前置知识: Git

git-diff与暂存区操作

2 minIntermediate2026/6/14

git diff与diff --staged的详细用法：差异比较、输出格式与实用技巧。

1. git diff 概述

1.1 diff 的三种模式

命令比较对象用途
git diff工作区 vs 暂存区查看未暂存的修改
git diff --staged暂存区 vs 最新提交查看已暂存的修改
git diff <commit>工作区 vs 指定提交查看与指定提交的差异

2. diff 输出格式

2.1 标准输出

diff --git a/src/index.js b/src/index.js
index abc1234..def5678 100644
--- a/src/index.js
+++ b/src/index.js
@@ -10,7 +10,8 @@ function process(data) {
   const result = transform(data);
   if (result.isValid) {
-    return result.value;
+    const processed = enhance(result.value);
+    return processed;
   }
   return null;
 }

2.2 输出解读

部分含义
diff --git a/... b/...比较的文件路径
index abc1234..def5678对象哈希范围
100644文件模式
--- a/src/index.js原文件
+++ b/src/index.js新文件
@@ -10,7 +10,8 @@变更位置（旧文件第10行起7行，新文件第10行起8行）
- 前缀删除的行
+ 前缀新增的行
空格前缀上下文行

2.3 统计输出

git diff --stat
#  src/index.js    | 3 ++-
#  src/utils.js    | 5 +++--
#  2 files changed, 4 insertions(+), 4 deletions(-)

git diff --numstat
# 2       1       src/index.js
# 3       2       src/utils.js
# ↑新增行  ↑删除行

3. 常用 diff 选项

3.1 过滤选项

# 只看文件名
git diff --name-only

# 只看文件名和状态
git diff --name-status
# M  src/index.js      ← Modified
# A  src/new.js        ← Added
# D  src/old.js        ← Deleted

# 按路径过滤
git diff -- src/
git diff -- '*.js'
git diff -- ':(exclude)*.test.js'

3.2 显示选项

# 增加上下文行数
git diff -U5              # 5行上下文（默认3行）

# 忽略空白
git diff -w               # 忽略所有空白变化
git diff --ignore-space-at-eol  # 只忽略行尾空白

# 彩色输出
git diff --color-words    # 词语级别的差异高亮
git diff --word-diff      # 词语级别的差异标记

# 函数上下文
git diff -W               # 显示完整函数

3.3 比较选项

# 比较两个分支
git diff main..feature

# 比较两个提交
git diff abc1234..def5678

# 比较分支分叉点以来的变化
git diff main...feature   # feature 相对于 main 的变更

# 只看暂存区与 HEAD 的差异
git diff --staged
git diff --cached         # 同上

4. 高级用法

4.1 比较特定文件

# 比较特定文件在不同提交间的差异
git diff HEAD~3 -- src/index.js

# 比较两个分支的特定文件
git diff main feature -- package.json

4.2 交互式 diff

# 逐文件查看 diff
git diff --stat | fzf | xargs -I{} git diff -- {}

# 使用 difftool
git difftool              # 使用配置的 diff 工具
git difftool --tool=vimdiff

4.3 查看合并冲突的差异

# 查看冲突标记
git diff --check          # 标记空白错误和冲突标记

# 合并冲突的三方差异
git diff HEAD...MERGE_HEAD

5. diff 算法

5.1 算法选择

# 默认算法（Myers diff）
git diff

# 耐心算法（更好的人类可读性）
git diff --patience

# 直方图算法
git diff --histogram
算法特点适用场景
Myers默认，快速通用
Patience关注唯一行匹配代码重构
HistogramPatience 的改进复杂变更

5.2 重命名检测

# 检测文件重命名
git diff -M               # 检测重命名（默认50%相似度）
git diff -M50%             # 50%相似度阈值
git diff -M90%             # 90%相似度阈值（更严格）

# 检测文件复制
git diff -C               # 检测复制
git diff -C -M             # 同时检测重命名和复制

6. 实用别名

# .gitconfig
[alias]
    d = diff
    ds = diff --staged
    dn = diff --name-only
    dns = diff --staged --name-only
    dw = diff --color-words
    dws = diff --staged --color-words
    dst = diff --stat
    dsts = diff --staged --stat