1. Git <-> GitHub

2. git vs GitHub
git is a local software that manages a local version control repository and communications with remote repositories.
GitHub is a web service that provides storage and management of a remote git repository.

3. git documentation

4. Working with git Working with a remote repository remote push fetch
Working with the local repository
Init
status
add
commit
log
branch
checkout
merge
reset
config
Working with a remote repository
remote
push
fetch
pull

5. distributed version control system
The development environment with:
Working directory
Staging area or index
Local repository
A server with:
Remote repository

6. Cloning a repository
Working directory
Local repository

7. Making changes in the working directory
There are 2 types of files in the working directory:
Tracked: files that Git knows about.
Untracked: files that have still not been added, so Git doesn’t know about.

8. Updating the remote repository
As changes are ready in the working directory, they must be added in the staging area.
When there is a set of changes with a single purpose in the staging area, it’s the time to create a commit with a message about that purpose in the local repository.
When there are one or several commits in the local repository ready to be shared with the rest of the world, they must be pushed to the remote repository.

9. Different states of a file
Different states of a file in the development environment:
Modified
Staged
Committed.

10. Updating the development environment - Fetching
When executing git fetch, the data from remote repository only travels to the local repository.

11. Updating the development environment - Pulling
When executing git pull, the data from remote repository travel to 2 areas:
To local repository: fetch
To working directory: merge

12. Attributions https://git-scm.com/doc