git log formatting options - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of git log with custom format

What is the output of the following command if the latest commit hash is abc1234 and the commit message is Initial commit?

Git

git log -1 --pretty=format:"%h - %s"

A commit abc1234 - Initial commit

B Initial commit - abc1234

C abc1234 - Initial commit

D abc1234 Initial commit

💡 Hint

The format string uses %h for short hash and %s for subject.

The --pretty=format:"%h - %s" option prints the short commit hash followed by a dash and the commit message subject.

🧠 Conceptual

intermediate

Understanding git log placeholders

Which placeholder in git log --pretty=format: shows the author date in ISO 8601 format?

A %ai

B %ad

C %cd

D %ci

💡 Hint

Look for the placeholder ending with 'i' for ISO format.

%ai shows the author date in strict ISO 8601 format. %ad shows author date but in a format that can be customized.

❓ Troubleshoot

advanced

Troubleshooting git log format syntax error

You run git log --pretty=format:"%h %s and get a syntax error. What is the cause?

Git

git log --pretty=format:"%h %s

A git log does not support --pretty=format option

B Missing closing double quote for the format string

C The commit message %s is not allowed here

D Invalid placeholder %h

💡 Hint

Check if the quotes are balanced.

The command is missing the closing double quote, causing the shell or git to report a syntax error.

✅ Best Practice

advanced

Best practice for showing commit date and author

Which git log format string best shows the commit hash, author name, and commit date in ISO format on one line?

A %h %an %ai

B %h %an %ad

C %H %an %ai

D %h %ae %cd

💡 Hint

Use short hash and author name with ISO date.

%h is short hash, %an is author name, and %ai is author date in ISO 8601 format, making option A the best choice.

🔀 Workflow

expert

Creating a custom git log alias with formatting

You want to create a git alias named summary that shows each commit's short hash, author, and subject in one line. Which command correctly sets this alias?

A git config --global alias.summary "log --pretty=format:%h %an %s"

B git config --global alias.summary "log --pretty=format:\"%h %an %s\""

C git config --global alias.summary "log --pretty=format:'%h %an %s'"

D git config --global alias.summary 'log --pretty=format:"%h %an %s"'

💡 Hint

Remember to properly quote the format string inside the alias.

Option D correctly uses single quotes around the entire argument and double quotes inside for the format string, avoiding shell parsing issues.

Practice

1. What does the %h placeholder represent in git log --pretty=format:"%h %s"?

easy

A. Author name

B. Abbreviated commit hash

C. Commit date

D. Full commit message

Solution

1. Step 1: Understand %h in git log format

   The placeholder %h stands for the abbreviated commit hash, a short version of the commit ID.

2. Step 2: Compare with other placeholders

   %an is author name, %cd is commit date, and %s is the commit message. So %h is unique for the commit hash.

3. Final Answer:

   Abbreviated commit hash -> Option B

4. Quick Check:

   Commit hash short form [OK]

Hint: Remember: %h = short hash, %an = author name [OK]

Common Mistakes:

• Confusing %h with %an (author name)
• Thinking %h shows full commit message
• Mixing %h with commit date placeholder

2. Which of the following is the correct syntax to show the author name followed by commit message using git log --pretty=format?

easy

A. git log --pretty=format:"%an %s"

B. git log --pretty=format:"%s %an"

C. git log --pretty=format:"%author %message"

D. git log --pretty=format:"%name %subject"

Solution

1. Step 1: Identify correct placeholders for author and message

   The correct placeholders are %an for author name and %s for commit message.

2. Step 2: Check syntax correctness

   git log --pretty=format:"%an %s" uses %an %s which is valid. Options A and C use invalid placeholders. git log --pretty=format:"%s %an" reverses order but is still valid syntax, but question asks for author then message.

3. Final Answer:

   git log --pretty=format:"%an %s" -> Option A

4. Quick Check:

   Author then message [OK]

Hint: Use %an for author, %s for message in format string [OK]

Common Mistakes:

• Using invalid placeholders like %author or %message
• Swapping order when question specifies author first
• Missing quotes around format string

3. What will be the output of this command if the latest commit hash is abc1234, author is Jane, and message is Fix bug?

git log -1 --pretty=format:"%h - %an: %s"

medium

A. Fix bug - Jane: abc1234

B. abc1234 Jane Fix bug

C. Jane - abc1234: Fix bug

D. abc1234 - Jane: Fix bug

Solution

1. Step 1: Understand placeholders in format string

   The format string is %h - %an: %s. %h is abbreviated hash, %an is author name, %s is commit message.

2. Step 2: Substitute given values

   Replacing placeholders: %h = abc1234, %an = Jane, %s = Fix bug. So output is "abc1234 - Jane: Fix bug".

3. Final Answer:

   abc1234 - Jane: Fix bug -> Option D

4. Quick Check:

   Format placeholders replaced correctly [OK]

Hint: Match placeholders to values exactly in order [OK]

Common Mistakes:

• Mixing order of placeholders and values
• Ignoring separators like '-' and ':'
• Confusing full hash with abbreviated hash

4. You run git log --pretty=format:"%h %an %msg" but get an error. What is the problem?

medium

A. The placeholder %msg is invalid

B. Missing quotes around format string

C. Using %h and %an together is not allowed

D. Command needs --oneline option

Solution

1. Step 1: Identify invalid placeholder

   The placeholder %msg does not exist in git log formatting. The correct placeholder for commit message is %s.

2. Step 2: Check other parts of command

   Quotes are present, and using %h and %an together is valid. The --oneline option is optional and unrelated to this error.

3. Final Answer:

   The placeholder %msg is invalid -> Option A

4. Quick Check:

   Invalid placeholder causes error [OK]

Hint: Use %s for message, not %msg [OK]

Common Mistakes:

• Typing %msg instead of %s
• Forgetting quotes around format string
• Assuming --oneline is required for formatting

5. You want to list commits showing only the abbreviated hash, author email, and commit date in ISO format. Which command achieves this?

hard

A. git log --pretty=format:"%h %an %cd" --date=short

B. git log --pretty=format:"%H %ae %cd" --date=iso

C. git log --pretty=format:"%h %ae %cd" --date=iso

D. git log --pretty=format:"%h %ae %cd" --date=relative

Solution

1. Step 1: Identify placeholders for required info

   %h is abbreviated hash, %ae is author email, %cd is commit date.

2. Step 2: Choose correct date format option

   --date=iso shows date in ISO 8601 format, which matches requirement.

3. Step 3: Verify options

   git log --pretty=format:"%h %ae %cd" --date=iso matches all requirements. git log --pretty=format:"%h %an %cd" --date=short uses %an (author name) and short date, not email or ISO. git log --pretty=format:"%H %ae %cd" --date=iso uses %H (full hash), not abbreviated. git log --pretty=format:"%h %ae %cd" --date=relative uses relative date format, not ISO.

4. Final Answer:

   git log --pretty=format:"%h %ae %cd" --date=iso -> Option C

5. Quick Check:

   Abbreviated hash, email, ISO date [OK]

Hint: Use %ae for email and --date=iso for ISO date format [OK]

Common Mistakes:

• Using %an instead of %ae for email
• Choosing wrong date format option
• Using full hash %H instead of abbreviated %h