diff --git a/Documentation/git-merge-base.txt b/Documentation/git-merge-base.txt
index d1d56f194a..6099be2add 100644
--- a/Documentation/git-merge-base.txt
+++ b/Documentation/git-merge-base.txt
@@ -8,16 +8,26 @@ git-merge-base - Finds as good a common ancestor as possible for a merge
 
 SYNOPSIS
 --------
-'git-merge-base' <commit> <commit>
+'git-merge-base' [--all] <commit> <commit>
 
 DESCRIPTION
 -----------
-"git-merge-base" finds as good a common ancestor as possible. Given a
-selection of equally good common ancestors it should not be relied on
-to decide in any particular way.
+
+"git-merge-base" finds as good a common ancestor as possible between
+the two commits. That is, given two commits A and B 'git-merge-base A
+B' will output a commit which is reachable from both A and B through
+the parent relationship.
+
+Given a selection of equally good common ancestors it should not be
+relied on to decide in any particular way.
 
 The "git-merge-base" algorithm is still in flux - use the source...
 
+OPTIONS
+-------
+--all::
+	Output all common ancestors for the two commits instead of
+	just one.
 
 Author
 ------
diff --git a/Makefile b/Makefile
index 55d193780f..daa3fcea18 100644
--- a/Makefile
+++ b/Makefile
@@ -124,7 +124,7 @@ SCRIPT_SH = \
 	git-tag.sh git-verify-tag.sh \
 	git-applymbox.sh git-applypatch.sh git-am.sh \
 	git-merge.sh git-merge-stupid.sh git-merge-octopus.sh \
-	git-merge-resolve.sh git-merge-ours.sh git-grep.sh \
+	git-merge-resolve.sh git-merge-ours.sh \
 	git-lost-found.sh
 
 SCRIPT_PERL = \
@@ -169,7 +169,8 @@ PROGRAMS = \
 	git-describe$X git-merge-tree$X git-blame$X git-imap-send$X
 
 BUILT_INS = git-log$X git-whatchanged$X git-show$X \
-	git-count-objects$X git-diff$X git-push$X
+	git-count-objects$X git-diff$X git-push$X \
+	git-grep$X
 
 # what 'all' will build and 'install' will install, in gitexecdir
 ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS)
diff --git a/git-grep.sh b/git-grep.sh
deleted file mode 100755
index ad4f2fe810..0000000000
--- a/git-grep.sh
+++ /dev/null
@@ -1,62 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) Linus Torvalds, 2005
-#
-
-USAGE='[<option>...] [-e] <pattern> [<path>...]'
-SUBDIRECTORY_OK='Yes'
-. git-sh-setup
-
-got_pattern () {
-	if [ -z "$no_more_patterns" ]
-	then
-		pattern="$1" no_more_patterns=yes
-	else
-		die "git-grep: do not specify more than one pattern"
-	fi
-}
-
-no_more_patterns=
-pattern=
-flags=()
-git_flags=()
-while : ; do
-	case "$1" in
-	-o|--cached|--deleted|--others|--killed|\
-	--ignored|--modified|--exclude=*|\
-	--exclude-from=*|\--exclude-per-directory=*)
-		git_flags=("${git_flags[@]}" "$1")
-		;;
-	-e)
-		got_pattern "$2"
-		shift
-		;;
-	-A|-B|-C|-D|-d|-f|-m)
-		flags=("${flags[@]}" "$1" "$2")
-		shift
-		;;
-	--)
-		# The rest are git-ls-files paths
-		shift
-		break
-		;;
-	-*)
-		flags=("${flags[@]}" "$1")
-		;;
-	*)
-		if [ -z "$no_more_patterns" ]
-		then
-			got_pattern "$1"
-			shift
-		fi
-		[ "$1" = -- ] && shift
-		break
-		;;
-	esac
-	shift
-done
-[ "$pattern" ] || {
-	usage
-}
-git-ls-files -z "${git_flags[@]}" -- "$@" |
-	xargs -0 grep "${flags[@]}" -e "$pattern" --
diff --git a/merge-base.c b/merge-base.c
index f0dc06ef55..4856ca01c3 100644
--- a/merge-base.c
+++ b/merge-base.c
@@ -82,8 +82,9 @@ static struct commit *interesting(struct commit_list *list)
  * commit B.
  *
  *
- * Another pathological example how this thing can fail to mark an ancestor
- * of a merge base as UNINTERESTING without the postprocessing phase.
+ * Another pathological example how this thing used to fail to mark an
+ * ancestor of a merge base as UNINTERESTING before we introduced the
+ * postprocessing phase (mark_reachable_commits).
  *
  *		  2
  *		  H
@@ -118,7 +119,9 @@ static struct commit *interesting(struct commit_list *list)
  *	 D7			2 3 7 7 3 2 1 2
  *	 E7			2 3 7 7 7 2 1 2
  *
- * and we end up showing E as an interesting merge base.
+ * and we ended up showing E as an interesting merge base.
+ * The postprocessing phase re-injects C and continues traversal
+ * to contaminate D and E.
  */
 
 static int show_all = 0;