git push origin main

Push an existing repository from the command line

git remote add origin https://github.com/username/Repository.git
git branch -M main
git push origin main

When creating a file and then uploading to Github

create file.txt
git add -A   | git add file.txt
git commit -m "message"
git push origin main

Credentials

1. Create token classic at your settings
2. Grab and copy de Token
3. Install GCM - Github credential manager
   Linux deb package (ubuntu):

   sudo dpkg -i <path-to-package>
   

4. Run the following command:

   git config --global credential.helper store
   

5. When doing git push origin main enter your credentials:

   Username for 'https://github.com': username at github.com
   Password for 'https://username@github.com': [Paste the Token]
   

6. Your credentials now are stored in the system
7. Repeat git push origin main, and credentials will be not required now on.