git diff between branches - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the command git diff branch1 branch2 do?

It shows the differences between the files in branch1 and branch2. You can see what changes exist from one branch to the other.

beginner

How can you see only the names of files that differ between two branches?

Use git diff --name-only branch1 branch2. This lists just the file names that have changes.

intermediate

What is the difference between git diff branch1 branch2 and git diff branch2 branch1?

The output shows changes from the first branch to the second. So switching the order reverses the direction of the diff.

beginner

Can git diff show changes between your current working directory and a branch?

Yes. Use git diff branch_name to see changes between your current files and that branch.

beginner

What does the --stat option do with git diff?

It shows a summary of changes with file names and how many lines were added or removed, instead of full details.

Which command shows the detailed differences between two branches?

A git diff branch1 branch2

B git status

C git log

D git checkout branch1

git diff branch1 branch2 shows the line-by-line differences between two branches.

How do you list only the files that differ between two branches?

A git branch --list

B git diff --stat branch1 branch2

C git diff --name-only branch1 branch2

D git diff --cached

The --name-only option lists just the file names that differ.

What happens if you swap the branch order in git diff branch1 branch2 to git diff branch2 branch1?

A No difference in output

B The diff output reverses, showing changes from branch2 to branch1

C It merges the branches

D It deletes branch1

The diff direction reverses, showing changes from the first branch to the second.

Which command shows a summary of changes with line counts between branches?

A git diff --name-only branch1 branch2

B git log --stat

C git diff --cached

D git diff --stat branch1 branch2

--stat shows a summary with lines added and removed per file.

Can git diff branch_name show changes between your current files and a branch?

A Yes

B No

C Only if you commit first

D Only if branches are merged

This command compares your current working directory to the specified branch.

Explain how to use git diff to compare two branches and what the output means.

Think about comparing two versions of a document to see what changed.

Describe how to get a quick list of files that differ between two branches without full details.

Imagine checking which chapters changed without reading the whole text.

Practice

1. What does the command git diff branch1 branch2 show you?

easy

A. The commit history of branch1

B. The list of branches in the repository

C. The differences in code between branch1 and branch2

D. The status of files in the current branch

Solution

1. Step 1: Understand the purpose of git diff

   The git diff command compares changes between two points in Git, such as branches.

2. Step 2: Identify what comparing two branches means

   Comparing branch1 and branch2 shows the code differences between them.

3. Final Answer:

   The differences in code between branch1 and branch2 -> Option C

4. Quick Check:

   git diff branch1 branch2 = code differences [OK]

Hint: git diff between branches shows code changes [OK]

Common Mistakes:

• Thinking it shows commit history
• Confusing with git branch command
• Expecting file status instead of differences

2. Which of the following is the correct syntax to see differences between two branches named main and feature?

easy

A. git diff main feature

B. git diff --branches main feature

C. git diff feature..main

D. git diff main..feature

Solution

1. Step 1: Recall git diff syntax for branches

   The basic syntax is git diff branch1 branch2 without dots or extra flags.

2. Step 2: Evaluate each option

   git diff main feature uses git diff main feature, which is correct. Options A and C use double dots which is incorrect for git diff. git diff --branches main feature uses a non-existent flag.

3. Final Answer:

   git diff main feature -> Option A

4. Quick Check:

   Correct syntax = git diff main feature [OK]

Hint: Use 'git diff branch1 branch2' without dots [OK]

Common Mistakes:

• Using double dots '..' with git diff
• Adding unsupported flags like --branches
• Swapping branch order without reason

3. Given two branches, main and dev, where dev has added a new line console.log('Hello'); in app.js, what will git diff main dev show?

medium

A. An error message about branch names

B. A line removed: -console.log('Hello');

C. No output because branches are the same

D. A line added: +console.log('Hello');

Solution

1. Step 1: Understand what git diff shows for added lines

   When a line is added in the second branch, git diff shows it with a plus sign (+).

2. Step 2: Apply to the example

   The new line console.log('Hello'); added in dev will appear as a line starting with + in the diff output.

3. Final Answer:

   A line added: +console.log('Hello'); -> Option D

4. Quick Check:

   Added lines show with + in git diff [OK]

Hint: Added lines show with + in git diff output [OK]

Common Mistakes:

• Thinking added lines show with -
• Expecting no output for changes
• Confusing branch order in diff

4. You run git diff main feature but get no output even though you know feature has changes. What is a likely reason?

medium

A. You forgot to commit changes in feature branch

B. The branches have no differences

C. You are currently on the feature branch

D. You used the wrong command syntax

Solution

1. Step 1: Understand git diff compares committed changes

   Git diff between branches compares committed differences, not uncommitted changes.

2. Step 2: Identify why no output appears

   If changes are not committed in feature, git diff won't show them when comparing branches.

3. Final Answer:

   You forgot to commit changes in feature branch -> Option A

4. Quick Check:

   Uncommitted changes not shown in branch diff [OK]

Hint: Only committed changes appear in git diff between branches [OK]

Common Mistakes:

• Expecting uncommitted changes to show
• Confusing current branch with diff branches
• Assuming syntax error without checking commits

5. You want to review all changes between release and hotfix branches but only for files in the src/ folder. Which command correctly shows this?

hard

A. git diff release..hotfix src/

B. git diff release hotfix -- src/

C. git diff --src release hotfix

D. git diff release hotfix --path src/

Solution

1. Step 1: Understand how to limit git diff to a folder

   Git diff allows specifying paths after a double dash -- to limit output to those files or folders.

2. Step 2: Check each option for correct syntax

   git diff release hotfix -- src/ uses git diff release hotfix -- src/, which correctly limits diff to src/. git diff release..hotfix src/ uses double dots incorrectly. Options C and D use invalid flags.

3. Final Answer:

   git diff release hotfix -- src/ -> Option B

4. Quick Check:

   Use -- then folder to limit git diff [OK]

Hint: Use -- then folder path to filter git diff output [OK]

Common Mistakes:

• Using double dots '..' with git diff
• Adding unsupported flags like --src or --path
• Placing folder path before branch names