===== GIT =====

==== Overview ====

=== What is it? ===


  * Distributed VCS
  * Manages workflows of over [[https://www.linuxfoundation.org/wp-content/uploads/2020/08/2020_kernel_history_report_082620v2.pdf|10 commits per hour]]
  * Works best with textual content or source code
  * Ability to create/edit locally with tools you know
  * Self contained history and configuration in ''%%.git%%'' folder
  * Only up-/download need network

==== How does it work? ====


  * Similar to ''%%diff%%'' and ''%%patch%%'' utilities
  * Stores history in a compressed hash-based store
  * Current checkout is the regular directory structure
  * Saves meta information with every commit for traceability

===== GIT Commands =====

==== Get a repository ====

=== Create a new one ===

<code>
cd <REPO>
git init
ls -alh
</code>
=== Clone an existing one ===

<code>
git clone https://github.com/<USER>/<REPO>
cd <REPO>
ls -alh
</code>
==== Check the state it’s in ====

<code>
git status
git diff
git diff --cached
git log
</code>
Note: this may use the pager (''%%less%%''/''%%more%%'')

==== Get changes from others ====

Get changes from a specific remote, optionally integrating them into the current branch

<code>
git fetch <REMOTE> 
git pull <REMOTE>
</code>
You can always fetch the changes but pulling requires the local and remote branches to be somewhat aligned.


  * Pulling should be a ''%%fast-forward%%'' operation.
    * The current branch is a direct ancestor of the remote branch.
  * Ensures that pushing to the remote won’t introduce unrelated changes.

==== Push changes ====

<code>
git push <REMOTE> <BRANCH>
</code>
^Github/Gitlab                         ^Regular Git                              ^
|Changes are pushed to your account    |changes are pushed to a throw-away branch|
|Merged by using a PR/MR on the website|Merged manually if no conflicts arise    |
|Inspection by collaborators during MR |No inspection until deployed             |

> Do **NOT** push directly to ''%%master%%''!

==== Mistakes and Corrections ====

From safe to loosing all local changes since last commit:

<code>
git stash
git reset
git reset --hard
git checkout <CLEAN> && git checkout -B <BRANCH>
</code>
**Read the [[git-scm.com|manual]] before loosing more of your changes than you wanted to reset!**

===== Workflow =====

==== Workflow 1 ====

Highly dependent on project/organization! But:


  * use branches, don’t work directly on ''%%master%%''
  * try to work on one topic at a time
    * switch between branches when working on different parts of the project
    * create ''%%merge request%%''s for every branch, that’s done or ready for review
  * write consice ''%%commit message%%''s

==== Workflow 2 ====

Combined like this is a good way to start working:


  * Start by syncing the progress of upstream

<code bash>
git checkout master
git pull origin
git checkout -b addGitTalk
</code>
  * Work on your changes to the project
  * Add new code followed by

<code bash>
git diff
git status
git add [PATH]
git diff --cached
</code>
  * Repeat the two previous step or publish

<code bash>
git commit
git push
</code></blockquote></HTML>
==== Work on a feature ====

  - Create a new branch, which starts out identical to the current
  - Work on the project
  - Mark your changes as ready
  - Check if all the changes look good and are marked for inclusion in the next commit
  - Add your changes to the branch inside the repository

<code bash>
git checkout -b <NAME>
...
git add [PATH]
git diff; git diff --cached
git commit
</code>