经常在软件安装的时候遇到设置环境变量，但是一直不是很理解环境变量是什么

 

来自wiki的定义：

 

An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process.