Catch keyboard interrupt and quit

IPython/core/application.py

@@ -201,8 +201,11 b' class BaseIPythonApplication(Application):'
             self.log.warning("Subcommand `ipython {sub}` is deprecated and will be removed "
                              "in future versions.".format(sub=subc))
             self.log.warning("You likely want to use `jupyter {sub}`... continue "
-                             "in 5 sec".format(sub=subc))
-            time.sleep(5)
+                             "in 5 sec. Press Ctrl-C to quit now.".format(sub=subc))
+            try:
+                time.sleep(5)
+            except KeyboardInterrupt:
+                sys.exit(1)
         return super(BaseIPythonApplication, self).initialize_subcommand(subc, argv)
 
     def init_crash_handler(self):