part-2-branches.md

2. Merging branches

2.1 create a new branch called crazyidea

user@host project $ git branch crazyidea
user@host project $ git checkout crazyidea

2.2 run git status to make sure everything is OK

user@host project $ git status

It will state which branch is checked out, make sure it's crazyidea.

2.3 make changes

Modify both lines of file1.txt and add a third line:

Oxygens are red.
Nitrogens are blue.
In Cryo-EM everything is grey.

2.4 add and commit the changes

user@host project $ git add file1.txt
user@host project $ git commit -m "change to elements"

2.5 visualize the graph of commits

user@host project $ git log --all --decorate --oneline --graph

Each commit is one line. HEAD points to the commit that is checked out (the latest commit). The crazyidea branch points to the latest commit. The master branch is still pointing to second commit.

2.6 merge crazyidea to master

In this case, merging is equivalent to updating the master branch to point to the latest commit.

user@host project $ git checkout master
user@host project $ git merge crazyidea
user@host project $ git log --all --decorate --oneline --graph

2.7 create a new commit in a new branch beautify

user@host project $ git branch beautify
user@host project $ git checkout beautify

Change everything to all in the third line of file1.txt.

user@host project $ git add file1.txt
user@host project $ git commit -m "improve wording"
user@host project $ git status
user@host project $ git adog

2.8 go back to master and commit

user@host project $ git checkout master
user@host project $ git adog

Change grey to gray in the third line of file1.txt:

user@host project $ git add file1.txt
user@host project $ git commit -m "changed to gray"

2.9 run git log --all --decorate --online --graph to see the branching

user@host project $ git adog

2.10 Look at differences between specific commits

Consider the following commit graph

* 82e34e7 (HEAD, master) changed to gray
| * 8b3c5d6 (beautify) improve wording
|/  
* 362bffc change to elements
* 62fbfe6 roses to tomatoes
* 758fe9d initial draft of mock text

We can look at the differences between master and beautify with either of these two commands:

user@host project $ git difftool -t vimdiff master beautify
user@host project $ git difftool -t vimdiff 8b3c5d6 82e34e7

2.11 Merge

There will be conflicts, which need to be manually resolved.

Roses are red.
Nitrogens are blue.
<<<<<<< HEAD
In Cryo-EM everything is gray.
=======
In Cryo-EM all is grey.
>>>>>>> test

go to next part

part 3 - remotes