[window] set env variable

setx EC2_HOME “%APPDATA%\aws\ec2-api-tools” /M
http://www.dowdandassociates.com/blog/content/howto-set-an-environment-variable-in-windows-command-line-and-registry/
開啟環境變數
rundll32 sysdm.cpl,EditEnvironmentVariables
https://serverfault.com/questions/351129/can-the-environment-variables-tool-in-windows-be-launched-directly