Git

On-line Book
- git config
  - --system, /etc/gitconfig, contains values for every user on the system and all their repositories
  - --global, ~/.gitconfig, specific to your user
  - --local, .git/gitconfig, specific to a project
  - -l, list all values
    - git config -l --show-list, list all values and locations
    - git config --global -l, list the global values
  - set a value
    - git config --global user.age 31
  - add a value
    - git config --global --add user.email lchen@ecsu.edu
  - remove values
    - git config --global --unset-all user.email
- git help
  - git help config, get the help information of "config"
- git init
  - Create a local repository
    - git init, initialize a local git repository
  - Create a repository shared by a group
    - mkdir rep.git, create a git folder
    - chgrp -R groupName rep.git
    - chmod 770 rep.git, make the folder readable and writable for user and group
    - chmod g+s rep.git, turn on setuid bit, user executing the file gets the permission of the group that owns the file
    - cd rep.git, enter the created folder
    - git init --bare --shared=660, or git init --bare --shre=group
  - git init --bare, create an empty git repository
    - mv hooks/post-update.sample to hooks/post-update
    - Git Hooks
- git clone
  - git clone [url], clone a repository to the current directory
  - git clone [url] [name], clone a repository to a target directory
  - fetch all remote branch, but only create one local branch master
  - git branch -a, display all branches
  - git checkout b_1, synchronize the branch from the remote
- git status
  - git status -s, show the modification status
    - '', unmodified
    - M, modified
    - A, added
    - D, deleted
    - R, renamed
    - C, copied
    - U, updated by unmerged
    - ??, untracked files
- git add
  - git add [fileName], add file contents to the index
    - index is a snapshot that is taken as the contents of the next commit
    - must use the add command to add any new or modified files to the index
  - git add *, add all files not in the gitignore list by default
  - git add [directory], stage all changes in [directory] for the next commit
  - git add -A, adds, modifies, and removes index entries to match the working tree
- .gitignore
  - gitignore template, usually .gitignore should be added into repository
  - gitignore tutorial
- git diff
  - git diff, the changes that have not yet been staged
  - git diff --staged/cached, changes staged that will go into your next commit
  - git diff --raw, generate the difference in the raw format
  - git diff --stat, generate a difference statement
  - git diff --summary, a summary for creation, renames and mode changes
  - git diff HEAD, changes in the working tree since the last commit
  - git diff b_1, compare with branch b_1
  - git diff HEAD -- fileName, changes in the fileName in the working tree since the last commit
  - git diff HEAD^ HEAD, compare the current version and its parent version
  - git diff b_1 master, compare two branches
  - git diff --diff-filter=MRC, show only modification, rename, and copy
  - git diff [commit_1] [commit_2], show the difference between two commits
- git commit, stores the current contents of the index in a new commit along with a log message
  - git commit -am, add the unstaged files to the current index, set a comment message, and store the contents
  - git add fileName, add the unstaged files to the current index
  - git rm fileName, remove files from the working tree and the index
    - Equals to "rm fileName", then "git add fileName"
  - git commit fileName, only commit the specific file
  - git commit --amend, append some updated to the previous commit
  - access commit
    - HEAD, refs
    - [commit], SHA1 checksum, or only the first a couple of characters of the SHA1 checksum
- git rm
  - git rm [fileName], remove a file and add it to index, equals to "rm", then "git add fileName"
  - if a file has been modified and added to the index, need -f to remove it to prevent the accidental removal of data that has not been recorded
  - git rm --cached [fileName], untrack a file, not in the index, but still in the work tree
- git mv, rename a file and add the information to the index
  - mv fromFile toFile
    - copy fileFile to toFile, toFile is an untracked file
    - remove fileFile
  - equals to "mv fromFile toFile", then "git rm fromFile", "git add toFile"
- git log/version/tag, show the commit logs of the current branch
  - git log -n 10, limit the number of commits to output
