diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index fb7fc92145..1bb3a06680 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -54,6 +54,12 @@ static void show_commit(struct commit *commit)
 		fputs(header_prefix, stdout);
 	if (commit->object.flags & BOUNDARY)
 		putchar('-');
+	else if (revs.left_right) {
+		if (commit->object.flags & SYMMETRIC_LEFT)
+			putchar('<');
+		else
+			putchar('>');
+	}
 	if (revs.abbrev_commit && revs.abbrev)
 		fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
 		      stdout);
diff --git a/commit.c b/commit.c
index a6d543eee7..289ef65eb1 100644
--- a/commit.c
+++ b/commit.c
@@ -868,11 +868,11 @@ void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 
 /* merge-rebase stuff */
 
-/* bits #0..7 in revision.h */
-#define PARENT1		(1u<< 8)
-#define PARENT2		(1u<< 9)
-#define STALE		(1u<<10)
-#define RESULT		(1u<<11)
+/* bits #0..15 in revision.h */
+#define PARENT1		(1u<<16)
+#define PARENT2		(1u<<17)
+#define STALE		(1u<<18)
+#define RESULT		(1u<<19)
 
 static struct commit *interesting(struct commit_list *list)
 {
diff --git a/log-tree.c b/log-tree.c
index 8787df5cc6..35be33aaf7 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -114,6 +114,14 @@ void show_log(struct rev_info *opt, const char *sep)
 
 	opt->loginfo = NULL;
 	if (!opt->verbose_header) {
+		if (opt->left_right) {
+			if (commit->object.flags & BOUNDARY)
+				putchar('-');
+			else if (commit->object.flags & SYMMETRIC_LEFT)
+				putchar('<');
+			else
+				putchar('>');
+		}
 		fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit), stdout);
 		if (opt->parents)
 			show_parents(commit, abbrev_commit);
@@ -192,10 +200,20 @@ void show_log(struct rev_info *opt, const char *sep)
 			opt->diffopt.stat_sep = buffer;
 		}
 	} else {
-		printf("%s%s%s",
-		       diff_get_color(opt->diffopt.color_diff, DIFF_COMMIT),
-		       opt->commit_format == CMIT_FMT_ONELINE ? "" : "commit ",
-		       diff_unique_abbrev(commit->object.sha1, abbrev_commit));
+		fputs(diff_get_color(opt->diffopt.color_diff, DIFF_COMMIT),
+		      stdout);
+		if (opt->commit_format != CMIT_FMT_ONELINE)
+			fputs("commit ", stdout);
+		if (opt->left_right) {
+			if (commit->object.flags & BOUNDARY)
+				putchar('-');
+			else if (commit->object.flags & SYMMETRIC_LEFT)
+				putchar('<');
+			else
+				putchar('>');
+		}
+		fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit),
+		      stdout);
 		if (opt->parents)
 			show_parents(commit, abbrev_commit);
 		if (parent)
diff --git a/revision.c b/revision.c
index 7b6f91f83e..4dae5342eb 100644
--- a/revision.c
+++ b/revision.c
@@ -343,6 +343,7 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 {
 	struct commit_list *parent = commit->parents;
+	unsigned left_flag;
 
 	if (commit->object.flags & ADDED)
 		return;
@@ -387,6 +388,7 @@ static void add_parents_to_list(struct rev_info *revs, struct commit *commit, st
 	if (revs->no_walk)
 		return;
 
+	left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 	parent = commit->parents;
 	while (parent) {
 		struct commit *p = parent->item;
@@ -394,6 +396,7 @@ static void add_parents_to_list(struct rev_info *revs, struct commit *commit, st
 		parent = parent->next;
 
 		parse_commit(p);
+		p->object.flags |= left_flag;
 		if (p->object.flags & SEEN)
 			continue;
 		p->object.flags |= SEEN;
@@ -639,7 +642,7 @@ int handle_revision_arg(const char *arg, struct rev_info *revs,
 				add_pending_commit_list(revs, exclude,
 							flags_exclude);
 				free_commit_list(exclude);
-				a->object.flags |= flags;
+				a->object.flags |= flags | SYMMETRIC_LEFT;
 			} else
 				a->object.flags |= flags_exclude;
 			b->object.flags |= flags;
@@ -849,6 +852,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				revs->boundary = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--left-right")) {
+				revs->left_right = 1;
+				continue;
+			}
 			if (!strcmp(arg, "--objects")) {
 				revs->tag_objects = 1;
 				revs->tree_objects = 1;
diff --git a/revision.h b/revision.h
index 3adab9590a..4585463a44 100644
--- a/revision.h
+++ b/revision.h
@@ -9,6 +9,7 @@
 #define BOUNDARY	(1u<<5)
 #define BOUNDARY_SHOW	(1u<<6)
 #define ADDED		(1u<<7)	/* Parents already parsed and added? */
+#define SYMMETRIC_LEFT	(1u<<8)
 
 struct rev_info;
 struct log_info;
@@ -40,6 +41,7 @@ struct rev_info {
 			limited:1,
 			unpacked:1, /* see also ignore_packed below */
 			boundary:1,
+			left_right:1,
 			parents:1;
 
 	/* Diff flags */