How to use the command 'git commit-tree' (with examples)

The ‘git commit-tree’ command is a low-level utility in Git that is used to create commit objects. It is typically used in scripts or by advanced Git users who need fine-grained control over the creation of commit objects.

Use case 1: Create a commit object with the specified message

Code:

git commit-tree tree -m "message"

Motivation: This use case allows you to create a commit object with a specific commit message. It can be useful when you want to programmatically create commits with predefined messages.

Explanation:

• tree: The SHA-1 tree object of the commit. This specifies the state of the project at the time of the commit.
• -m "message": The commit message to be associated with the commit object.

Example output:

[sha-1]

Use case 2: Create a commit object reading the message from a file

Code:

git commit-tree tree -F path/to/file

Motivation: This use case is useful when you have a commit message stored in a file and want to use it for creating a commit object.

Explanation:

• tree: The SHA-1 tree object of the commit.
• -F path/to/file: Read the commit message from a file. Use a hyphen ("-") for stdin.

Example output:

[sha-1]

Use case 3: Create a GPG-signed commit object

Code:

git commit-tree tree -m "message" --gpg-sign

Motivation: Signing commits with GPG provides a way to verify the authenticity and integrity of a commit object. This use case allows you to create a GPG-signed commit object.

Explanation:

• tree: The SHA-1 tree object of the commit.
• -m "message": The commit message.
• --gpg-sign: Sign the commit object with GPG.

Example output:

[sha-1]

Use case 4: Create a commit object with the specified parent commit object

Code:

git commit-tree tree -m "message" -p parent_commit_sha

Motivation: When creating a new commit, it can be useful to explicitly specify the parent commit object. This use case allows you to create a commit object with a specific parent commit.

Explanation:

• tree: The SHA-1 tree object of the commit.
• -m "message": The commit message.
• -p parent_commit_sha: The SHA-1 of the parent commit object.

Example output:

[sha-1]

Conclusion:

The ‘git commit-tree’ command is a powerful low-level utility in Git that allows you to create commit objects with various options. It is particularly useful for scripting or advanced usage scenarios where fine-grained control over commit creation is required.