diff --git a/vtysh/vtysh.h b/vtysh/vtysh.h
index b632b6d..e0c3a5b 100644
--- a/vtysh/vtysh.h
+++ b/vtysh/vtysh.h
@@ -51,8 +51,8 @@
 void vtysh_readline_init ();
 void vtysh_user_init ();
 
-void vtysh_execute (char *);
-void vtysh_execute_no_pager (char *);
+void vtysh_execute (const char *);
+void vtysh_execute_no_pager (const char *);
 
 char *vtysh_prompt ();