#!/bin/bash

#接受一个参数：

#add: 添加用户user1..user10

#del: 删除用户user1..user10

#其它：退出

#定义变量

ADD=add

DEL=del

#判断参数输入是否正确

if [ $# -ne 1 ]; then

  echo "Usage:./shell.sh add|del."

  exit 1

#输入add，添加用户

elif [ $1 = $ADD ]; then

  for I in {1..10}; do

    if ! id "user$I" &> /dev/null; then

      useradd -M "user$I"

      echo "add user$I OK."

    else

      echo "user$I exist.There's no need to newadd."

    fi

  done

#输入del，删除用户

elif [ $1 = $DEL ]; then

  for I in {1..10}; do

    if id "user$I" &> /dev/null; then

      userdel -r "user$I"

      echo "del user sucessfully."

    else

      echo "user$I not exist,no need to delete."

    fi

  done

else

  echo "tip:./shell.sh add|del."

fi