#!/bin/bash# auth: xiluhua# date: 2017-02-26 read -p "please input a username:" username[ -z $username ] && echo "a username is needed" && exit 2 if id $username &> /dev/nullthen    echo $username ‘is exist‘fi read -p "please input the passward:" passward[ -z $passward ] && echo "a passward is needed" && exit 3 useradd $usernameecho "$passward" | passwd --stdin $username &> /dev/nullecho "add $username finished"