diff --git a/nemu/src/monitor/sdb/sdb.c b/nemu/src/monitor/sdb/sdb.c
index b2f7341..d1b57c7 100644
--- a/nemu/src/monitor/sdb/sdb.c
+++ b/nemu/src/monitor/sdb/sdb.c
@@ -17,6 +17,7 @@
 #include <cpu/cpu.h>
 #include <readline/readline.h>
 #include <readline/history.h>
+#include <getopt.h>
 #include "sdb.h"
 
 static int is_batch_mode = false;
@@ -53,6 +54,11 @@ static int cmd_q(char *args) {
   return -1;
 }
 
+static int cmd_si(char *args) {
+  printf("%s", args);
+  return 0;
+}
+
 static int cmd_help(char *args);
 
 static struct {
@@ -63,6 +69,7 @@ static struct {
   { "help", "Display information about all supported commands", cmd_help },
   { "c", "Continue the execution of the program", cmd_c },
   { "q", "Exit NEMU", cmd_q },
+  { "si", "Single step [n] step", cmd_si },
 
   /* TODO: Add more commands */