Effective Git

Transcript

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   If that doesn't fix it, git.txt contains the phone number

   of a friend of mine who understands git. Just wait through a few minutes of 'It's really pretty simple, just think of branches as...' and eventually you'll learn the commands that will fix everything.
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   EFFECTIVE GIT Michael Cordell

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   GIT: THE BASICS git is a distributed version control system

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   EDITING class Startup def increase_roi step_one step_two “????” profit! end

   end
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   STAGING ƭ startup.rb git add startup.rb Index

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   COMMITTING ƭ startup.rb Index git commit -m “Add the startup!”

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   ƭ ƭ ƭ ƭ

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   BRANCHING master git checkout -b feature feature

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   BRANCHING master feature git commit

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    BRANCHING master feature git commit

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    BRANCHING feature git checkout master master

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    BRANCHING feature git commit master

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    BRANCHING feature git merge feature master

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    WHY

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    Code Editor || IDE VCS Build Tools

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    Build Tools Editor/IDE Now VCS

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    Since git deals with history, git’s effectiveness as a tool

    is directly related to how it has been used in the past
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    GUIDING PRINCIPLES

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    Short, focused commits

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    Short, focused commits

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    Meaningful commit messages

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    KEY GIT PROPERTIES

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    GIT HISTORY IS A GRAPH

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    git history is a directed acyclic graph

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    git history is a directed acyclic graph

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    git history is a directed acyclic graph X

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    Commits in git are immutable

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    Commits in git are immutable Attempting to change: • Message

    • Content (file objects) • Parent commit results in the creation of a new commit
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    In contrast, references in git are cheap and movable

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    IN PRACTICE

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    IN PRACTICE: CONFIGURATION Learn to use aliases for faster git

    commands In your shell config: In your ~/.gitconfig $ git status $ g s
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    IN PRACTICE: STAGING git add -p not git add .

    Use editor plugins for easy staging by hunk or line
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    IN PRACTICE: COMMITTING First line is capitalized, short (50 chars

    or less) summary Second line is blank Rest of commit message should explain why and other useful information about the change See Tim Pope’s blog post on commit messages
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    RE-WRITING HISTORY

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    AMENDING git commit --amend alias cam = git commit --amend

    --no-edit
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    REBASING master feature git merge feature

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    REBASING master git reset --hard HEAD~1 feature

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    REBASING master feature git checkout feature

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    REBASING master feature git rebase master

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    REBASING master git rebase master

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    REBASING git rebase master master

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    REBASING git rebase master master feature

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    master feature master feature f87cb a98fc cc47a 18dd2 744ee 8ca01

    8ca01 ac871 ac871
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    master f87cb a98fc cc47a 18dd2 744ee 8ca01 feature ac871 git

    checkout feature
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    f87cb cc47a 18dd2 8ca01 ac871 master a98fc 744ee feature git

    reset --hard f87cb
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    INTERACTIVE REBASE git rebase -i master

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    rebase conflicts are the same as merge conflicts, resolve and

    git rebase -i master
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    git diff against the pre-rebase commit if you are worried

    about conflict mistakes
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    USING THE HISTORY

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    IN PRACTICE: BLAMING Use git blame to find why a

    line changed -w flag to ignore whitespace changes
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    GIT BISECT FOR BUG HUNTING master

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    GIT BISECT FOR BUG HUNTING master

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    GIT BISECT FOR BUG HUNTING master git bisect start

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    GIT BISECT FOR BUG HUNTING master git bisect good HEAD~7

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    GIT BISECT FOR BUG HUNTING master git bisect bad master

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    GIT BISECT FOR BUG HUNTING master git bisect

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    GIT BISECT FOR BUG HUNTING master git bisect bad

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    GIT BISECT FOR BUG HUNTING master

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    GIT BISECT FOR BUG HUNTING master git bisect good

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    GIT BISECT FOR BUG HUNTING master

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    GIT BISECT FOR BUG HUNTING master git bisect bad

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    MOVING/COMPARING CODE git checkout diff reset REF { }

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    MOVING/COMPARING CODE git checkout diff reset REF { } switch

    to that reference
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    MOVING/COMPARING CODE git checkout diff reset REF { } compare

    current against that reference
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    MOVING/COMPARING CODE git checkout diff reset REF { } get

    the files at that reference
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    MOVING/COMPARING CODE git checkout diff reset { }REF

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    MOVING/COMPARING CODE git checkout diff reset REF -- FILES {

    }
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    FIXING “MISTAKES”

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    In git, nothing added is ever “lost”

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    FIXING A BAD MERGE Usually this is as simple as

    backing the commit out by reseting one commit back git reset --hard HEAD~1 If you want to just fix a single badly merged file checkout the file you want git checkout GOOD_REF -- file
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    REFLOG FOR EVERYTHING ELSE git reflog keeps a reference of

    reach change in the HEAD reference (checkouts, rebase, cherry-picks, etc.) find the commit from before the change you want to fix and reset/checkout against it reflog expires after 90 days, but you can turn this off and have it never expire
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    git checkout diff reset b73c8c7 { }

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    LOST A STASH? git fsck can be used to find

    files that were at one time staged or perhaps stashed and dropped
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    REMOTES

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    REMOTES master

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    REMOTES master origin/master git pull

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    REMOTES master origin/master git pull

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    REMOTES master origin/master git pull

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    REMOTES master origin/master git pull

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    If you are going to force push prefer: git push

    --force-with-lease
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    End

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    FURTHER READING Think Like a Git Hartl’s Free eBook Cook’s

    Git from the inside out