diff --git a/cli/src/main/java/org/onlab/onos/cli/RolesCommand.java b/cli/src/main/java/org/onlab/onos/cli/RolesCommand.java
index b81a0c2..55f59d5 100644
--- a/cli/src/main/java/org/onlab/onos/cli/RolesCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/RolesCommand.java
@@ -21,7 +21,7 @@
         description = "Lists mastership roles of nodes for each device.")
 public class RolesCommand extends AbstractShellCommand {
 
-    private static final String FMT_HDR = "%s: master=%s, standbys=%s";
+    private static final String FMT_HDR = "%s: master=%s, standbys=[ %s]";
 
     @Override
     protected void execute() {