From 05e9d5acd50071655900bd02d0b70b8f0cd70f02 Mon Sep 17 00:00:00 2001
From: sunface <cto@188.com>
Date: Wed, 23 Feb 2022 11:52:44 +0800
Subject: [PATCH] update cargo config

---
 contents/cargo/reference/configuration.md | 29 ++++++++++++++++-------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/contents/cargo/reference/configuration.md b/contents/cargo/reference/configuration.md
index 73343f72..5b96cfc8 100644
--- a/contents/cargo/reference/configuration.md
+++ b/contents/cargo/reference/configuration.md
@@ -105,18 +105,18 @@ rpath = false
 [profile.<name>.build-override]  
 [profile.<name>.package.<name>]  
 
-[registries.<name>]  # registries other than crates.io
-index = "…"          # URL of the registry index
-token = "…"          # authentication token for the registry
+[registries.<name>]  # 设置其它的注册服务： https://course.rs/cargo/reference/specify-deps.html#从其它注册服务引入依赖包
+index = "…"          # 注册服务索引列表的 URL 
+token = "…"          # 连接注册服务所需的鉴权 token
 
 [registry]
-default = "…"        # name of the default registry
-token = "…"          # authentication token for crates.io
+default = "…"        # 默认的注册服务名称: crates.io
+token = "…"             
 
-[source.<name>]      # source definition and replacement
-replace-with = "…"   # replace this source with the given named source
+[source.<name>]      # 注册服务源和替换source definition and replacement
+replace-with = "…"   # 使用给定的 source 来替换当前的 source，例如使用科大源来替换crates.io源以提升国内的下载速度：[source.crates-io] replace-with = 'ustc'
 directory = "…"      # path to a directory source
-registry = "…"       # URL to a registry source
+registry = "…"       # 注册源的 URL ，例如科大源: [source.ustc] registry = "git://mirrors.ustc.edu.cn/crates.io-index"
 local-registry = "…" # path to a local registry source
 git = "…"            # URL of a git repository source
 branch = "…"         # branch name for the git repository
@@ -147,4 +147,15 @@ verbose = false        # whether cargo provides verbose output
 color = 'auto'         # whether cargo colorizes output
 progress.when = 'auto' # whether cargo shows progress bar
 progress.width = 80    # width of progress bar
-```
\ No newline at end of file
+```
+
+## 环境变量
+除了 `config.toml` 配置文件，我们还可以使用环境变量的方式对 Cargo 进行配置。
+
+配置文件的中的 key `foo.bar` 对应的环境变量形式为 `CARGO_FOO_BAR`，其中的`.`、`-` 被转换成 `_`，且字母都变成大写的。例如，`target.x86_64-unknown-linux-gnu.runner` key 转换成环境变量后变成 `CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER`。
+
+就优先级而言，环境变量是比配置文件更高的。除了上面的机制，Cargo 还支持一些[预定义的环境变量](https://doc.rust-lang.org/stable/cargo/reference/environment-variables.html)。
+
+
+> 官方 Cargo Book 中本文的内容还有[很多](https://doc.rust-lang.org/stable/cargo/reference/config.html#configuration-keys)，但是剩余内容对于绝大多数用户都用不到，因此我们并没有涵盖其中。
+