diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index bd95a6c10a7d0b..69b50d2042ff2f 100644
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@ -292,6 +292,11 @@ newline. The available atoms are:
 `objecttype`::
 	The type of the object (the same as `cat-file -t` reports).
 
+`objectmode`::
+	If the specified object has mode information (such as a tree or
+	index entry), the mode expressed as an octal integer. Otherwise,
+	empty string.
+
 `objectsize`::
 	The size, in bytes, of the object (the same as `cat-file -s`
 	reports).
@@ -407,6 +412,11 @@ 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.
 
+Submodules are handled specially in `git cat-file`, as the objects
+corresponding to the recorded OIDs are not expected to be present in the
+current repository. For that reason, submodules are reported as having
+type `submodule` and mode 1600000 and all other fields are zeroed out.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index bbf851138ec408..c59ad682d1f6d9 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -128,7 +128,9 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 	switch (opt) {
 	case 't':
 		oi.type_name = &sb;
-		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
+		if (obj_context.mode == S_IFGITLINK)
+			strbuf_addstr(&sb, "submodule");
+		else if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		if (sb.len) {
 			printf("%s\n", sb.buf);
@@ -272,6 +274,7 @@ struct expand_data {
 	struct object_id oid;
 	enum object_type type;
 	unsigned long size;
+	unsigned short mode;
 	off_t disk_size;
 	const char *rest;
 	struct object_id delta_base_oid;
@@ -303,6 +306,7 @@ struct expand_data {
 	 */
 	unsigned skip_object_info : 1;
 };
+#define EXPAND_DATA_INIT  { .mode = S_IFINVALID }
 
 static int is_atom(const char *atom, const char *s, int slen)
 {
@@ -317,17 +321,26 @@ static void expand_atom(struct strbuf *sb, const char *atom, int len,
 		if (!data->mark_query)
 			strbuf_addstr(sb, oid_to_hex(&data->oid));
 	} else if (is_atom("objecttype", atom, len)) {
-		if (data->mark_query)
+		if (data->mode == S_IFGITLINK) {
+			if (!data->mark_query)
+				strbuf_addstr(sb, "submodule");
+		} else if (data->mark_query)
 			data->info.typep = &data->type;
 		else
 			strbuf_addstr(sb, type_name(data->type));
 	} else if (is_atom("objectsize", atom, len)) {
-		if (data->mark_query)
+		if (data->mode == S_IFGITLINK) {
+			if (!data->mark_query)
+				strbuf_addstr(sb, "0");
+		} else if (data->mark_query)
 			data->info.sizep = &data->size;
 		else
 			strbuf_addf(sb, "%"PRIuMAX , (uintmax_t)data->size);
 	} else if (is_atom("objectsize:disk", atom, len)) {
-		if (data->mark_query)
+		if (data->mode == S_IFGITLINK) {
+			if (!data->mark_query)
+				strbuf_addstr(sb, "0");
+		} else if (data->mark_query)
 			data->info.disk_sizep = &data->disk_size;
 		else
 			strbuf_addf(sb, "%"PRIuMAX, (uintmax_t)data->disk_size);
@@ -342,6 +355,9 @@ static void expand_atom(struct strbuf *sb, const char *atom, int len,
 		else
 			strbuf_addstr(sb,
 				      oid_to_hex(&data->delta_base_oid));
+	} else if (is_atom("objectmode", atom, len)) {
+		if (!data->mark_query && !(S_IFINVALID == data->mode))
+			strbuf_addf(sb, "%06o", data->mode);
 	} else
 		die("unknown format element: %.*s", len, atom);
 }
@@ -443,7 +459,8 @@ static void print_default_format(struct strbuf *scratch, struct expand_data *dat
 				 struct batch_options *opt)
 {
 	strbuf_addf(scratch, "%s %s %"PRIuMAX"%c", oid_to_hex(&data->oid),
-		    type_name(data->type),
+		    data->mode == S_IFGITLINK ?
+		    "submodule" : type_name(data->type),
 		    (uintmax_t)data->size, opt->output_delim);
 }
 
@@ -465,7 +482,15 @@ static void batch_object_write(const char *obj_name,
 		if (use_mailmap)
 			data->info.typep = &data->type;
 
-		if (pack)
+		if (data->mode == S_IFGITLINK) {
+			data->type = OBJ_BAD; /* `type_name()` does not know submodules */
+			data->size = 0;
+			data->disk_size = 0;
+			data->rest = NULL;
+			oidcpy(&data->delta_base_oid, null_oid());
+			memset(&data->info, 0, sizeof(data->info));
+			ret = 0; /* no info to look up */
+		} else if (pack)
 			ret = packed_object_info(the_repository, pack, offset,
 						 &data->info);
 		else
@@ -562,6 +587,7 @@ static void batch_one_object(const char *obj_name,
 		return;
 	}
 
