GIT-CAT-FILE(1) Git Manual GIT-CAT-FILE(1)
NAME
git-cat-file - Provide contents or details of repository objects
SYNOPSIS
git cat-file <type> <object>
git cat-file (-e | -p) <object>
git cat-file (-t | -s) [--allow-unknown-type] <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]
DESCRIPTION
Output the contents or other properties such as size, type or delta
information of one or more objects.
This command can operate in two modes, depending on whether an option
from the --batch family is specified.
In non-batch mode, the command provides information on an object named
on the command line.
In batch mode, arguments are read from standard input.
OPTIONS
<object>
The name of the object to show. For a more complete list of ways to
spell object names, see the "SPECIFYING REVISIONS" section in
gitrevisions(7).
-t
Instead of the content, show the object type identified by <object>.
-s
Instead of the content, show the object size identified by <object>.
If used with --use-mailmap option, will show the size of updated
object after replacing idents using the mailmap mechanism.
-e
Exit with zero status if <object> exists and is a valid object. If
<object> is of an invalid format, exit with non-zero status and emit
an error on stderr.
-p
Pretty-print the contents of <object> based on its type.
<type>
Typically this matches the real type of <object> but asking for a
type that can trivially be dereferenced from the given <object> is
also permitted. An example is to ask for a "tree" with <object>
being a commit object that contains it, or to ask for a "blob" with
<object> being a tag object that points at it.
--[no-]mailmap, --[no-]use-mailmap
Use mailmap file to map author, committer and tagger names and email
addresses to canonical real names and email addresses. See git-
shortlog(1).
--textconv
Show the content as transformed by a textconv filter. In this case,
<object> has to be of the form <tree-ish>:<path>, or :<path> in
order to apply the filter to the content recorded in the index at
<path>.
--filters
Show the content as converted by the filters configured in the
current working tree for the given <path> (i.e. smudge filters,
end-of-line conversion, etc). In this case, <object> has to be of
the form <tree-ish>:<path>, or :<path>.
--path=<path>
For use with --textconv or --filters, to allow specifying an object
name and a path separately, e.g. when it is difficult to figure out
the revision from which the blob came.
--batch, --batch=<format>
Print object information and contents for each object provided on
stdin. May not be combined with any other options or arguments
except --textconv, --filters, or --use-mailmap.
• When used with --textconv or --filters, the input lines must
specify the path, separated by whitespace. See the section BATCH
OUTPUT below for details.
• When used with --use-mailmap, for commit and tag objects, the
contents part of the output shows the identities replaced using
the mailmap mechanism, while the information part of the output
shows the size of the object as if it actually recorded the
replacement identities.
--batch-check, --batch-check=<format>
Print object information for each object provided on stdin. May not
be combined with any other options or arguments except --textconv,
--filters or --use-mailmap.
• When used with --textconv or --filters, the input lines must
specify the path, separated by whitespace. See the section BATCH
OUTPUT below for details.
• When used with --use-mailmap, for commit and tag objects, the
printed object information shows the size of the object as if
the identities recorded in it were replaced by the mailmap
mechanism.
--batch-command, --batch-command=<format>
Enter a command mode that reads commands and arguments from stdin.
May only be combined with --buffer, --textconv, --use-mailmap or
--filters.
• When used with --textconv or --filters, the input lines must
specify the path, separated by whitespace. See the section BATCH
OUTPUT below for details.
• When used with --use-mailmap, for commit and tag objects, the
contents command shows the identities replaced using the mailmap
mechanism, while the info command shows the size of the object
as if it actually recorded the replacement identities.
--batch-command recognizes the following commands:
contents <object>
Print object contents for object reference <object>. This
corresponds to the output of --batch.
info <object>
Print object info for object reference <object>. This
corresponds to the output of --batch-check.
flush
Used with --buffer to execute all preceding commands that were
issued since the beginning or since the last flush was issued.
When --buffer is used, no output will come until a flush is
issued. When --buffer is not used, commands are flushed each
time without issuing flush.
--batch-all-objects
Instead of reading a list of objects on stdin, perform the requested
batch operation on all objects in the repository and any alternate
object stores (not just reachable objects). Requires --batch or
--batch-check be specified. By default, the objects are visited in
order sorted by their hashes; see also --unordered below. Objects
are presented as-is, without respecting the "replace" mechanism of
git-replace(1).
--buffer
Normally batch output is flushed after each object is output, so
that a process can interactively read and write from cat-file. With
this option, the output uses normal stdio buffering; this is much
more efficient when invoking --batch-check or --batch-command on a
large number of objects.
--unordered
When --batch-all-objects is in use, visit objects in an order which
may be more efficient for accessing the object contents than hash
order. The exact details of the order are unspecified, but if you do
not require a specific order, this should generally result in faster
output, especially with --batch. Note that cat-file will still show
each object only once, even if it is stored multiple times in the
repository.
--allow-unknown-type
Allow -s or -t to query broken/corrupt objects of unknown type.
--follow-symlinks
With --batch or --batch-check, follow symlinks inside the repository
when requesting objects with extended SHA-1 expressions of the form
tree-ish:path-in-tree. Instead of providing output about the link
itself, provide output about the linked-to object. If a symlink
points outside the tree-ish (e.g. a link to /foo or a root-level
link to ../foo), the portion of the link which is outside the tree
will be printed.
