diff --git a/Documentation/git-show-index.txt b/Documentation/git-show-index.txt
index a8a9509e0e..424e4ba84c 100644
--- a/Documentation/git-show-index.txt
+++ b/Documentation/git-show-index.txt
@@ -14,13 +14,27 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-Read the idx file for a Git packfile created with
-'git pack-objects' command from the standard input, and
-dump its contents.
+Read the `.idx` file for a Git packfile (created with
+linkgit:git-pack-objects[1] or linkgit:git-index-pack[1]) from the
+standard input, and dump its contents. The output consists of one object
+per line, with each line containing two or three space-separated
+columns:
 
-The information it outputs is subset of what you can get from
-'git verify-pack -v'; this command only shows the packfile
-offset and SHA-1 of each object.
+  - the first column is the offset in bytes of the object within the
+    corresponding packfile
+
+  - the second column is the object id of the object
+
+  - if the index version is 2 or higher, the third column contains the
+    CRC32 of the object data
+
+The objects are output in the order in which they are found in the index
+file, which should be (in a correctly constructed file) sorted by object
+id.
+
+Note that you can get more information on a packfile by calling
+linkgit:git-verify-pack[1]. However, as this command considers only the
+index file itself, it's both faster and more flexible.
 
 GIT
 ---
diff --git a/Makefile b/Makefile
index e4b503d259..edba229552 100644
--- a/Makefile
+++ b/Makefile
@@ -689,7 +689,6 @@ PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += imap-send.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += shell.o
-PROGRAM_OBJS += show-index.o
 PROGRAM_OBJS += remote-testsvn.o
 
 # Binary suffix, set to .exe for Windows builds
@@ -1077,6 +1076,7 @@ BUILTIN_OBJS += builtin/send-pack.o
 BUILTIN_OBJS += builtin/serve.o
 BUILTIN_OBJS += builtin/shortlog.o
 BUILTIN_OBJS += builtin/show-branch.o
+BUILTIN_OBJS += builtin/show-index.o
 BUILTIN_OBJS += builtin/show-ref.o
 BUILTIN_OBJS += builtin/stripspace.o
 BUILTIN_OBJS += builtin/submodule--helper.o
diff --git a/builtin.h b/builtin.h
index 4e0f64723e..0362f1ce25 100644
--- a/builtin.h
+++ b/builtin.h
@@ -220,6 +220,7 @@ extern int cmd_serve(int argc, const char **argv, const char *prefix);
 extern int cmd_shortlog(int argc, const char **argv, const char *prefix);
 extern int cmd_show(int argc, const char **argv, const char *prefix);
 extern int cmd_show_branch(int argc, const char **argv, const char *prefix);
+extern int cmd_show_index(int argc, const char **argv, const char *prefix);
 extern int cmd_status(int argc, const char **argv, const char *prefix);
 extern int cmd_stripspace(int argc, const char **argv, const char *prefix);
 extern int cmd_submodule__helper(int argc, const char **argv, const char *prefix);
diff --git a/show-index.c b/builtin/show-index.c
similarity index 96%
rename from show-index.c
rename to builtin/show-index.c
index 1ead41e211..a6e678809e 100644
--- a/show-index.c
+++ b/builtin/show-index.c
@@ -1,10 +1,11 @@
+#include "builtin.h"
 #include "cache.h"
 #include "pack.h"
 
 static const char show_index_usage[] =
 "git show-index";
 
-int cmd_main(int argc, const char **argv)
+int cmd_show_index(int argc, const char **argv, const char *prefix)
 {
 	int i;
 	unsigned nr;
diff --git a/git.c b/git.c
index c2f48d53dd..9dbe6ffaa7 100644
--- a/git.c
+++ b/git.c
@@ -537,6 +537,7 @@ static struct cmd_struct commands[] = {
 	{ "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 	{ "show", cmd_show, RUN_SETUP },
 	{ "show-branch", cmd_show_branch, RUN_SETUP },
+	{ "show-index", cmd_show_index },
 	{ "show-ref", cmd_show_ref, RUN_SETUP },
 	{ "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },