这才是真正的Git

$ git init
$ echo '111' > a.txt
$ echo '222' > b.txt
$ git add *.txt

$ tree .git/objects
.git/objects
├── 58
│   └── c9bdf9d017fcd178dc8c073cbfcbb7ff240d6c
├── c2
│   └── 00906efd24ec5e783bee7f23b5d7c941b0c12c
├── info
└── pack

$ cat .git/objects/58/c9bdf9d017fcd178dc8c073cbfcbb7ff240d6c
xKOR0a044K%

$ git cat-file -t 58c9
blob
$ git cat-file -p 58c9
111

$ git commit -m '[+] init'
$ tree .git/objects
.git/objects
├── 0c
│   └── 96bfc59d0f02317d002ebbf8318f46c7e47ab2
├── 4c
│   └── aaa1a9ae0b274fba9e3675f9ef071616e5b209
...

$ git cat-file -t 4caaa1
tree
$ git cat-file -p 4caaa1
100644 blob 58c9bdf9d017fcd178dc8c0...	a.txt
100644 blob c200906efd24ec5e783bee7...	b.txt

$ git cat-file -t 0c96bf
commit
$ git cat-file -p 0c96bf
tree 4caaa1a9ae0b274fba9e3675f9ef071616e5b209
author lzane 李泽帆  1573302343 +0800
committer lzane 李泽帆  1573302343 +0800
[+] init

$ cat .git/HEAD
ref: refs/heads/master

$ cat .git/refs/heads/master
0c96bfc59d0f02317d002ebbf8318f46c7e47ab2

• 工作目录 （ working directory ）：操作系统上的文件，所有代码开发编辑都在这上面完成。
• 索引（ index or staging area ）：一个暂存区域，会在下一次commit被提交到Git仓库。
• Git仓库（ git repository ）：由Git object记录着每一次提交的快照，以及链式结构记录的提交变更历史。

$ git reflog
e171c5f (HEAD -> article/git, origin/article/git) HEAD@{0}: commit: [+] writing
7788bcd HEAD@{1}: commit: [+] writing
adbb712 HEAD@{2}: commit: [*] 修改构建脚本
7341618 HEAD@{3}: commit: [+] writing
925c148 HEAD@{4}: pull: Fast-forward
6952e07 HEAD@{5}: commit: [+] writing
c92a024 HEAD@{6}: commit: [+] 添加文章内容
cfb234e (origin/master, origin/HEAD, master) HEAD@{7}: reset: moving to HEAD~2