  - git log -p -2, show the difference between commits
  - git log --since "1 day ago", list all commits since one day ago
  - --after, --until, before
  - git log --author "Lin Chen", list all commits whose author is "Lin Chen"
  - git log -i --grep "t_4.*", list all commits whose messages contain "t_4" and ignore the case
  - git log --merges/--no-merges, list/not list all merge commits
  - git log --branches="b_1*", list all commits of the branches whose names contain "b_1"
  - git log --remotes="rep", list all commits of the remote repsitory "rep"
  - git log --reverse, list commits in reverse order
  - git rev-list --left-right --pretty=oneline [branchName], list a summary of the commits
  - git log --graph, draw a text-based graph of the commit history
  - git log --graph --all, draw a graph of the commit history for all branches
    - git log --graph --all --pretty=oneline
    - git log --graph --all --oneline --decorate
  - git log --name-status, show only names and status of changed files
  - git log --follow [fileName], show commits changed a specific file
  - git log [branchName], list commits of a specific branch
  - git log -p, list commits with patches
  - git log --stat, list commits with difference statement
  - git log -S "str", list commits that introduced a change to the code that added or removed that string
- gitk
  - gitk --all, show all branches
- git reset
  - Different between --soft, --mixed, and --hard
    - --soft, reset to a commit, but keep the current staged index
    - --mixed, default, reset to a commit and change the index, but not change work tree
    - --hard, reset to a commit, change both the index and the work tree
  - git reset HEAD -- [fileName], reset a staged file
  - git reset, reset to the last commit and remove the added file from tracking list
  - Change the commit message
    - git reset --soft HEAD^
    - git commit -a -c ORIG_HEAD
  - Rewind to a commit
    - git reset --hard HEAD~2, get rid of two commits
  - Rewind a pull
    - git pull
    - git reset --merge ORIG_HEAD
    - ORIG_HEAD, the last value of HEAD before dangeous operations
    - HEAD@{1}, the last value of HEAD
- git remote
  - remote -v, display the remote repositories
  - remote add [name] [url], add a remote repository
  - remote rename [old] [new], rename a remote repository
  - remote rm [name], remove a remote repository
  - remote set-ul [name] [url], set the url for a remote repository
  - remote show [name], display all branch information of the remote repository
- git fetch, fetch the data from the remote repository, but not merge to the current work tree
  - git fetch [repName], fetch the data from the remote repository
    - create several branch starting with "origin"
    - git checkout origin/master, enter into a detached branch and inspect files, if all satisfy the requirements, merge it to the work tree
  - git merge origin/master, merge a remote branch to the current branch
  - git fetch [repName] [branchName], fetch a specific branch from the remote repository
- git push
  - git push origin master, push the local master branch to the remote master branch
  - git push origin b_1, push the local branch b_1 to the remote branch b_1
  - git push origin master:b_1, push the local master branch to the remote branch b_1
  - git push origin HEAD:master, push the current branch to the remote master branch
  - git push origin --delete [branch], remove the branch in the remote repository
- git tag, create a tag for a commit
  - git tag, list all tags
  - git tag -a v1.0 -m message, create an anotate tag
  - git tag v1.0, create a lightweight tag
  - git tag -a v1.2 [commit], create a anotated tag for a specific commit
  - git show [tagName], show the information of a commit including the tag information
  - git rev-list -n 1 [tagName], show the commit that a tag pointing to
  - git describe [commit], show the tag name of a specific commit
  - git tag -d [tagName], delete a tag name
  - share tags
    - git push does not push tags to the remote repository
    - git push origin [tagName], push a tag to the remote repository
    - git push origin --tag, push all tags to the remote repository
- git pull
  - equals to "fetch", then "merge FETCH_HEAD"
  - git pull [remoteRepName] [remoteBranchName], fetch and merge a branch in the remote repository into the current branch
- git merge
  - Commit before merge
  - if no conflict, merge create a new commit
  - if has conflicts, merge does not create a new commit, the user need to fix the conflicts, then create a commit
