Git & GitHub · Chapter 12 of 42
git diff
The `git diff` command shows the exact line-by-line differences between your working directory, staging area, and commits. It's essential for reviewing changes before committing.
By default, `git diff` shows unstaged changes. Adding `--staged` (or `--cached`) shows what's staged and ready to be committed instead.
Syntax
git diff
git diff --staged
git diff commit1 commit2Comparing working directory changes
Running `git diff` with no arguments shows differences between your working directory and the last commit for files that are not yet staged.
Comparing staged changes and commits
`git diff --staged` shows staged changes compared to the last commit. `git diff commit1 commit2` compares two specific commits.
Example 1 (bash)
git diff app.jsOutput
-const x = 1;
+const x = 2;Shows that the line 'const x = 1;' was changed to 'const x = 2;' in app.js.
Example 2 (bash)
git add app.js
git diff --stagedOutput
-const x = 1;
+const x = 2;After staging, --staged shows the same change is now ready to be committed.
Key points
- git diff shows line-by-line differences between file versions.
- By default it compares working directory to the last commit.
- --staged shows differences already added to the staging area.
- You can diff between any two commits by hash or branch name.
💡 Note: Lines starting with - are removed and lines starting with + are added in the diff output.