This option does not (currently) work correctly when an object in
the index is specified (e.g. :link instead of HEAD:link) rather
than one in the tree.
This option cannot (currently) be used unless --batch or
--batch-check is used.
For example, consider a git repository containing:
f: a file containing "hello\n"
link: a symlink to f
dir/link: a symlink to ../f
plink: a symlink to ../f
alink: a symlink to /etc/passwd
For a regular file f, echo HEAD:f | git cat-file --batch would print
ce013625030ba8dba906f756967f9e9ca394464a blob 6
And echo HEAD:link | git cat-file --batch --follow-symlinks would
print the same thing, as would HEAD:dir/link, as they both point at
HEAD:f.
Without --follow-symlinks, these would print data about the symlink
itself. In the case of HEAD:link, you would see
4d1ae35ba2c8ec712fa2a379db44ad639ca277bd blob 1
Both plink and alink point outside the tree, so they would
respectively print:
symlink 4
../f
symlink 11
/etc/passwd
-Z
Only meaningful with --batch, --batch-check, or --batch-command;
input and output is NUL-delimited instead of newline-delimited.
-z
Only meaningful with --batch, --batch-check, or --batch-command;
input is NUL-delimited instead of newline-delimited. This option is
deprecated in favor of -Z as the output can otherwise be ambiguous.
OUTPUT
If -t is specified, one of the <type>.
If -s is specified, the size of the <object> in bytes.
If -e is specified, no output, unless the <object> is malformed.
If -p is specified, the contents of <object> are pretty-printed.
If <type> is specified, the raw (though uncompressed) contents of the
<object> will be returned.
BATCH OUTPUT
If --batch or --batch-check is given, cat-file will read objects from
stdin, one per line, and print information about them in the same order
as they have been read. By default, the whole line is considered as an
object, as if it were fed to git-rev-parse(1).
When --batch-command is given, cat-file will read commands from stdin,
one per line, and print information based on the command given. With
--batch-command, the info command followed by an object will print
information about the object the same way --batch-check would, and the
contents command followed by an object prints contents in the same way
--batch would.
You can specify the information shown for each object by using a custom
<format>. The <format> is copied literally to stdout for each object,
with placeholders of the form %(atom) expanded, followed by a newline.
The available atoms are:
objectname
The full hex representation of the object name.
objecttype
The type of the object (the same as cat-file -t reports).
objectsize
The size, in bytes, of the object (the same as cat-file -s reports).
objectsize:disk
The size, in bytes, that the object takes up on disk. See the note
about on-disk sizes in the CAVEATS section below.
deltabase
If the object is stored as a delta on-disk, this expands to the full
hex representation of the delta base object name. Otherwise, expands
to the null OID (all zeroes). See CAVEATS below.
rest
If this atom is used in the output string, input lines are split at
the first whitespace boundary. All characters before that whitespace
are considered to be the object name; characters after that first
run of whitespace (i.e., the "rest" of the line) are output in place
of the %(rest) atom.
If no format is specified, the default format is %(objectname)
%(objecttype) %(objectsize).
If --batch is specified, or if --batch-command is used with the contents
command, the object information is followed by the object contents
(consisting of %(objectsize) bytes), followed by a newline.
For example, --batch without a custom format would produce:
<oid> SP <type> SP <size> LF
<contents> LF
Whereas --batch-check='%(objectname) %(objecttype)' would produce:
<oid> SP <type> LF
If a name is specified on stdin that cannot be resolved to an object in
the repository, then cat-file will ignore any custom format and print:
<object> SP missing LF
If a name is specified that might refer to more than one object (an
ambiguous short sha), then cat-file will ignore any custom format and
print:
<object> SP ambiguous LF
If --follow-symlinks is used, and a symlink in the repository points
outside the repository, then cat-file will ignore any custom format and
print:
symlink SP <size> LF
<symlink> LF
The symlink will either be absolute (beginning with a /), or relative to
the tree root. For instance, if dir/link points to ../../foo, then
<symlink> will be ../foo. <size> is the size of the symlink in bytes.
If --follow-symlinks is used, the following error messages will be
displayed:
<object> SP missing LF
is printed when the initial symlink requested does not exist.
dangling SP <size> LF
<object> LF
is printed when the initial symlink exists, but something that it
(transitive-of) points to does not.
loop SP <size> LF
<object> LF
is printed for symlink loops (or any symlinks that require more than 40
link resolutions to resolve).
notdir SP <size> LF
<object> LF
is printed when, during symlink resolution, a file is used as a
directory name.
Alternatively, when -Z is passed, the line feeds in any of the above
examples are replaced with NUL terminators. This ensures that output
will be parsable if the output itself would contain a linefeed and is
thus recommended for scripting purposes.
CAVEATS
Note that the sizes of objects on disk are reported accurately, but care
should be taken in drawing conclusions about which refs or objects are
responsible for disk usage. The size of a packed non-delta object may be
much larger than the size of objects which delta against it, but the
choice of which object is the base and which is the delta is arbitrary
and is subject to change during a repack.
Note also that multiple copies of an object may be present in the object
database; in this case, it is undefined which copy’s size or delta base
will be reported.
GIT
Part of the git(1) suite
Git 2.47.3 07/30/2025 GIT-CAT-FILE(1)
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