git and github is totally different thing.
The main architecture used in github is git.
git is one of the version control system,
created by Linus Torvalds (also the founder of Linux).
In this document, git architecture and git usage is
simply explaind.
Before starting git, it is good for you to add the code below to your ~/.bash_profile
Basic bash setting.
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
export GIT_EDITOR=vim
export LC_ALL=en_US.UTF-8
export LC_ALL=ja_JP.UTF-8
Git branch in prompt (useful)
parse_git_branch() {
git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* (.*)/ (\1)/'
}
export PS1="\u \W[\033[32m]$(parse_git_branch)[\033[00m] $ "
Be careful, this is different from github initial setting.
git init creates .git directory, and initialize git.
git init
git add .
git commit
See the history of commits.
git log
See the detail record of a commit.
git show <SHA1 hash>
See the simple record of commits according to each branch.
git show-branch --more=10
-
blob
Stands for binary large object.
Git does not use file name, but use SHA1 hash generated
with binary code of each file. -
tree
Express one directory information. -
commit
Metadata for each change to a repository. -
tag
Alias for commit.
-
tracked.
Files which are already in repository, or are indexed. -
ignored.
Files which explicitly declared as ignore. -
untracked.
Files belonging to neither of tracked or ignored.
Example case.
(start with clean status, which means all files are tracked or ignored.)
This example creates tracked, ignored and untracked file.
(and if you already have .gitignore file, you can also see changes files,
which are also one of the untracked files. )
echo "dirty file" > dirty1.txt
echo "dirty file" > dirty2.txt
echo " dirty file" > dirty3.txt
echo dirty3.txt > .gitignore
git add dirty1.txt
git status
- Note.
If .gitignore is not sharing with other branches,
This makes problem if you checkout another branch.
That file remains and in another branch, treated as a untracked file.
See the picture below.
git add . adds only files under a current directory.
-
reference (ref)
SHA1 hash ID pointing at the object within a object strage. -
symbolic reference (symref)
Indirect reference name.
-
HEAD
Symref for the newest commit in the current branch. -
ORIG_HEAD
Previous HEAD. -
FETCH_HEAD
If you fetch a remote repository, the head commit of the branch is
registered in the FETCH_HEAD -
MERGE_HEAD
A commit that will be merged to HEAD.
Examples.
-
master^ = master~
The second newest commit in the master branch. -
master~2
The third newest commit in the master branch.
Useful options.
git log --pretty[=oneline|short|full] --abbrev-commit --stat`
pretty means amount of output.
abbrev means abbreviation of commit ID.
stat means list edited files and summarize edited lines for each file.
Examples.
git log HEAD~10.. --pretty=oneline --abbrev-commit
(same as git log HEAD~10..HEAD --pretty=oneline --abbrev-commit)
git log HEAD~2.. --stat
cf.
git show HEAD~2..
git log -1 -p HEAD~3
(same as git log -1 -p master HEAD^3
-p means difference, and -1 is # of output.
-
gitk
The graph exists in the left top of the window. -
git log with simple options
git log --graph --pretty=oneline --abbrev-commit
- git log with complicated options
git log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all
or
git log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n'' %C(white)%s%C(reset) %C(dim white)- %an%C(reset)' --all
from this post. https://stackoverflow.com/questions/1057564/pretty-git-branch-graphs
etc...
-gitg
-GitGraph.js (https://qiita.com/uzuki\_aoba/items/76e59f65cb50ef020e3c)
-gitdags
-
git diff
Show difference between working directory and index.
It means telling me differences to be indexed. -
git diff _commit_
Show difference between working directory and commit.
Frequent usage may begit diff HEAD. -
git diff --cached _commit_
Show difference between index and commit.
Frequent usage may begit diff --cached HEADorgit diff --cached.
git's main troublesome things will be "merge". Then, this chapter, we will explore how to solve conflicts elegantly.
git init
echo "hello world" > text.txt
git add .
git commit
git branch test
echo "dirty line" >> text.txt
git add .
git commit
git checkout test
echo "hello2 world" >> text.txt
git add .
git commit
git merge master
git status or git ls-files -u is good.
Also if you want to find out differences between files,
git diff
git diff MERGE\_HEAD
git diff --stat
are options.
If you want to find out commits that cause the conflicts, use the code below.
git log --merge --left-right -p
git log --merge --left-right -p <filename>
Q. if you want to adopt whole changes of one branch, how?
A.
If you want to adopt branch which you are now checking out, use --ours,
els use --theirs.
This code is for each file.
git checkout --[ours|theirs] <filename>
This code should be used after reset merge,
git merge -X[ours|theirs] <branchname>
Q. if you want to cancel merge, how?
A.
git reset --hard HEAD
After you merge, and want to reset merge,
git reset --hard ORIG_HEAD
Be careful, if you start merge in the dirty directory, your untracked files are lost completely.
git cherry-pick is recommit to the branch.
git revert is reverse commit to the branch. git revert can be used for cancel the commit.
If you share work in remote repository, it is simplest (maybe not best) wasy to update your working.
git pull origin master
__edit_files__
git add .
git commit -m "some comment"
git push origin master
You clone origin repository at the time of B.
You write some program and commit twice ( X and Y ).
Also, origin repository is edited by some other person ( C and D).
How you can update your change into origin repository?
git fetch (the first process of git pull) allows you
to fetch repository history from origin,
and save this into origin/master branch.
Then, the answer is,
git fetch origin master
git merge origin/master
or
git pull origin master
and after your resolve conflicts ( if exists),
type the code below.
git push origin master
Then you can update origin repository.
This is one example of usage of github.
- Anything in the master branch is deployable
- To work on something new, create a descriptively named branch off of master (ie: new-oauth2-scopes)
- Commit to that branch locally and regularly push your work to the same named branch on the server
- When you need feedback or help, or you think the branch is ready for merging, open a pull request
- After someone else has reviewed and signed off on the feature, you can merge it into master
- Once it is merged and pushed to ‘master’, you can and should deploy immediately
See the detail, https://gist.github.com/Gab-km/3705015
This picture is one good management style, cited from
A successful Git branching model.
A part of this document is old, but many are still useful.
Q. How to make new branch from old commit?
A.
git checkout <SHA1 hash>
The branch is changed to detached HEAD.
git branch <branchname>
git checkout <branchname>
Then, you can work from the specific commit status.