How to get the operating system running PHP- How to get the OS on which PHP is running?

problem ：

For building a unix/dos specific script I need to know on which kind of operating system I am. In order to build specific unix/dos Script for , I need to know which operating system I use .

How do i get this information? How do I get this information ？
phpinfo();tells me a lot more and not very clear whether I'm running on unix or not. Tell me more and it's not clear if I'm unix Up operation .

---

Solution ：

Reference resources ： https://stackoom.com/en/question/6DbQ