git - diff.mnemonicprefix 有什么作用？

Question

我注意到 SourceTree 使用此配置选项执行 git 命令:

git -c diff.mnemonicprefix=false 

这就是git docs说说这个选项:

diff.mnemonicprefix

If set, git diff uses a prefix pair that is different from the standard "a/" and "b/" depending on what is being compared. When this configuration is in effect, reverse diff output also swaps the order of the prefixes:

git diff compares the (i)ndex and the (w)ork tree;

git diff HEAD compares a (c)ommit and the (w)ork tree;

git diff --cached compares a (c)ommit and the (i)ndex;

git diff HEAD:file1 file2 compares an (o)bject and a (w)ork tree entity;

git diff --no-index a b compares two non-git things (1) and (2).

我还是不明白这是什么意思。谁能解释一下？

Answer 1

git diff 显示有关它正在比较的文件的一些元数据。通常你可能会看到这样的东西:

diff --git a/foo/bar.txt b/foo/bar.txt        <--
index abcd123..1234abc 100644
--- a/foo/bar.txt                             <--
+++ b/foo/bar.txt                             <--

请注意如何在我用箭头指示的三行上使用 a/ 和 b/ 来区分文件。这是非助记的；字符 a 和 b 没有实际意义。

启用 diff.mnemonicprefix 后，将按照您引用的文档中的描述选择这些字符。例如，如果您对本地副本进行了更改并且正在与索引进行比较(例如使用 git diff)，您会看到类似

的内容

diff --git i/foo/bar.txt w/foo/bar.txt
index abcd123..1234abc 100644
--- i/foo/bar.txt
+++ w/foo/bar.txt

相反。字符 i 和 w 分别用于指示您的索引和工作副本。

文档中列出的其他案例的工作方式类似。