README.md in cumo-0.1.1 vs README.md in cumo-0.1.2

@@ -188,11 +188,11 @@
 ### Build in parallel
 
 Use `MAKEFLAGS` environment variable to specify `make` command options. You can build in parallel as:
 
 ```
-bundle exec MAKEFLAG=-j8 rake compile
+bundle exec env MAKEFLAG=-j8 rake compile
 ```
 
 ### Specify nvcc --generate-code options
 
 ```
@@ -238,9 +238,26 @@
 
 ### Run program always synchronizing CPU and GPU
 
 ```
 bundle exec CUDA_LAUNCH_BLOCKING=1
+```
+
+### Disable Cumo warnings
+
+As default, cumo shows some warnings once for each.
+
+It is possible to disable by followings:
+
+```
+export CUMO_SHOW_WARNING=OFF
+```
+
+You may want to show warnings everytime rather than once:
+
+```
+export CUMO_SHOW_WARNING=ON
+export CUMO_WARNING_ONCE=OFF
 ```
 
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/sonots/cumo.