cat-file Git Command Guide

The git cat-file command is used to provide contents or details of repository objects, operating in two modes: non-batch mode for single object queries, and batch mode for processing multiple objects from standard input.

git cat-file Syntax:

git cat-file <type> <object>

git cat-file (-e | -p | -t | -s) <object>

git cat-file (--textconv | --filters)
             [<rev>:<path|tree-ish> | --path=<path|tree-ish> <rev>]

git cat-file (--batch | --batch-check | --batch-command) [--batch-all-objects]
             [--buffer] [--follow-symlinks] [--unordered]
             [--textconv | --filters] [-Z]

Options:

Option	Description
-t	Instead of the content, show the object type identified by
-s	Instead of the content, show the object size identified by
-e	Exit with zero status if
-p	Pretty-print the contents of
—[no-]mailmap, —[no-]use-mailmap	Use mailmap file to map author, committer and tagger names and email addresses
—textconv	Show the content as transformed by a textconv filter
—filters	Show the content as converted by the filters configured in the current working tree
—filter=, —no-filter	Omit objects from the list of printed objects (batch modes only)
—path=	For use with —textconv or —filters, to allow specifying an object name and a path separately
—batch, —batch=	Print object information and contents for each object provided on stdin
—batch-check, —batch-check=	Print object information for each object provided on stdin
—batch-command, —batch-command=	Enter a command mode that reads commands and arguments from stdin
—batch-all-objects	Perform the requested batch operation on all objects in the repository
—buffer	Use normal stdio buffering; more efficient for processing many objects
—unordered	Visit objects in an unspecified order which may be more efficient
—follow-symlinks	Follow symlinks inside the repository when requesting objects with extended SHA-1 expressions
-Z	Use NUL-delimited input and output instead of newline-delimited

Parameters:

Parameter	Description
	The name of the object to show
	Typically this matches the real type of

Caution

cat-file operates on raw Git objects and doesn’t validate object formats before processing. Use with caution when working directly with object hashes, and always verify objects exist with -e first.

git cat-file Command Samples:

Show the type of an object

git cat-file -t HEAD

Gets the object type of the commit pointed to by HEAD.

Show the size of a blob object

git cat-file -s HEAD:README.md

Displays the size in bytes of the README.md file in the HEAD commit.

Pretty-print a commit object

git cat-file -p HEAD

Displays the full commit information including author, date, message, and tree hash.

Check if an object exists

git cat-file -e abc123

Returns exit code 0 if object exists, non-zero otherwise.

Batch mode to process multiple objects

echo "HEAD^{tree}" | git cat-file --batch

Takes object from stdin and outputs SHA, type, size, and contents.

Show content with filters applied

git cat-file --filters HEAD:script.py

Shows the content of script.py from HEAD after applying configured filters.

Tip

Use git rev-parse to convert refs to SHA-1 or check git log --oneline for commit SHAs before using cat-file.

How do I view the raw content of a Git object?

To view the raw content of a Git object, use:

git cat-file <type> <object>

How can I check if a Git object exists?

To check if a Git object exists, run:

git cat-file -e <object>

How do I display the type of a Git object?

To display the type of a Git object, execute:

git cat-file -t <object>

How can I see the size of a Git object?

To see the size of a Git object, use:

git cat-file -s <object>

How do I pretty-print Git object contents?

To pretty-print Git object contents, run:

git cat-file -p <object>

How can I process multiple objects in batch mode?

To process multiple objects in batch mode, use:

echo "<object>" | git cat-file --batch

Applications of the git cat-file command

1. Inspecting the raw contents of Git objects for debugging repository issues
2. Checking object types and sizes to understand repository structure
3. Pretty-printing commit, tree, and blob objects for analysis
4. Validating object existence before processing in scripts
5. Processing large numbers of objects efficiently in batch mode
6. Applying text conversion filters to content during inspection
7. Following symlinks within the repository structure