linux 下的打印进程树的代码，两种方法，一种是基于内核模块的，一种是用proc实现的-linux printing process under the tree code, the two methods, one is based on the kernel module, and one is achieved by proc

根据"proc"目录打印进程树以及通过内核打印进程树。-According to " proc" directory tree, and the printing process printing process by the kernel tree.