git cat-file to inspect objects - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Inspecting a commit object with git cat-file

You have a commit hash abc1234. What is the output type when you run git cat-file -t abc1234?

Git

git cat-file -t abc1234

A commit

B blob

C tree

D tag

💡 Hint

The -t option shows the type of the object.

The git cat-file -t command outputs the type of the object identified by the hash. For a commit hash, the type is always commit.

💻 Command Output

intermediate

Viewing the content of a blob object

You want to see the content of a file stored as a blob object with hash def5678. Which command shows the file content?

Git

git cat-file -p def5678

A git cat-file -s def5678

B git cat-file -t def5678

C git cat-file -p def5678

D git cat-file -e def5678

💡 Hint

The -p option pretty-prints the object content.

Using git cat-file -p on a blob object prints the actual file content stored in that object.

❓ Troubleshoot

advanced

Error when inspecting a non-existent object

You run git cat-file -p 1234567 but get the error: fatal: Not a valid object name 1234567. What is the most likely cause?

Git

git cat-file -p 1234567

A The repository is corrupted and cannot read objects

B You used the wrong option; -p is invalid

C You need to run git fetch before using git cat-file

D The object hash 1234567 does not exist in the repository

💡 Hint

Check if the hash exists in the repo.

The error means the object hash is not found in the repository. It might be mistyped or missing.

🧠 Conceptual

advanced

Understanding git cat-file -s output

What does the command git cat-file -s 9a8b7c6 output?

Git

git cat-file -s 9a8b7c6

A The type of the object identified by 9a8b7c6

B The size in bytes of the object identified by 9a8b7c6

C The content of the object identified by 9a8b7c6

D The commit message of the commit object 9a8b7c6

💡 Hint

The -s option shows size.

The -s option prints the size in bytes of the object content stored in Git.

✅ Best Practice

expert

Using git cat-file in a script to check object type

You want a script to check if a given hash is a tree object. Which command correctly returns true if the object is a tree, and false otherwise?

A test "$(git cat-file -t $HASH)" = "tree" && echo true || echo false

B if git cat-file -p $HASH | grep -q tree; then echo true; else echo false; fi

C git cat-file -s $HASH | grep tree && echo true || echo false

D git cat-file -e $HASH && echo true || echo false

💡 Hint

Use -t to get the object type exactly.

Option A compares the output of git cat-file -t to 'tree' exactly, returning true or false accordingly. Other options either check content or existence, not type.