git blame for line-by-line history - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to show who last changed each line in a file named README.md.

Git

git [1] README.md

Drag options to blanks, or click blank then click option'

Ablame

Bstatus

Clog

Ddiff

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'git log' instead of 'git blame' to see line history.

Using 'git status' which shows file changes but not line history.

The git blame command shows line-by-line history of changes in a file.

2fill in blank

medium

Complete the command to show blame info for line 10 only in file app.py.

Git

git blame -L [1],[2] app.py

Drag options to blanks, or click blank then click option'

A10,10

B1,10

C10,20

D5,10

Attempts:

3 left

💡 Hint

Common Mistakes

Using a range that includes multiple lines instead of just one.

Forgetting to specify both start and end line numbers.

The -L option limits blame output to specific lines. To show only line 10, use -L 10,10.

3fill in blank

hard

Fix the error in the command to show blame for file main.c in porcelain format.

Git

git blame --[1] main.c

Drag options to blanks, or click blank then click option'

Aauthor-name

Bshow-author

Cporcelain

Dname-only

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect option names like '--show-author' or '--name-only'.

Using single dash instead of double dashes.

The correct option to show blame in porcelain format is --porcelain.

4fill in blank

hard

Fill both blanks to limit blame output to lines 5 to 15 and ignore whitespace changes.

Git

git blame -L [1],[2] --[3] file.txt

Drag options to blanks, or click blank then click option'

A5

B15

Cignore-whitespace

Dignore-all-space

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong line numbers or reversed order.

Using incorrect whitespace ignore options.

Use -L 5,15 to limit lines and --ignore-whitespace to ignore whitespace changes.

5fill in blank

hard

Fill all three blanks to show blame for file server.js, limit to lines 20-30, in porcelain format with abbreviated commit hashes.

Git

git blame [1] [2] [3] server.js

Drag options to blanks, or click blank then click option'

A-L 20,30

B--porcelain

C--abbrev

D--show-name

Attempts:

3 left

💡 Hint

Common Mistakes

Using options in wrong order or missing line limit.

Confusing options that show author names instead of hashes.

-L 20,30 limits lines, --porcelain shows detailed info, and --abbrev shortens commit hashes.

Practice

1. What does the git blame command primarily show?

easy

A. Who last changed each line in a file

B. The current status of the repository

C. The list of branches in the repository

D. The commit history summary

Solution

1. Step 1: Understand the purpose of git blame

   git blame is used to show the author information for each line in a file, indicating who last modified that line.

2. Step 2: Compare with other git commands

   Other commands like git status, git branch, and git log serve different purposes, not line-by-line author tracking.

3. Final Answer:

   Who last changed each line in a file -> Option A

4. Quick Check:

   git blame = line author info [OK]

Hint: Remember: blame = who changed each line last [OK]

Common Mistakes:

• Confusing git blame with git log
• Thinking git blame shows branch info
• Assuming git blame shows file status

2. Which of the following is the correct syntax to show blame for a file named app.js?

easy

A. git blame --file app.js

B. git blame app.js

C. git blame --show app.js

D. git blame -f app.js

Solution

1. Step 1: Recall basic git blame syntax

   The basic syntax to run blame on a file is simply git blame <filename>. No extra flags are needed for a simple blame.

2. Step 2: Check the options given

   Options like -f, --show, or --file are not valid or required for basic blame usage.

3. Final Answer:

   git blame app.js -> Option B

4. Quick Check:

   Basic blame = git blame filename [OK]

Hint: Use just 'git blame filename' for simple blame [OK]

Common Mistakes:

• Adding unnecessary flags
• Using incorrect or unsupported options
• Confusing blame syntax with other git commands

3. Given the command git blame -L 10,15 README.md, what will it show?

medium

A. Blame info for lines 1 to 15 of README.md

B. Blame info for the whole README.md file

C. Blame info for lines 10 to 15 of README.md

D. An error because -L requires a commit hash

Solution

1. Step 1: Understand the -L option in git blame

   The -L option limits the blame output to a specific line range. Here, -L 10,15 means lines 10 through 15.

2. Step 2: Apply to the file README.md

   The command will show blame info only for lines 10 to 15 of the file README.md, not the entire file or any other range.

3. Final Answer:

   Blame info for lines 10 to 15 of README.md -> Option C

4. Quick Check:

   -L limits lines = lines 10-15 [OK]

Hint: -L start,end shows blame only for those lines [OK]

Common Mistakes:

• Assuming -L shows whole file blame
• Thinking -L needs a commit hash
• Confusing line numbers with byte offsets

4. You run git blame --since=2.weeks README.md but get an error. What is the likely cause?

medium

A. You need to specify a commit hash with --since

B. README.md file does not exist

C. Incorrect date format for --since option

D. git blame does not support --since option

Solution

1. Step 1: Check if git blame supports --since

   The git blame command does not have a --since option. This option is valid for git log but not for blame.

2. Step 2: Understand the error cause

   Using an unsupported option causes git blame to error out. The file existence or commit hash is unrelated here.

3. Final Answer:

   git blame does not support --since option -> Option D

4. Quick Check:

   git blame lacks --since option [OK]

Hint: git blame has no --since; use git log for date filters [OK]

Common Mistakes:

• Assuming git blame supports --since
• Blaming file existence without checking
• Thinking commit hash is mandatory with --since

5. You want to find who last changed line 42 in server.py but only for commits on the feature branch. Which command correctly achieves this?

hard

A. git blame feature -- server.py -L 42,42

B. git blame -L 42,42 server.py feature

C. git blame -L 42,42 -- server.py feature

D. git blame -L 42,42 --first-parent feature -- server.py

Solution

1. Step 1: Understand branch limitation in git blame

   To blame a file as it appears on a specific branch, specify the branch name before the -- separator, then the file name.

2. Step 2: Apply line range and branch correctly

   The correct syntax is git blame <branch> -- <file> -L <start,end>. So git blame feature -- server.py -L 42,42 limits blame to line 42 on the feature branch.

3. Final Answer:

   git blame feature -- server.py -L 42,42 -> Option A

4. Quick Check:

   Branch before --, file after, -L for lines [OK]

Hint: Put branch before --, file after, use -L for lines [OK]

Common Mistakes:

• Placing branch after file name
• Misordering -L option
• Using unsupported options like --first-parent with blame