概述
git diff命令用于查看文件之间的差异。
命令
工作区与暂存区
查看工作区与暂存区的差异
git diff
查看工作区与暂存区某个文件的差异
git diff [file]
git diff file.txt
// 或
git diff -- [file]
git diff -- ./[file]
查看工作区与暂存区多个文件的差异，以空格分隔
git diff -- [file1] [file2]
查看工作区与暂存区目录下所有文件的差异
git diff -- [dir]/
工作区与commit快照
查看工作区与上一次commit之间的差异
git diff HEAD
查看工作区与某个 commit 的差异
git diff [commit]
当我们修改工作区的内容后，我们没有暂存，也没有提交，所以此时暂存区和仓库的状态是相同的。
即此时git diff 与git diff HEAD返回的结果是完全相同的
当我们执行git add命令后，此时git diff不会显示任何内容，因为此时工作区与暂存区没有差异。
但是如果执行git diff HEAD命令，仍然可以查看到工作区和提交之间的差异。
假如此时再次修改工作区的内容，我们就能同时对比工作区和(暂存区/仓库)的差异
并且此时暂存区和仓库也是有差异的
暂存区与仓库区
查看暂存区与当前 commit 的差异
git diff --cached
对比两次提交
显示两次提交之间的差异
git diff [first-commit] [second-commit]
我们也可以使用引用，更加方便的对比，比如：最新提交和上一次提交
git diff HEAD HEAD~
对比两个分支
即对比两个分支上最新提交之间的差异
git diff [first-branch] [second-branch]
git diff master dev
// 等效于
git diff [first-branch]..[second-branch]
git diff maste..dev
查看自从topic分支建立以后，master分支发生的变化
git diff topic...master
总结
查看工作区与暂存区的差异
git diff
查看工作区与上一次commit之间的差异
git diff HEAD
查看暂存区与当前 commit 的差异
git diff --cached