colinta/git by colin.md

## git by colin.md

      
    Raw
  

              git by colin.md
            
          
    GIT OBJECTS

.git/objects
/f4/8011a40ba2f5b9f6af3b387e


This is the "heart" of git, but not the brains


key-value store (key == sha1!)


blobs


trees


refs

commits, branches, tag, HEAD


REWRITING HISTORY

Public or Private


private?  Go nuts!
git commit --amend
git push --force origin master
git rebase --onto origin/master


public?  Use merge!  It has benefits, I swear!


TORVALD'S OPINION

http://www.mail-archive.com/dri-devel@lists.sourceforge.net/msg39091.html

I want clean history, but that really means (a) clean and (b) history.


People can (and probably should) rebase their private trees (their own
work). That's a cleanup. But never other peoples code. That's a "destroy
history"


You must never EVER destroy other peoples history. You must not rebase
commits other people did. Basically, if it doesn't have your sign-off
on it, it's off limits: you can't rebase it, because it's not yours.

GOLDEN RULE OF REBASING

https://www.atlassian.com/git/tutorials/merging-vs-rebasing

REBASE THEORY

  * - * - A - B <- master
       \
        - C - D <- you are here

git rebase --onto master
git rebase master
* - * - A - B <- master
                     \
                      - C - D <- now you are here

Linear history is nice to have:
* - * - A - B - C - D <- you
            ^ master


REBASE MASTERY

git rebase -i master
reorder (not a command)


move important commits to beginning
cleanup/whitespace to end

fixup


squashes and uses first commit message

squash


squashes and preserves commit messages

edit


finicky!

remove


maybe not as useful
git rebase --abort
git rebase --cont
git rebase --skip


  MERGE THEORY

  * - * - A - B - master
       \
        - C - D <- you are here

git merge master
  * - * - A    -    B    <- master
           \         \
            - C - D - +  <- now you are here


merge commits are "nothing special" (but yes, they are)


traversing history through merge commits?  compare commits!
git log HEAD ^master  # only show MY history, nothing that is in master


REFLOG, FSCK

There Be Dragons


git reflog

Records HEAD changes


git fsck --lost-found

Is pretty cool


GIT FU!

aka git log


personal fav:

git log
  --pretty=format:'%Cred%h%Creset - %Cgreen%ci%Creset%C(yellow)%d%Creset %s %Cblue(%cn)%Creset'
  # --pretty=format:'%h - %ci%d %s (%cn)'
  --abbrev-commit
  --date=relative
  --graph

aliased to

git ll
git log -p
git log --stat
git log --author 'Colin'
git log --author 'steam\|process255\|sean'


GIT FU!

aka aliases

~/.gitconfig
git config --global alias.st status

Really common, highly recommended:

st = status
br = branch
ci = commit
co = checkout

alias g=git  # for the supremely lazy
g st
g co -  # checkout previous branch
g ci -am "your message here"  # commit all changes w/ commit message


GIT FU!

aka aliases

[alias]
  ignore = !([ ! -e .gitignore ] && touch .gitignore) | echo $1 >>.gitignore
  grab = ![[ -n "$1" ]] && git fetch origin $1:$1 || echo "You must specify a branch"

git ignore [file]
git grab master  # updates master, you don't change branches
# git fetch origin master:master
git rebase master

git my
# git log HEAD ^master

# all files being tracked
git ls-files

git diff --patience -w   # ignore whitespace
git diff --color-words   # show word changes (instead of line changes)
git diff --cached        # show changes *about* to be committed


LINKS!


https://git-scm.com/book/en/v2
https://www.atlassian.com/git/tutorials