#!bin/bash#program:# this program shows "hello world" in your screen.#history:#2015/01/01 Richard first releasePATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/binexport PATHecho -e "hello world! \a \n"exit 0~/.bashrc 里修改aliassource ~/.bashrc 然后生效