gitpro 阅读笔记

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Gitpro

git 对象模型

Git 并不是单纯的版本控制器，本质上它是一个 内容寻址文件系统（content-addressable filesystem）。

  • 每个对象（blob、tree、commit、tag）都通过其内容计算哈希（SHA-1 或 SHA-256）作为键存储在 .git/objects/ 中。
  • 这种方式使得对象的唯一性和完整性由哈希保证。
  • 逻辑上，Git 的提交是快照，但快照的存储完全依赖对象的引用关系。

Git 对象模型

Git 的对象（object）类型主要有四种：

  1. Blob 对象（binary large object）

    • 存储文件内容。
    • 内容完全相同的文件 → 哈希相同 → 对象复用。
    • 不存文件名，文件名存在于 tree 对象。

  2. Tree 对象

    • 存储目录结构。
    • 包含若干条目，每个条目包含：权限、文件名、指向 blob 或子 tree 的哈希。
    • 即一个有向无环图（DAG）结构，而不是简单的复制。

  3. Commit 对象

    • 存储元数据：

      • 指向根 tree 的指针
      • 父提交的指针（可多个 → 支持分支/合并）
      • 作者、提交者、提交信息

    • commit 是对某个 tree 快照的引用。

  4. Tag 对象

    • 可选，对 commit、tree 或 blob 进行命名。

git config

  1. /etc/gitconfig applied to every user. pass the option --system
  2. ~/.gitconfig or ~/.config/git/config applied for the user. pass the option --global
  3. .git/config applied to the repositor. pass the option --local
  4. git config --list --show-origin show all settings and where they are
  5. git config user.name show the config of username
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git config --global alias.st status #aliase

set identity

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git config --global user.name "name"
git config --global user.email "email@mail.com"

set editor

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git config --global core.editor vim

set default branch name

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git config --global init.defaultBranch main

to set default branch as main rather than master

get help

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git help <verb>
git <verb> --help
man git-<verb>

some buildin command also can be ask git <verb> -h

git clone

to set an anther name of the repository by

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git clone URL newname

git add

to track file

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git add files

git stataus

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git status #to show the repository status, filse be tracked or staged
git status -s #--short

gitignore

the rules for the patterms:

  1. bland line or lines starting with # are ignored
  2. lines start with slash/ will avoid recursivity
  3. lines end with slash/ to specify a directory
  4. lines start with point! to be negated a pattern
  5. standard glob patterns works

    * to matches zero to more characters;
    [abs\] to matches characters inside the brackets
    ? to matches a single charater
    ** to matches nested directories
    [0-9] to matches any character between them

git diff

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git diff # to show the difference between changed but not yet staged files
git diff --staged #--cached to show the difference between staged and the last commited

git commit

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git commit # to commit the staging area
git commit -m "message" #
git commit -a # to skip the staging area
git commit --amend #to commit the staging area files to the latstest commit or rewrite commit message

git rm

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git rm filse # to remove the staged filse from staging area and working directory
git rm -f filse # to remove tracked but not yet added filse
git rm --cached # to remove filse only from staging area but not delete from working directory

git mv

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git mv fromfile tofile # to move filse or remane file
# equl to the following command
mv fromfile tofile
git rm fromfile
git add tofile

git log

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git log # to show all commits information , auther, time, sorted by time
git log -p -2 #--patch to show the difference introduced in each commit, limit the number of commit
git log --stat #to show abbreviated stats
git log --pretty=oneline #also short, full, fuller, to show the output in specifical format
git log --pretty=format"%n - %an, %ar : %s" #to format output
git log --graph #to add a nice ASCII graph showing your branch and merge historyg

git log --since=2.weeks
git log --until=2.weeks
git log -S string #to show some commits that add/remove the paticular string
#there are also some option that I cant record, I can refer in [gitpro](https://git-scm.com/book/zh/v2/Git-%E5%9F%BA%E7%A1%80-%E6%9F%A5%E7%9C%8B%E6%8F%90%E4%BA%A4%E5%8E%86%E5%8F%B2)

git log --decorate #show each branch point which object
git log --oneline --decorate --graph --all #output the commit history, branch pointer and diverged

git reset

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git reset HEAD <file> # to reset file to the lastest commited version, in anther way , to clear the file from staging area
git reset --soft <commit> # to redo the lastest commit but keep the modified
git reset --hard <commit> # to back to the commit status in staging area and work directory, and do not keey the modified

git checkout

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git checkout -- <file> # to discard changes in wording diretory
git checkout 2.2.0 # check out tags
git checkout <branch> #check out the branch
git switch <branch>
git checkout -b <newbranchname> #create and checkout the branch

git restore

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git restore --staged <file> # to unstage the file but not discard modification
git restore <file> # to dicard the modification of the file

git remote

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git remote # to show the remote servers name, origin
git remote -v # to show the URLs that your can pull and fetch
git remote add <shortname> <url> # to add a remote repository and give it a shortname
git remote show <remote> # to show detailed imformation of the remote
git remote rename oldname nowname # to rename the remote
git remote remove <remote> # to remove the remote repository

git fetch

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git fetch <remote> # fetch remote repository by URL or shortname, and the default name of cloned repository is origin

git push

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git push origin master # to push master branch to upstream(remote)
git push origin v1.5 # push tag to remote
git push origin --tag # push all tags to remote
git push origin :refs/tags/v1.4 #push null value before the colon: to the remote 
git push origin --delete <tagname> # delete the tag

git tag

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git tag # to list existing tags
git tag -l "v1.8*" #--list to list particular tags
git tag v1.0.0 -lw # a lightweight tag, just a pointer
git tag -a v1.0.0 -m "First stable release" #Annotated tag, attach other information
git show v1.0.0 # to show the imformation of the tag and commit
git tag -a v1.2 9fceb02 # to add a tag to a commit
git tag -d <tagname> # to delete a lightwight tag

branch

they are three object
each commit object contain there parent

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git branch #list all branch 
git branch newbranchname #create a new branch
git branch -d <branch> #delete the branch
git branch --merged #filter the merged branch, and --no-merged

git merge

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git merge <bemergedbranch> #to merge a branch

if there is any conflict in the merge, you can check by running git status, and then modify the file . after that, run git add on each file to mark it as resolved