repos, GUI, issue trackers, workflows, wikis, milestones, kanban, API, ...
   tutorial guide book parable dangit missing
      clone, pull, status, add, commit, push, merge, branch, fork, pull request, ...
   Bash commands scripting
      ssh-keygen -t rsa -f keyname -C "user@emailaddress"
      Windows Subsystem for Linux
      Git Bash
      Debian Ubuntu Xubuntu
      Chromebook Raspberry Pi

distributed version control system
   maintains version history
   merges changes between and within files
   peer-to-peer development
   remote server file system management

mistakes you may make
   key path, permissions
      chmod go-rwx ~/.ssh/key_name
   server port, key
   network connection blocking non-standard ports
   check what you're going to commit before doing it
      git status
   pull and merge before pushing
   refresh browser after editing page
   wait for server runner to finish
   use relative rather than absolute links to files
   avoid spaces and non-ASCII characters in paths, they need to be escaped
   don't use special characters in file names (Windows doesn't allow colons, Linux doesn't allow ampersand, ...)
   distinguish upper vs lower-case
   all content in repo (except for files that are too large to compress)
   archive size
      check size before commit
         du ncdu
      compress, resize pictures for Web
         ImageMagick, GIMP
         JPG: compressed, PNG: uncompressed
      compress, encode vidoes for Web

         name = your name
         email = you@email
      (lots of other options)
      host config_name
         hostname machine_name
         user user_name
         port port_number
         identityfile ~/.ssh/key_name
   .gitignore, .git/info/exclude 
      untracked files/directories to ignore
      script to run after a merge (which happens after a pull)
      script to run after receiving a push

   git help
      get help
   git config --list
      list config
   git config --system
      system config
   git config --global
      user config
   git config --global "Firstname Lastname"
      set name for commits
   git config --global "address@site" 
      set email for commits
   git config --global push.default simple
      default push only the current branch
   git config --global fetch.prune true
      locally prune branches that are remotely deleted
   git config --global core.editor vim
      set the editor
   git config --global merge.tool meld
      set the merge tool to meld
   git config --global pull.rebase true
      rebase rather commit automatic merges
   git config --global receive.denyCurrentBranch updateInstead
      update remote after push
   git config --global core.sharedRepository 0640
      default access group read
   git config --global core.autocrlf true
      configure Windows to use Linux/OSX line endings
   git init
      initialize a repository
   git init --bare
      initialize a bare repository
   git clone path_to_repo
      clone a repository mounted in the file system
   git clone user_name@machine_name:repo_name
      clone a repository with a SSH login
   git clone config_name:repo_name
      clone a repository with a SSH name config in ~/.ssh/config
   git remote -v
      list remotes
   git remote set-url origin URL
      set the origin remote
   git remote add name URL
      add a remote
   git pull
      fetch and merge changes
   git push
      push changes
   git push -u origin branch_name
      push a branch to origin
   git push --mirror
      mirror a repo
   git status
      report the repository status
   git add .
      stage all changed files to commit
   git commit -m "commit message"
      commit changes
   git commit -a -m "commit message"
      stage and commit changes
   git log
      show history
   git reflog
      show reference updates
   git log --name-status
      show names and status of changed files
   git log --graph --oneline --stat
      compact history view with graph and changes
   git rm
      remove a tracked file
   git mv
      move a tracked file
   git revert
      undo a commit
   git clean -f
      remove untracked files
   git reset --hard
      undo uncommitted changes
   git reset --hard origin/master
      reset to match remote
   git reset HEAD@{index}
      reset back to index
   git checkout -b branch_name
      create new branch
   git checkout branch_name
      checkout branch
   git push -u origin branch_name
      push new branch
   git merge branch_name
      merge branch
   git merge --squash branch_name
      merge branch, squashing its commits
   git mergetool -t meld
      resolve a conflicted merge with the meld GUI
   git checkout --ours .
      checkout existing files during merge conflict
   git checkout --theirs .
      chekout new files during merge conflict
   git branch -a
      list branches 
   git branch -d branch_name
      delete local branch
   git push origin --delete branch_name
      delete remote branch
   git fetch -p
      locally prune deleted remote references
   git tag
      assign a tag to a commit
   git blame
      show revisions of file lines
   git diff
      show changes between commits
   git diff commit1 commit2
      show changes between commits
   git diff branch1 branch2
      show changes between branches
   git submodule add path_to_repository
      nest a repository
   git clone --recursive
      close a repo including submodules
   git submodule update --init
      initialize and update submodules
   git submodule update
      update submodules 
   git submodule update --remote
      update submodules to remote  
   git subtree add -P path_in_repo remote_repo master --squash
      add a remote repo as a subtree
   git subtree pull -P path_in_repo remote_repo master --squash
      pull from a remote repo into a subtree
   git archive --format=tar --remote=repo_path HEAD | (tar xf -)
      copy the working tree of a repo
   git lfs track file
      extension for versioning large files
   find . -type d -name ".git" -exec bash -c "cd {}/..; echo ''; pwd; echo ''; git add .; git status; git commit -a -m 'find git'; git pull; git push;" \;
      recursively update all repos under a directory

   alias ga="git add ."
   alias gap='git add .;git commit -a -m "wip";git push'
   alias gb='git branch -a'
   alias gbcreate='git checkout -b'
   alias gbdelete='git branch -d'
   alias gbpush='git push -u origin'
   alias gbpushdelete='git push origin --delete' 
   alias gc="git commit -a -m"
   alias gcw="git commit -a -m 'wip'"
   alias gd="git diff"
   alias gf='git pull'
   alias gk='git checkout'
   alias gko='git checkout --ours'
   alias gkt='git checkout --theirs'
   alias gl="git log --name-status --graph"
   alias gm='git merge'
   alias gms='git merge --squash'
   alias gp='git commit -a -m "wip";git push;git status'
   alias gr='git reset --hard; git clean -f'
   alias gs='git status'
   alias gt='git push'