+	data->mode = ctx.mode;
 	batch_object_write(obj_name, scratch, opt, data, NULL, 0);
 }
 
@@ -766,7 +792,7 @@ static int batch_objects(struct batch_options *opt)
 {
 	struct strbuf input = STRBUF_INIT;
 	struct strbuf output = STRBUF_INIT;
-	struct expand_data data;
+	struct expand_data data = EXPAND_DATA_INIT;
 	int save_warning;
 	int retval = 0;
 
@@ -775,7 +801,6 @@ static int batch_objects(struct batch_options *opt)
 	 * object_info to be handed to oid_object_info_extended for each
 	 * object.
 	 */
-	memset(&data, 0, sizeof(data));
 	data.mark_query = 1;
 	expand_format(&output,
 		      opt->format ? opt->format : DEFAULT_FORMAT,
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index e0c6482797e120..3368b663ef3fda 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -112,65 +112,67 @@ strlen () {
 
 run_tests () {
     type=$1
-    sha1=$2
-    size=$3
-    content=$4
-    pretty_content=$5
-
-    batch_output="$sha1 $type $size
+    object_name=$2
+    oid=$(git rev-parse --verify $object_name)
+    mode=$3
+    size=$4
+    content=$5
+    pretty_content=$6
+
+    batch_output="$oid $type $size
 $content"
 
     test_expect_success "$type exists" '
-	git cat-file -e $sha1
+	git cat-file -e $object_name
     '
 
     test_expect_success "Type of $type is correct" '
 	echo $type >expect &&
-	git cat-file -t $sha1 >actual &&
+	git cat-file -t $object_name >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "Size of $type is correct" '
 	echo $size >expect &&
-	git cat-file -s $sha1 >actual &&
+	git cat-file -s $object_name >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "Type of $type is correct using --allow-unknown-type" '
 	echo $type >expect &&
-	git cat-file -t --allow-unknown-type $sha1 >actual &&
+	git cat-file -t --allow-unknown-type $object_name >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "Size of $type is correct using --allow-unknown-type" '
 	echo $size >expect &&
-	git cat-file -s --allow-unknown-type $sha1 >actual &&
+	git cat-file -s --allow-unknown-type $object_name >actual &&
 	test_cmp expect actual
     '
 
     test -z "$content" ||
     test_expect_success "Content of $type is correct" '
 	echo_without_newline "$content" >expect &&
-	git cat-file $type $sha1 >actual &&
+	git cat-file $type $object_name >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "Pretty content of $type is correct" '
 	echo_without_newline "$pretty_content" >expect &&
-	git cat-file -p $sha1 >actual &&
+	git cat-file -p $object_name >actual &&
 	test_cmp expect actual
     '
 
     test -z "$content" ||
     test_expect_success "--batch output of $type is correct" '
 	echo "$batch_output" >expect &&
-	echo $sha1 | git cat-file --batch >actual &&
+	echo $object_name | git cat-file --batch >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "--batch-check output of $type is correct" '
-	echo "$sha1 $type $size" >expect &&
-	echo_without_newline $sha1 | git cat-file --batch-check >actual &&
+	echo "$oid $type $size" >expect &&
+	echo_without_newline $object_name | git cat-file --batch-check >actual &&
 	test_cmp expect actual
     '
 
@@ -179,44 +181,50 @@ $content"
 	test -z "$content" ||
 		test_expect_success "--batch-command $opt output of $type content is correct" '
 		echo "$batch_output" >expect &&
-		test_write_lines "contents $sha1" | git cat-file --batch-command $opt >actual &&
+		test_write_lines "contents $object_name" | git cat-file --batch-command $opt >actual &&
 		test_cmp expect actual
 	'
 
 	test_expect_success "--batch-command $opt output of $type info is correct" '
-		echo "$sha1 $type $size" >expect &&
-		test_write_lines "info $sha1" |
+		echo "$oid $type $size" >expect &&
+		test_write_lines "info $object_name" |
 		git cat-file --batch-command $opt >actual &&
 		test_cmp expect actual
 	'
     done
 
