git_2.md

Git 2

Summarizing yesterdays Git lecture

Creating a Github account and repository

• Online

Connecting local git with Github

• $ git config --global user.name "John Doe"
• $ git config --global user.email johndoe@example.com

Cloning a remote repository from Github

• git clone <repository-url> Copy an existing repository from a remote location (for example GitHub)
• git remote View and manage remote repositories
• git init Create a new repository locally

Commiting changes from your local repository

• git status Show which files are modified locally or new
• git add <filename> Add a file to change tracking and stage
• git commit -m "<message>" Make changes permanent

$ git add --all
$ git add <filename>
$ git commit -m "added a new feature some files changed"

Synchronizing remote with local repository

• git pull origin <branch> Fetch the commits from a remote repository and merge them with the current working directory (i.e. does a fetch and a merge in one)
• git push origin <branch> Push the commits from the local repository to a remote repository
• git fetch origin <branch> Fetch the commits from a remote repository into the local repository
• git merge origin <branch> Merge the commits from the local repository with commits fetched from a remote repository (actually this works on branches; this will be explained in the git tutorial part 2)

ToDo 1

• Create a new Github repository (Github UI)
• Clone it to your local machine (CLI)
• Create or edit the file README.md (Atom editor)
• Run the git circle to synchronize these changes with the Github remote repository. (CLI)

How to work with branches

What you think Git is:

What Git really is:

Command	Description
git branch -a	Show all the branches in your local repository
git branch -a -v	Show all the branches and their last commits
git branch <name>	Create a new branch based on the last of commit of the current branch
git checkout <name>	Switch from one branch to another
git checkout -b <name>	Create a new branch and switch to it
git stash	Temporarily move changed files out of the way
git stash apply	Reapply changes that were stashed previously

ToDo 2

• Create a new branch locally (CLI)
• Switch to this new branch and make changes to README.md (CLI and Atom)
• Run the git circle to synchronize these changes with the Github remote repository. (CLI)

Fixing upstream issues of a new branch:

git push -u origin newBranch

the "-u" flag sets the correct upstream URL to update Github.

How a merge works

Command	Description
git merge <branch>	Merge commits from one branch into the other.
git merge --abort	Abort a merge

Find Branches on Github

Merge Branches by creating a pull request

Review commits, create title for merge (resolve merge conflicts if necessary)

• Make sure you do not have uncommitted changes.
• If so, stash them or commit them
• Check that you are in the right branch with $ git status.
• If not do git checkout
• Do $ git merge <branch>
• $ git push

How to resolve a merge conflict

nano editor main commands:

You type	What happens
Ctrl+S	Save current file
Ctrl+O	Offer to write file ("Save as")
Ctrl+X	Close buffer, exit from nano

Nano cheatsheet

vim is the default editor in Git (on all operating systems). When a merge conflict occurs you are taken into vim to resolve it. The most important vim commands are:

You type	What happens
Esc	enter command mode
i	enter insert mode
:wq	write your changes and quit
:q!	cancel (quit without writing changes)

The use of the escape key in Vim, the i for insert mode, :wq and :q! to cancel

Forking repositories

• Log in to Github
• On Github fork the NEH Institute Materials 2017 repository
• Clone you fork to your local machine. In your Workspace directory in your home directory do: $ git clone https://github.com/acdh-oeaw/Teaching_CBS4DH.git
• On your local machine add the original repository as a second remote repository called upstream

$ git remote -v
origin  https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)
origin  https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)

$ git remote add upstream https://github.com/Pittsburgh-NEH-Institute/Institute-Materials-2017

$ git remote -v
origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)
origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)
upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git (fetch)
upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git (push)

Pull requests: making changes and submitting a pull request

• Create changes
• Track changes
• Commit changes
• Push commits
• Create pull request on github

Notes

• A fork is a remote repository on GitHub.
• Forking has to do with permissions.
• Explain difference between a fork and a branch
• A fork is not a branch, a fork is a repository, a branch is a series of commits.
• Explain git status "ahead / behind origin/master" line
• Explain difference between a pull and a fetch
• The Git pull command is not the same as a pull request on GitHub.
• Git does not track empty directories or empty files.

Terms learned part 2

• Fork (GitHub term)
• Pull request (GitHub term)
• Branch
• Merge, merge commit, merge conflict

Git Terms Cheat Sheet

• https://www.keycdn.com/blog/git-cheat-sheet

Github Actions

Please open this link to read more: Understanding GitHub Actions

Example Workflow to deploy Github Pages

• Requires directories: .github and a sub directory workflows in your Github (git) repository
• Requires a file called build.yml stored in the workflows directory

Inside build.yml

name: Build and publish

on: 
  push:

jobs:
  build_pages:
    name: Publish as GitHub Pages Website
    runs-on: ubuntu-latest
    steps:
    - name: Perform Checkout
      uses: actions/checkout@v2
    - name: Deploy GH Pages
      uses: peaceiris/actions-gh-pages@v3
      with:
        github_token: ${{secrets.GITHUB_TOKEN}}
        publish_dir: ./html

Learn more about secrets.GITHUB_TOKEN: Understanding GitHub automatic token authentication