update

Author: reliveyy

tools/core/image.py

@@ -142,7 +142,7 @@ def _run_command(self, cmd):
         if on_travis:
             self._run_command_on_travis(cmd)
             return
-        print("$ %s", cmd)
+        print("$ %s" % cmd)
         exit_code = os.system(cmd)
         if exit_code != 0:
             raise RuntimeError("Failed to build (exit_code=%s)" % exit_code)