intro to git
TRANSCRIPT
introduction to
and
GIT COMMITS
local files
the staging area
first commit
second commit
parent
just a “patch”of what actually
changed
third commit
parent
parent
unique identifiers (sha)
ab67d9c
40fc3a7
be89a10
multiple parents and children = source graphs
branching out
ab67d9c
40fc3a7
be89a10
5e94ba2
f3c091d
merging back
ab67d9c
40fc3a7
783ad20
5e94ba2
f17cc43
WORKING WITHREMOTES
MASTER(by convention)
your computer github (a.k.a “origin”)
master master
Github is moving along...
your computer github
master
master
your computer github
master
master
let’s update our local copy
$ git fetch origin master
your computer github
master
masterorigin/master
$ git status -uno
Your branch is behind 'origin/master' by 2 commits and can be fast-forwarded
$ git merge origin/master
your computer github
master origin/master master
Fast-forwards are easy :)
Now another case...
your computer github
master master
your computer github
master
master
your computer github
master master
let’s update our local copy
$ git fetch origin master
your computer github
master mastero/m
$ git status -uno
Your branch and 'origin/master' have diverged,
and have 2 and 2 different commits each
$ git merge origin master
your computer github
master
o/m master
this created a new “merge” commit
we need to send it back to Github
$ git push origin master
your computer github
master masterorigin/master
but I don’t like merge commits!
your computer github
master mastero/m
$ git rebase origin/master
your computer github
x
origin/master master
your computer github
x
masterorigin/master
your computer github
master
masterorigin/master
we’re back to a linear history!
$ git status -uno
Your branch is ahead of 'origin/master' by 2 commits
$ git push origin master
your computer github
master masterorigin/master
careful: we actually re-wrote history!
only do this if no one has seen your commits yet
BRANCHES
your computer
master
$ git checkout -b foo
it's just a pointer
foo HEADmaster
HEAD is a pointer to where you are
working on your branch
foo HEAD
master
$ git checkout master
back on master…
foo
HEAD master
and working some more
fooHEAD master
and what about our remotes?
foomasterorigin/master
the origin doesn’t know about "foo"
$ git push origin foo
so “master” was just another branch!
origin/foofoomasterorigin/master
now while we’re on master
$ git merge foo
foo
HEAD master
looks familiar?
yes, that’s a merge commit
$ git branch -d foo
we just deleted the branch pointer
HEAD master
PULL REQUESTS
asking the “owner” to merge a set of your commits
(typically a given branch)
this branch is ready for review / integration
master my-branch
merged!
master“merged
pull request”
what if there is a conflict?
$ git checkout my-branch
resolve it on your branch
master my-branch HEAD
$ git merge master
first: resolve it
master
my-branch HEAD
“resolved conflict”
“mergedpull request”
master
“resolved conflict”
or we could have rebased to avoid the extra
“resolve conflict” commit
FORKS
you might not have permission to create branches
in someone else’s repository
or even if you do... it could get messy
mary’s refactor
master
mary’s fix
john’s feature
john’s test
a fork is your copy of a repo
your fork clean “upstream”
master fix2
fix1
origin/fix2
origin/master
master
just one more pointer to keep in mind
$ git fetch upstream master
fix
origin/fix
upstream/master
you can submit a pull request straight from your fork
fork (local)
upstream
fork (origin)
pull request
merge
push branch
TOOLS& RESOURCES
http://pragprog.com/book/tsgit/pragmatic-version-control-using-git
http://git-scm.com/book/
https://www.atlassian.com/git/tutorial/git-basics
http://try.github.io/
The end.