teaching-git.mdown

Learn Git

Intro

• Talk about SCM in general
• Talk about distributed SCMs
• Talk about origins of git
  • created by linus b/c he was sick of perforce
• Git is more than SCM, it's a filesystem
• git init
• talk about .git (verses .svn being everyhere)
• Look at .git/config
• make a new file
• git status
• git add / git status again
• git commit / git status again
  • talk about small, atomic commits and why they're good
• git log
  • not linear, the repository "version" is an SHA1 hash
  • git log -p shows actual diffs

How Git Stores Files

• talk about how a refernce (the SHA1 hash) doesn't need to be the full hsah
• git show

Changing existing files

• change the tile
• git add the file (or commit with -a - but avoid that if you can)
• git log again / git log -p again

Adding yet another file

• git add
• git commit
• git log

Removing files

• file system rm

  • STILL need to stage that change (can use either ADD or RM confusing*)
  • UNSTAGE that change by using git reset HEAD file

• ASIDE: Talk about .git/HEAD and the concept of HEAD - it's JUST A POINTER TO A REF

• git rm

  • does two steps in one. Removes file from filesystem AND stages the change right away
  • undo it the same way, unstage with git reset HEAD , then git checkout -- file

Git add interactive

• Adding untracked files
• Staging tracked file changes

Customizing Git

• global options
• git config --global alias.st status
• format is "git config [--global] [section].[key] value"

Branching

• Branches are a way to explore different ideas
• they bring over unstaged/uncommited changes so you can work in master but decide to make a branch
• You can bring back your changes by merging
• Move to the branch you want to merge TO, then "git merge "
• conflicts
  • resolve on merge, then add the file to the staging area and commit to finish it off

Tagging

• Just a marker for a specific tree state
• Kind of like .git/HEAD
• see them in .git/refs/tags

Remotes

Cloning

• git clone pulls down a remote repository and sets all the stuff in .git/config
• git push pushes any commits the remote doesn't yet know about

Gist

• every pastie on gist.github.com is a repository
• I created a gist, made a file then pulled down that repo locally
• Made a local change, added/commited it, then pushed it up
• saw the change on the website

Forking Gists

• Duncan forked my gist
• Then he cloned from his private url (public urls are read only)
• Made a local change, added/committed/pushed
• I added duncan's public url as a remote on my repo: git remote add duncan git://gist.github.com/69665.git
• Merged in his changes (git merge duncan/master)
• Pushed back to MY gist.