centos批量创建用户并发送邮件，（修订版）

# cat user_create.sh
echo -n "创建用户输入C,删除用户输入D！"
read name
function monitor()
{
if [ "$name" == "C" ] || [ "$name" == "c" ];then
    function_create
  elif [ "$name" == "D" ] || [ "$name" == "d" ]; then
    function_rm
  else
    echo "Input Error"
fi
}

function_create ()
{
echo -n "输入用户名（英文全拼）:"
read USER_LIST
#echo -n "输入用户邮箱："
#read MAIL_LIST
echo -n "输入授权ip地址"
read IP_LIST
#DATE=$NAME
USER_FILE=./user.txt
for USER in $USER_LIST; do
    if ! id $USER &>/dev/null; then
        PASS=$(echo $RANDOM |md5sum |cut -c -)
        useradd $USER
        echo $PASS |passwd --stdin $USER &>/dev/null
        echo "$USER   $PASS" >> $USER_FILE
        echo "$USER User create successful."
      echo -n "输入用户邮箱："
      read MAIL_LIST
      echo $MAIL_LIST
      for MAIL in $MAIL_LIST;do
          if !  $MAIL  &>/dev/null; then
              echo "USR:$USER PWD:$PASS IP:$IP_LIST" |mail -s "monitor" $MAIL
            else
              echo "邮箱错误"
          fi
      done
    else
        echo "$USER User already exists!"
    fi
done
}

#function_rm ()
#{
#echo
#}
monitor