Objectives

• Define "Version Control"
• Define crucial git vocabulary words
  • repository
  • staged / unstaged
  • commit / history
  • remote
• Use git from the command line
  • git init
  • git add
  • git commit
  • git push

Version Control

Version control is a term used to track and manage changes to a "codebase" over time.

For now, imagine a single file called C:

C1

C2

C3

C4

time

Version Control

C1

C2

C3

C4

time

With version control, we can view the differences between this file at different time points. This helps us understand the history of a codebase.

Version Control

C1

C2

C3

C4

time

Imagine the 4th version of this file contains an error.

Version Control

C1

C2

C3

time

With version control we can roll that change back to the previous working version.

Version Control

• Define "Version Control"
• Define crucial git vocabulary words
  • repository
  • staged / unstaged
  • commit / history
  • remote
• Use git from the command line
  • git init
  • git add
  • git commit
  • git push

Repositories

Lets create a situation like this now.

Make a directory and use git to make it a git repository.

$ cd ~/Desktop
$ mkdir tmp
$ cd tmp
$ git init
$ git status

Repositories

We just initialized a git repository. What is this thing?

• Repositories are folders.
• Everything inside this folder is under "version control" now, managed by git

# Try this:
$ ls -la

drwxr-xr-x   3 Tyler  staff  102 Apr 14 16:01 .
drwx------+ 19 Tyler  staff  646 Apr 14 16:00 ..
drwxr-xr-x  10 Tyler  staff  340 Apr 14 16:01 .git # WHAT IS THIS?!

$ cd .git
$ tree

Repositories

That folder named .git is a hidden folder

That folder contains the history information for this repository.

Try this:

$ rm -r .git
$ git status

Without a .git folder, we don't have a repo

Repositories

• Define "Version Control"
• Define crucial git vocabulary words
  • repository
  • staged / unstaged
  • commit / history
  • remote
• Use git from the command line
  • git init
  • git add
  • git commit
  • git push

Repositories

Reinitialize our folder to be a repository and make a javascript file

$ git init
$ touch helloWorld.js
$ git status

Now we want to "stage" our changes for the a "commit"

$ git add helloWorld.js
$ git status

Repositories

• Define "Version Control"
• Define crucial git vocabulary words
  • repository
  • staged / unstaged
  • commit / history
  • remote
• Use git from the command line
  • git init
  • git add
  • git commit
  • git push

Repositories

The final step in creating a "version" is to use the commit command

$ git commit -m "Useful message"
$ git status
$ git log

Now this commit is part of our history, which we can view with the git log command.

Remotes

• Define "Version Control"
• Define crucial git vocabulary words
  • repository
  • staged / unstaged
  • commit / history
  • remote
• Use git from the command line
  • git init
  • git add
  • git commit
  • git push

Remotes

So far, our history lives in that .git folder.

We'd like to use the internet to backup our work, as well as share our work with collaborators!

Enter: GitHub

Remotes

Lets walk through creating a new public remote repository on github!

www.github.com

A Metaphor

As we've seen, in git changes roll through several stages

A useful metaphor is to imagine git as a rocketship, and github as mars.

Mars Needs Supplies

Clean Socks!

Mars Needs Supplies

Clean Socks!

$ git add socks

Mars Needs Supplies

Clean Socks!

$ git commit

Mars Needs Supplies

Clean Socks!

$ git push

Mars Needs Supplies

Clean Socks!