go-pear.php有什么用? 它实际上做了什么?

Can anybody tell me why do we need to install a set of classes using a script ?

PHP PEAR Lib is essentially a set of classes, is it fairly good to just copy in the hosting server.

So is go-pear.bat go-pear.php is necessary or its an optional. If it is necessary would like to know why?

It is only a tool to help install PEAR classes for all users on the machine.

If you are only going to use a PEAR class in a single project, you can easily just grab the class from it's download page and bundle it with the app.