diff --git a/Makefile b/Makefile
index 6d92c57..eb34ed9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,10 @@
 
 #!/bin/sh
 
-build_root=`pwd`
+build_root=$(`sh pwd`)
 project=ems
-
-
-
 # os platform
 platform=ub22
-
-
-
 build_dir=$(build_root)/build
 release_dir=$(build_root)/release
 extra_dir=$(build_root)/extra