git diff for working directory changes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the command git diff show by default?

It shows the changes in the working directory that are not yet staged for commit.

beginner

How can you see the changes that are staged for the next commit?

Use git diff --cached or git diff --staged to see staged changes.

intermediate

What is the difference between git diff and git diff HEAD?

git diff shows unstaged changes, while git diff HEAD shows all changes (staged and unstaged) compared to the last commit.

beginner

How do you limit git diff output to a specific file?

Add the file name at the end, like git diff filename.txt.

beginner

What does the output of git diff look like?

It shows lines removed with a minus (-) and lines added with a plus (+), highlighting the exact changes.

What does git diff show by default?

A All files in the repository

B Changes already committed

C Changes staged for commit

D Changes in the working directory not staged for commit

git diff by default shows changes in your working directory that you have not yet staged.

Which command shows changes staged for the next commit?

A git diff --cached

B git diff HEAD

C git status

D git log

git diff --cached shows the staged changes ready to be committed.

How do you see all changes (staged and unstaged) compared to the last commit?

A git diff

B git diff HEAD

C git diff --staged

D git show

git diff HEAD compares your current working directory and staging area to the last commit.

What symbol in git diff output indicates a line was removed?

A *

B +

C -

D #

Lines removed are shown with a minus (-) sign in git diff output.

How to limit git diff output to a single file?

A git diff filename

B git diff --file filename

C git diff --only filename

D git diff -f filename

Simply add the file name after git diff to see changes for that file only.

Explain what git diff shows and how it helps in tracking changes.

Think about what you see before you save your work.

Describe the difference between git diff and git diff --cached.

One shows changes not ready to commit, the other shows changes ready to commit.

Practice

1. What does the command git diff show you?

easy

A. The current branch name

B. The changes in your working directory that are not yet staged

C. The list of all commits in the repository

D. The status of remote branches

Solution

1. Step 1: Understand the purpose of git diff

   git diff compares your working directory files with the last saved snapshot (commit or staged changes).

2. Step 2: Identify what git diff outputs

   It shows the differences that are not yet staged for commit, meaning changes you made but haven't told git to save yet.

3. Final Answer:

   The changes in your working directory that are not yet staged -> Option B

4. Quick Check:

   git diff = unstaged changes [OK]

Hint: git diff shows unstaged file changes only [OK]

Common Mistakes:

• Confusing git diff with git status
• Thinking git diff shows committed changes
• Assuming git diff shows staged changes

2. Which of the following is the correct syntax to see changes only in a single file named app.js?

easy

A. git diff --single app.js

B. git diff --file app.js

C. git diff -f app.js

D. git diff app.js

Solution

1. Step 1: Recall the basic git diff syntax

   The command to check changes in a specific file is git diff <filename>.

2. Step 2: Match the correct option

   Only git diff app.js uses the correct syntax: git diff app.js. Other options use invalid flags.

3. Final Answer:

   git diff app.js -> Option D

4. Quick Check:

   git diff + filename = correct syntax [OK]

Hint: Use git diff followed by filename to check one file [OK]

Common Mistakes:

• Adding unsupported flags like --file or --single
• Using -f which is not for git diff
• Confusing git diff syntax with other git commands

3. Given the following scenario: You modified a file index.html by adding a new line. What will git diff index.html show?

medium

A. The difference showing the added line in index.html

B. An error saying file not found

C. No output because changes are staged

D. The full content of index.html

Solution

1. Step 1: Understand what git diff shows for a modified file

   When a file is changed but not staged, git diff filename shows the exact changes line by line.

2. Step 2: Apply this to index.html

   Since you added a line and did not stage it, the command will show the added line as a difference.

3. Final Answer:

   The difference showing the added line in index.html -> Option A

4. Quick Check:

   git diff filename = shows unstaged changes [OK]

Hint: git diff filename shows unstaged changes in that file [OK]

Common Mistakes:

• Expecting full file content instead of diff
• Thinking git diff shows staged changes
• Assuming error if file exists

4. You ran git diff but saw no output, even though you edited files. What could be the reason?

medium

A. You have untracked files only

B. You are on a detached HEAD state

C. You already staged the changes with git add

D. You have no git repository initialized

Solution

1. Step 1: Understand what git diff shows

   git diff shows changes in the working directory that are not staged.

2. Step 2: Analyze why no output appears despite edits

   If changes are already staged using git add, git diff will show nothing because working directory matches the staging area.

3. Final Answer:

   You already staged the changes with git add -> Option C

4. Quick Check:

   Staged changes hide from git diff output [OK]

Hint: No git diff output? Check if changes are staged [OK]

Common Mistakes:

• Thinking git diff shows staged changes
• Assuming untracked files appear in git diff
• Confusing detached HEAD with diff output

5. You want to review all your unstaged changes in the project but exclude changes in the docs/ folder. Which command will help you achieve this?

hard

A. git diff -- . ':!docs/'

B. git diff --exclude=docs/

C. git diff --ignore docs/

D. git diff --skip docs/

Solution

1. Step 1: Understand how to exclude paths in git diff

   Git supports pathspecs with negation using :!path syntax to exclude files or folders.

2. Step 2: Apply exclusion to docs/ folder

   The correct command uses git diff -- . ':!docs/' to show all changes except those in docs/.

3. Final Answer:

   git diff -- . ':!docs/' -> Option A

4. Quick Check:

   Use pathspec negation ':!folder/' to exclude [OK]

Hint: Use git diff with ':!folder/' to exclude paths [OK]

Common Mistakes:

• Using unsupported flags like --exclude or --ignore
• Trying --skip which is invalid
• Not using pathspec syntax for exclusion