git diff — Seeing What Changed

Comparing Versions

# What changed in working dir vs last commit (unstaged)?
git diff

# What's staged (ready to commit)?
git diff --staged

# Difference between two commits:
git diff abc123 def456

# Difference between two branches:
git diff main feature-branch

Reading a diff

-old line that was removed
+new line that was added
 unchanged context line

git show — inspect a specific commit

git show HEAD          # last commit
git show HEAD~1        # commit before last
git show abc1234       # specific commit by hash

HEAD — the current position

HEAD is a pointer to the commit you're currently working from — usually the tip of the branch you're on. HEAD~1 means "one commit before HEAD".

Your Task

A file has been committed. Modify it, then stage the change. The tests verify you have a staged diff ready to commit.