    - git diff --name-only --diff-filter=U, list all unmerged files
  - git pull and git merge will stop without doing anything when local uncommitted changes overlap with files that git pull/git merge may need to update
  - git merg B1, merge B1 to the current branch, B1 is not deleted
  - git log --graph, show the branch and merge history
  - git merge orgin/master, merge the remote version to the current branch
  - Conflict
    - git status, check the conflict
    - Both changed the same part of the same file
    - One delete a file, one edit the same file
- git rebase
  - git rebase [base], rebase the current branch to the base branch
  - git rebase [base] [topic_branch], rebase the topic branch to the base branch
  - git rebase --onto [newbase] [oldbase] [topic_branch]
  - Never rebase commits once they've been pushed to a public repository
  - Steps
    1. git rebase [base]
    2. Manually resolve the conflicts
    3. git add *, mark the files as resolved
    4. git rebase --continue, so far, the current branch has been rebased to the base branch
    5. git checkout master, switch to master
    6. git merge b1, make the master and b1 point to the same commit
    7. git branch -d b1, remove the branch b1
- git branch
  - git branch, list the available branches
  - git branch -a, display all branches
  - git branch -v, display branches and the commit in each branch
  - git branch -r, list all remote branches
  - git branch -m, rename a branch
  - git branch -d, delete a branch
  - git branch -r -d origin/b_1, delete a branch on the remote repository
- git show, show one or more objects
  - git show, show the current HEAD
  - git show v1.0, display a tag
  - git show HEAD^{tree}, display the work tree
  - git show [branchName]^{tree}, display the work tree of a branch
  - git show [commit]^{tree}, display the work tree of a commit
  - git show v1.0^{commit}, display the commit of a tag
  - git show [branchName]:[fileName], display the content of a file in the specific branch
  - git show [commit]:[fileName], show the content of a file of a specific commit
- git checkout
  - commit before switching to another branch.
  - git checkout -- [fileName], restore a file from the index, back to the last staged version
    - --, avoid there is a branch having the same name as the file name
  - git checkout HEAD -- [fileName], restore a file from the last commit
  - git checkout [branch] -- [fileName], restore a file from a specific branch
  - git checkout [remoteBranch] -- [fileName], restore a file from a remote branch
  - git checkout -f, throw any local changes
    - git reset --hard HEAD, has the same effect
  - git checkoout b_1, switch to branch b_1
  - git checkout -b b_1, create branch b_1 and switch to branch b_1
  - git checkout -b [branch] [remote/branch], convert the detached branch to a local branch
    - git checkout --track [remote/branch]
  - git checkout [commit], switch to a commit
  - git checkout HEAD^
    - switch back to the parent commit
    - in a "detached HEAD" state, it a special branch, any commits in this state does not impact other branches, switching to another commit will drop it
    - git checkout -b [branchName], change the branch to a regular branch
  - git ls-files -d | xargs git checkout --, to restore all those deleted files in a folder
- git alias
  - git config --global alias.st status
    - git st, check the status
    - saved in ~/.gitconfig
- .gitconfig
  - gitconfig template
- git cat-file
  - git cat-file -p [commit]:[fileName], show the cotent of an object
- git archive
  - Create an archive of files from a named tree
  - git archive --format=tar --prefix=junk/ HEAD -o output.tar, create a tar archive that contains the contents of the latest commit on the current branch
- git grep
  - git grep keyword, search a keyword
  - git grep cout 1f1f8d, search the keyword in a commit
  - git grep cout v2.5, search the keyword in a tag
Git guys
- Glossary
- Data types in git
- blob
  - basic data storage unit
    - 100644 blob f283... f_1.txt
  - git hash-object [fileName], get the hash value of a file
  - git ls-tree HEAD, list all blobs of the current commit
- tree
  - refers other trees and blobs
- commits
  - refers to the main tree
- tag
  - give a name to a git commit
  - git cat-file -p v1.0, show the information of a tag
- index
  - Deal with the git index
  - contain the file list of staged files
  - git ls-files --stage, show the content of the index
  - [fileName] and [hashValue]
Documentation

Reference