Git and GitHub

Git: Commands

• Create Repo
  • git init initial a folder as a new repo, tracking all modification under it
    • .git/config configure only for this repo
  • git clone <path> [<new dir name>]
    • cannot create nested repo, so do check your pwd
  • git status
• Review Commits
  • git log for commit history
    • git log --oneline show only 7 characters of SHA and commit
    • git log --stat show files changed for each commit
    • git log --patch or git log -p show the detailed changes of each commit
    • git log -w ignore the change of blank when showing patch info
    • git log <7 character of SHA> start from particular commit
  • git show show commit with knowing SHA
    • share all arguments of git log
• Make Commits
  • git add
    • git add . to stage all folders and files
    • git rm --cached <file> to unstage
  • git commit open default editor
    • git commit -m "commit message" for short commit with only message
    • Rules of writing commits
      • Message: explain the role of submission
        • Good: “Update the footer to copyright information”
        • no why / no how / no and
      • Description: skip a line after message then start
  • git diff show changes of unstaged files
  • .gitignore file under repo to ignore specified files
• Develop on Branches
  • git tag show tag
    • git tag -a v1.0 [<SHA>] create a tag “v1.0” with comments (creator / date / message) for (optional) particular commit
    • git tag -d "v1.0" remove tag “v1.0”
    • use git log to verify the location of tag (use --decorate in older version)
  • git branch show all branches
    • git branch <branch_name> [<SHA>] create a new branch at (optional) particular commit
    • git branch -d <branch_name> delete branch (inactivate) w/o commit
      • to delete branch with commits, use -D instead
  • git checkout switch HEAD pointer to a branch, making it as active branch
    • convert file version to latest version of active branch (it replace all files under commit in previous branch, with that in the new branch)
    • git checkout -b <new_branch_name> <create_on_which_branch> create a new branch and checkout it
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  • git log --oneline --graph --all shows all branches and commits, also relationships
  • git merge
    • git merge <other_branch> merge a branch into current branch, like master
      • Fast-forward: moving HEAD to the latest commit (merge social-links to master)
      • Auto-merge: create a commit and merge (merge sidebar to master)
      • Merge conflicts: same row has been differently modified in both branches
        • git stop merging and return a single file, combining conflicting portions from both files, showing conflicts with indicators
        • update the file and commit it, then merge is completed automatically
        • you can just commit it and let merge done, but the conflicts will show in your file
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    • git reset --hard HEAD^ cancel merge
• Undo Changes
  • git commit --amend alter the most -recent commit
    • git add and run git commit --amend to add new files into last commit
  • git revert <SHA> create a new commit reversing given commit
  • Commit Reference
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  • git reset erases commit
    • git reset --mixed HEAD^^ move HEAD back to HEAD^^, and move changes of HEAD^ into working dir (default)
    • git reset --soft HEAD^^ move changes back to stage
    • git reset --hard HEAD^^ delete changes
    • Backup strategy
      • before any reset operation, git branch backup
      • after reset, if want to back to the starting point
        • git checkout -- index.html remove uncommited change to file “index.html”
        • git merge backup

Git: Shell Setting

1. Lib of Setting optimized for Git
2. Udacity style

GitHub: Remote Repo

• git remote show shortname of remote repo
  • git remote -v show detailed info
  • git remote add <shortname> <repo_link> add in repo link and its shortname
• git push <remote_shortname> <remote_branch> push all your local git info to remote repo
  • after push , git log will show the commit location of remote-tracking branch
• git fetch <remote_shortname> <remote_branch> download remote info and move remote-tracking
• git pull <remote_shortname> <remote_branch> fetch and merge with local branch
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GitHub: Collaborating with Fork

• git shortlog show commits under different collaborator
  • git shortlog -s -n show the number of commits only, sorted by large to small
• git log --author="Paul Lewis" show commits made by Paul Lewis
• git log --grep="bug"
• How to contribute?
  • Fork the repo
  • Check CONTRIBUTION.md
  • To contribute large effort, use Issues to communicate with project maintenance before starting
  • Create branch with clear name meeting requirement
  • Create clear, frequent and small commits
  • Pull request

GitHub: Keep Updated to Remote Repo

• Pull Request

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• Fetch and Pull from Upstream

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• git rebase transfer commits onto a new base

  • git rebase -i HEAD~3 squash last three commits interactively (refer to YouTube for detailed setting)
    • need force git push due to deleting commits
  • Backup strategy: create backup branch before rebase
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