Why staging before committing matters in Git - Why It Works

Introduction

When you make changes to files in a project, you often want to choose which changes to save permanently. Staging lets you pick exactly what to include before saving it with a commit. This helps keep your project history clean and organized.

When you have multiple changes but want to save only some of them in a commit

When you want to review changes before saving them permanently

When you want to group related changes together in separate commits

When you want to avoid committing temporary or experimental edits

When you want to prepare a commit step-by-step instead of all at once

Commands

Check which files have changes and which are staged or unstaged. This helps you see what is ready to be committed.

Terminal

git status

Expected Output

On branch main

Changes not staged for commit:

  (use "git add <file>..." to update what will be committed)

  (use "git restore <file>..." to discard changes in working directory)



	modified:   example.txt



no changes added to commit (use "git add" and/or "git commit -a")

Stage the changes in example.txt so they will be included in the next commit. This lets you control exactly what to save.

Terminal

git add example.txt

Expected Output

No output (command runs silently)

Verify that example.txt is now staged and ready to be committed.

Terminal

git status

Expected Output

On branch main

Changes to be committed:

  (use "git restore --staged <file>..." to unstage)



	modified:   example.txt

Create a commit with the staged changes and a message describing what was done. This saves your work permanently in the project history.

Terminal

git commit -m "Update example.txt with new info"

Expected Output

[main abc1234] Update example.txt with new info

 1 file changed, 3 insertions(+), 1 deletion(-)

→

-m - Add a commit message inline without opening an editor

Key Concept

Staging lets you choose exactly which changes to save in a commit, keeping your project history clear and organized.

Common Mistakes

Committing without staging first using 'git commit -a' or no staging

This commits all changes automatically, which can include unwanted edits and makes history messy.

Use 'git add' to stage only the changes you want before committing.

Not checking 'git status' before committing

You might commit incomplete or wrong files without realizing it.

Always run 'git status' to review staged and unstaged changes before committing.

Summary

Use 'git add' to stage specific changes before committing.

Check 'git status' to see what is staged and unstaged.

Commit only staged changes with 'git commit' to keep history clean.

Practice

1. Why is staging changes before committing important in Git?

easy

A. It automatically pushes changes to the remote repository.

B. It lets you choose which changes to include in the next commit.

C. It deletes untracked files from the working directory.

D. It merges branches without conflicts.

Solution

1. Step 1: Understand the role of staging

   Staging allows you to select specific changes to include in your next commit, rather than committing all changes at once.

2. Step 2: Compare staging with other Git actions

   Staging does not push changes, delete files, or merge branches; it only prepares changes for commit.

3. Final Answer:

   It lets you choose which changes to include in the next commit. -> Option B

4. Quick Check:

   Staging = Select changes before commit [OK]

Hint: Staging = picking changes to commit, not pushing or deleting [OK]

Common Mistakes:

• Confusing staging with pushing changes
• Thinking staging deletes files
• Believing staging merges branches

2. Which Git command correctly stages a file named index.html?

easy

A. git add index.html

B. git push index.html

C. git commit index.html

D. git status index.html

Solution

1. Step 1: Identify the command to stage files

   The git add command is used to stage files before committing.

2. Step 2: Verify other commands' purposes

   git commit records changes, git push sends commits to remote, and git status shows current status; none stage files.

3. Final Answer:

   git add index.html -> Option A

4. Quick Check:

   Stage file = git add [OK]

Hint: Use 'git add' to stage files before commit [OK]

Common Mistakes:

• Using git commit to stage files
• Confusing git push with staging
• Thinking git status stages files

3. Given these commands run in order:

echo 'Hello' > file.txt
git add file.txt
echo 'World' >> file.txt
git commit -m 'Add greeting'

What will be included in the commit?

medium

A. Only 'World' line in file.txt

B. Both 'Hello' and 'World' lines in file.txt

C. Only 'Hello' line in file.txt

D. An empty file.txt

Solution

1. Step 1: Understand staging timing

   The first echo creates file.txt with 'Hello'. Then git add stages this version.

2. Step 2: Changes after staging are not included

   Appending 'World' happens after staging, so this change is not in the commit.

3. Final Answer:

   Only 'Hello' line in file.txt -> Option C

4. Quick Check:

   Commit = staged snapshot, later edits excluded [OK]

Hint: Commit includes only staged changes, not later edits [OK]

Common Mistakes:

• Assuming commit includes all current file content
• Ignoring that staging freezes file state
• Thinking commit auto-stages changes

4. You staged a file with git add app.js but accidentally modified it afterward. What should you do to include the latest changes in your commit?

medium

A. Run git commit immediately

B. Run git reset app.js to unstage

C. Run git push to update remote

D. Run git add app.js again

Solution

1. Step 1: Recognize staging snapshot behavior

   Staging captures the file state at the time of git add. Later edits are not staged automatically.

2. Step 2: Stage the updated file again

   To include the latest changes, you must run git add app.js again to update the staging area.

3. Final Answer:

   Run git add app.js again -> Option D

4. Quick Check:

   Restage after edits to update commit content [OK]

Hint: Restage files after edits before committing [OK]

Common Mistakes:

• Committing without restaging changes
• Pushing before committing
• Unstaging instead of restaging

5. You have modified three files: index.html, style.css, and script.js. You want to commit only index.html and script.js changes but not style.css. Which sequence of commands achieves this?

hard

A. git add index.html script.js && git commit -m 'Partial commit'

B. git add . && git commit -m 'Partial commit'

C. git commit -a -m 'Partial commit'

D. git add style.css && git commit -m 'Partial commit'

Solution

1. Step 1: Understand selective staging

   To commit only specific files, stage only those files explicitly with git add.

2. Step 2: Analyze each option

   git add . && git commit -m 'Partial commit' stages all changes (including style.css). git commit -a -m 'Partial commit' commits all tracked changes automatically, including style.css. git add style.css && git commit -m 'Partial commit' stages only style.css, which is unwanted.

3. Final Answer:

   git add index.html script.js && git commit -m 'Partial commit' -> Option A

4. Quick Check:

   Select files with git add before commit [OK]

Hint: Stage only desired files before commit to exclude others [OK]

Common Mistakes:

• Using git add . to stage all files
• Using git commit -a which stages all tracked files
• Staging unwanted files by mistake