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:
-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. 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:
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:
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:
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:
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.
