practice-git

A repository setup to practice git

The purpose of this tutorial is to practice merging, branching, and rebasing.

To start the tutorial

git clone git://github.com/imintel/practice-git.git && cd practice-git

###Lesson one - Merging

##Setup

git checkout merge-1 && git checkout merge-2 && git checkout merge-3 && git checkout merge-4 && git checkout master

####Scenario

Clojure decided nil => null, but someone thought it was nil => pizza

  git checkout merge-1
  git merge merge-2

Make sure null is used.

Clojure decided to change ( => [ and ) to => ] , but someone on the team thought it was just $ signs

  git checkout merge-3
  git merge merge-4

Make sure [ and ] are used

###Lesson two - Workflows with rebase

  git checkout -b feature-1

The -b flag tells git to use a new branch.

Alternatively we could have done,

  git branch feature-1
  git checkout feature-1

feature-1 is a feature you have to implement.

Now make 4 - 5 commits, arbitrary changes are fine.

Now we want to get some commits into one commit because they are all referencing the same task within that feature-1.

We want to rebase back to the HEAD commit on master.

To see the head commit

git log master and copy the SHA of the top commit

Now we are ready to prepare feature-1 to be added to master.

  git rebase SHA_OF_MASTER_HEAD -i

The -i is for interactive mode

You should see your text editor popup! As a side note, if you want to change your default editor it is possible.

Assuming you are still have 'feature-1' checked out, the git log should look like the commits you "rebuilt" with rebase on top of the HEAD commit on master.

Now you are ready to bring your work over to master. I typically will use rebase again, but merge can also be used.

git checkout master
git merge feature-1

Under the hood this is what github pull requests do.

Alternatively, you can use rebase! But first when want to clear the commits we just added to master.

###Using git reset

git reset can be your best and worst friend at times if you don't know how to use the command.

For now, we are using it to get the commits off of master that we just merged from feature-1. git reset first param is a commit reference. That can be a SHA, HEAD, HEAD1, HEADn. For us, we are going to use the SHA of the head of master from earlier. We can also pass a flag to reset, --hard. The --hard flag clears all changes. By default, it uses --soft, which keeps the diff in the working tree.

  git reset SHA_OF_MASTER_FROM_BEFORE --soft
  git status

The git status will show you the changes from all of the commits that were "reset". We don't need these, so we will git stash.

Now lets add those commits to master from feature-1 with a rebase.

git rebase feature-1