Why learn git?

http://explainxkcd.com/wiki/index.php/1597:_Git

Install git

Windows

• Install git (with bash)
  https://git-scm.com/download/win
• Install Cmder
  https://github.com/cmderdev/cmder
• Install Cygwin
  https://cygwin.com/install.html

Mac

Comes pre-installed

Linux

Should come pre-installed

• Debian-based

  sudo apt-get install git-all

• Fedora variant 

  sudo yum install git-all

Initialize repository

$  git init [project-name]

creates a new Git repository

* if repo does not already exist

re·pos·i·to·ry

noun

• a place, building, or receptacle where things are or may be stored.
• COMPUTING 

  a central location in which data is stored
  and managed.
  "the metadata will be aggregated in a repository"

git clone

Copies existing repository files to your machine

NOTES:

• Will create a new folder with the repo's name
• Requires an existing repo

$  git clone [url]

Adding & Removing Files

Add or remove files to a
"staging index" for commiting

$  git add [file]

$  git rm [file]

$  git add .

Shortcut to add all
changed files

Question:

why use                               instead of                             ?

git add .            git add *

$  git commit -m "[message]"

Commit your changes

Saves a snapshot of the changes ("delta")
made to your files and when.
The message should be relevant and significant.

C0

C1

A Visualization

https://explainxkcd.com/wiki/index.php/1296:_Git_Commit

Ignore some stuff

Let git forget about and ignore non-critical files.

$  touch .gitignore

$  git add .gitignore

$  git commit -m "Add gitignore"

What is non-critical?

• development config files
• log files
• 'secret' files
• mock data

• thumbnails

  • Thumbs.db, .DS_Store, ._*

• IDE config files

  • *.sublime-workspace, *.idea/

Question:

why use                       instead of                       ?

git add .           git add *

Push your changes

Update remote repo with associated changes

$  git push

Push implicitly points to master

You could specify where to point your changes to

$  git push origin master

$  git push -u origin otherremote

but you probably will never need to.

Get what has changed

This changes your local files.

$  git pull

                    implicitly does a                         and then

git pull              git fetch         git merge

Check what has changed

Reports what changes have been made to the remote.

This does not change your local files.

$  git fetch

Branch out

Branch early, and branch often!

$  git branch new-branch-name

Simply points to a specific commit from history.

Default branch is called                 

master

$  git branch -b newbranch

is shorthand for

$ git branch newbranch
  $ git checkout newbranch

checkout switches to the specified branch and updates the working directory

C0

A Visualization

C1

C2

B1

Merge back in

$  git merge other-branch

Simply points to a specific commit

Create a new branch, develop a new feature,
and combine it back in

C0

A Visualization

C1

C2

B1

But... not everything
goes smoothly

$  git merge other-branch

 If the same part of the same file changed differently in the two branches being merged, Git can't merge them cleanly

Merge conflicts need to

be resolved

Git adds conflict-resolution markers so you can identify

them and manually resolve those conflicts

<<<<<<< HEAD:index.html
<div id="footer">contact : support@email.com</div>
=======
<div id="footer">
 please contact us at support@email.com
</div>
>>>>>>> newbranch:index.html

Merge conflicts need to

be resolved

Once resolved, simply commit  to finish the merge...

<div id="footer">contact us at support@email.com</div>

$ git commit

Merge branch 'newbranch'

Conflicts:
    index.html
#
# It looks like you may be committing a merge.
# If this is not correct, please remove the file
#    .git/MERGE_HEAD
# and try again.

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# On branch master
# All conflicts fixed but you are still merging.
#
# Changes to be committed:
#    modified:   index.html
#

Feature Branch

master

master

feature 1

feature 2

master

feature 1

feature 2

Protip: Merge master into feature, and then feature back to master.

New repo

• git init

• git remote add https://...

• git add .

• git commit -m "msg"

Existing repo

• git clone https://...git

• Make some change to a file

• git add .

• git commit -m "msg"

Hands on

Git config

$ git config --global user.name "John Doe"

$ git config --global user.email "e@mail.co"