【Git】git commit_git commit -amend

参考源站了解更多: Git讲之git commit

git commit命令将Staging阶段的代码提交至History状态.

我们以上面的文件为例，进行commit提交:

$ git commit -m "add README.txt"
[master (root-commit) be57548] add README.txt
 1 file changed, 1 insertion(+)
 create mode 100644 README.txt

$ git log
commit be57548a25efd89b6e686b622188ad2135cb246b (HEAD -> master)
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 16:12:39 2020 +0800

    add README.txt

$ git cat-file -t be57548a25efd89b6e686b622188ad2135cb246b #commit操作后，得到一个commit类型对象
commit

$ git cat-file -p be57548a25efd89b6e686b622188ad2135cb246b
tree 3ff7ec4f18fa77a0277bd1397b3248c49d9c5ba4  #commit类型的对象包含一个tree类型的对象
author jiangjian <jiangjian199204@gmail.com> 1608106359 +0800
committer jiangjian <jiangjian199204@gmail.com> 1608106359 +0800

add README.txt

$ git cat-file -t 3ff7ec4f18fa77a0277bd1397b3248c49d9c5ba4
tree

$ git cat-file -p 3ff7ec4f18fa77a0277bd1397b3248c49d9c5ba4 #tree类型的对象里面记录着tree对象的子节点
100644 blob 5da849b5c6f00b5292b1a823b29ceb303e98585c    README.txt
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上面的操作过程中，我们得到一个commit类型的对象，通过该对象内部包含的tree类型对象，我们可以将当前commit指向的tree对象的所有子节点遍历，就可以得到当前commit状态的整个文件状态,我们可以将上面的3个类型对象进行关联起来.

我们再继续添加一个commit来了解一下commit之间如何关系的, 一顿操作如下:

$ echo "print 'hello world'" > 1.py #新增一个1.py的文件

$ git add 1.py #将1.py文件加到Staging 区域
warning: LF will be replaced by CRLF in 1.py.
The file will have its original line endings in your working directory

$ git commit -m "add 1.py file" # 将1.py文件从Staging 区域转移到History区域
[master 3ca8f94] add 1.py file
 1 file changed, 1 insertion(+)
 create mode 100644 1.py

$ git log # 查看git commit记录,可以看到有两个commit log记录，默认排序按时间倒序
commit 3ca8f948d5d93569fd87806cf71bddf93d1bb00c (HEAD -> master) 
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 16:53:19 2020 +0800

    add 1.py file

commit be57548a25efd89b6e686b622188ad2135cb246b
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 16:12:39 2020 +0800

    add README.txt

$ git cat-file -p 3ca8f948d5d93569fd87806cf71bddf93d1bb00c # 我们查看最近提交的commit对象内容
tree af324ffc63f85247ee61e8538fced865915fddce # commit
parent be57548a25efd89b6e686b622188ad2135cb246b # commit对象存在父子关系，当前的commit父节点是上一次提交commit的id
author jiangjian <jiangjian199204@gmail.com> 1608108799 +0800
committer jiangjian <jiangjian199204@gmail.com> 1608108799 +0800

add 1.py file

$ git cat-file -p af324ffc63f85247ee61e8538fced865915fddce # 我们查看最近提交commit中tree对象的内容，可以了解到里面有两个blob,因为我们连续添加了两个文件,所以通过遍历该tree的子节点和内容可以将commit提交时的整个工程状态进行还原
100644 blob a968078c845da96a55c4ba1b21c38cdef55ddf2a    1.py
100644 blob 5da849b5c6f00b5292b1a823b29ceb303e98585c    README.txt
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我们通过如下的图可以了解到整个的关系:

接下来，我们看一下添加目录会涉及到什么新事物:

$ mkdir log # 创建log目录

$ echo "1" > log/1.log
$ git add .
warning: LF will be replaced by CRLF in log/1.log.
The file will have its original line endings in your working directory

$ git commit -m "add log file"
[master 5ede504] add log file
 1 file changed, 1 insertion(+)
 create mode 100644 log/1.log

$ git log
commit 5ede5043e4d3037c691f3344a2dfda4ec82b869a (HEAD -> master)
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 17:31:44 2020 +0800

    add log file

commit 3ca8f948d5d93569fd87806cf71bddf93d1bb00c
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 16:53:19 2020 +0800

    add 1.py file

commit be57548a25efd89b6e686b622188ad2135cb246b
Author: jiangjian <jiangjian199204@gmail.com>
Date:   Wed Dec 16 16:12:39 2020 +0800

    add README.txt

$ git cat-file -p 5ede5043e4d3037c691f3344a2dfda4ec82b869a
tree 5340eab424a090849b51164cbc8dc5c5396fe82b
parent 3ca8f948d5d93569fd87806cf71bddf93d1bb00c
author jiangjian <jiangjian199204@gmail.com> 1608111104 +0800
committer jiangjian <jiangjian199204@gmail.com> 1608111104 +0800

add log file

$ git cat-file -p 5340eab424a090849b51164cbc8dc5c5396fe82b
100644 blob a968078c845da96a55c4ba1b21c38cdef55ddf2a    1.py
100644 blob 5da849b5c6f00b5292b1a823b29ceb303e98585c    README.txt
040000 tree be2f1df0ca9f269f282a0baa9f247f8c03438a02    log

$ git cat-file -p be2f1df0ca9f269f282a0baa9f247f8c03438a02
100644 blob d00491fd7e5bb6fa28c517a0bb32b8b506539d4d    1.log

$ git cat-file -p d00491fd7e5bb6fa28c517a0bb32b8b506539d4d

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通过上面的图示可以了解到新建的目录都会新增一个tree类型节点用来代表该目录