     test_expect_success "custom --batch-check format" '
-	echo "$type $sha1" >expect &&
-	echo $sha1 | git cat-file --batch-check="%(objecttype) %(objectname)" >actual &&
+	echo "$type $oid" >expect &&
+	echo $object_name | git cat-file --batch-check="%(objecttype) %(objectname)" >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success "custom --batch-command format" '
-	echo "$type $sha1" >expect &&
-	echo "info $sha1" | git cat-file --batch-command="%(objecttype) %(objectname)" >actual &&
+	echo "$type $oid" >expect &&
+	echo "info $object_name" | git cat-file --batch-command="%(objecttype) %(objectname)" >actual &&
 	test_cmp expect actual
     '
 
     test_expect_success '--batch-check with %(rest)' '
 	echo "$type this is some extra content" >expect &&
-	echo "$sha1    this is some extra content" |
+	echo "$object_name    this is some extra content" |
 		git cat-file --batch-check="%(objecttype) %(rest)" >actual &&
 	test_cmp expect actual
     '
 
+    test_expect_success '--batch-check with %(objectmode)' '
+	echo "$mode $oid" >expect &&
+	echo $object_name | git cat-file --batch-check="%(objectmode) %(objectname)" >actual &&
+	test_cmp expect actual
+    '
+
     test -z "$content" ||
     test_expect_success "--batch without type ($type)" '
 	{
 		echo "$size" &&
 		echo "$content"
 	} >expect &&
-	echo $sha1 | git cat-file --batch="%(objectsize)" >actual &&
+	echo $object_name | git cat-file --batch="%(objectsize)" >actual &&
 	test_cmp expect actual
     '
 
@@ -226,7 +234,7 @@ $content"
 		echo "$type" &&
 		echo "$content"
 	} >expect &&
-	echo $sha1 | git cat-file --batch="%(objecttype)" >actual &&
+	echo $object_name | git cat-file --batch="%(objecttype)" >actual &&
 	test_cmp expect actual
     '
 }
@@ -240,7 +248,7 @@ test_expect_success "setup" '
 	git update-index --add hello
 '
 
-run_tests 'blob' $hello_sha1 $hello_size "$hello_content" "$hello_content"
+run_tests 'blob' $hello_sha1 "" $hello_size "$hello_content" "$hello_content"
 
 test_expect_success '--batch-command --buffer with flush for blob info' '
 	echo "$hello_sha1 blob $hello_size" >expect &&
@@ -270,7 +278,8 @@ tree_sha1=$(git write-tree)
 tree_size=$(($(test_oid rawsz) + 13))
 tree_pretty_content="100644 blob $hello_sha1	hello${LF}"
 
-run_tests 'tree' $tree_sha1 $tree_size "" "$tree_pretty_content"
+run_tests 'tree' $tree_sha1 "" $tree_size "" "$tree_pretty_content"
+run_tests 'blob' "$tree_sha1:hello" "100644" $hello_size "" "$hello_content"
 
 commit_message="Initial commit"
 commit_sha1=$(echo_without_newline "$commit_message" | git commit-tree $tree_sha1)
@@ -281,7 +290,7 @@ committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
 
 $commit_message"
 
-run_tests 'commit' $commit_sha1 $commit_size "$commit_content" "$commit_content"
+run_tests 'commit' $commit_sha1 "" $commit_size "$commit_content" "$commit_content"
 
 tag_header_without_timestamp="object $hello_sha1
 type blob
@@ -295,7 +304,7 @@ $tag_description"
 tag_sha1=$(echo_without_newline "$tag_content" | git hash-object -t tag --stdin -w)
 tag_size=$(strlen "$tag_content")
 
-run_tests 'tag' $tag_sha1 $tag_size "$tag_content" "$tag_content"
+run_tests 'tag' $tag_sha1 "" $tag_size "$tag_content" "$tag_content"
 
 test_expect_success "Reach a blob from a tag pointing to it" '
 	echo_without_newline "$hello_content" >expect &&
@@ -1169,6 +1178,16 @@ test_expect_success 'cat-file --batch-check respects replace objects' '
 	test_cmp expect actual
 '
 
+test_expect_success 'batch-command with a submodule' '
+	printf "160000 commit %0.*d\tsub\n" $(test_oid hexsz) 17 >tree-with-sub &&
+	tree=$(git mktree <tree-with-sub) &&
+	git cat-file --batch-check >actual <<-EOF &&
+	$tree:sub
+	EOF
+	printf "%0.*d submodule 0\n" $(test_oid hexsz) 17 >expect &&
+	test_cmp expect actual
+'
+
 # Pull the entry for object with oid "$1" out of the output of
 # "cat-file --batch", including its object content (which requires
 # parsing and reading a set amount of bytes, hence perl).