root@ubuntu2004:~# cat send_email.sh 
#!/bin/bash


email_send='18*@qq.com'
email_passwd='授权码'
email_smtp_server='smtp.qq.com'

. /etc/os-release

msg_error() {
  echo -e "\033[1;31m$1\033[0m"
}

msg_info() {
  echo -e "\033[1;32m$1\033[0m"
}

msg_warn() {
  echo -e "\033[1;33m$1\033[0m"
}


color () {
    RES_COL=60  #横向距离，不能太小
    MOVE_TO_COL="echo -en \\033[${RES_COL}G"
    SETCOLOR_SUCCESS="echo -en \\033[1;32m"
    SETCOLOR_FAILURE="echo -en \\033[1;31m"
    SETCOLOR_WARNING="echo -en \\033[1;33m"
    SETCOLOR_NORMAL="echo -en \E[0m"
    echo -n "$1" && $MOVE_TO_COL            #输出文字
    echo -n "["
    if [ $2 = "success" -o $2 = "0" ] ;then   #成功绿色，失败红色
        ${SETCOLOR_SUCCESS}
        echo -n $"  OK  "    
    elif [ $2 = "failure" -o $2 = "1"  ] ;then 
        ${SETCOLOR_FAILURE}
        echo -n $"FAILED"
    else
        ${SETCOLOR_WARNING}
        echo -n $"WARNING"
    fi
    ${SETCOLOR_NORMAL}
    echo -n "]"
    echo 
}


install_sendemail () {
    if [[ $ID =~ rhel|centos|rocky ]];then
        rpm -q sendemail &> /dev/null ||  yum install -y sendemail
    elif [ $ID = 'ubuntu' ];then
        dpkg -l sendemail &>/dev/null || { apt update; apt install -y libio-socket-ssl-perl libnet-ssleay-perl sendemail ; } 
    else
        color "不支持此操作系统，退出!" 1
        exit
    fi
}

send_email () {
    local email_receive="$1"
    local email_subject="$2"
    local email_message="$3"
    sendemail -f $email_send -t $email_receive -u $email_subject -m $email_message -s $email_smtp_server -o message-charset=utf-8 -o tls=yes -xu $email_send -xp $email_passwd
    [ $? -eq 0 ] && color "邮件发送成功!" 0 || color "邮件发送失败!" 1 
}

if [ $# -ne 3 ];then 
    color "脚本参数不正确!" 1
    msg_info "Usage: `basename $0` <mail_address> <subject> <message>"
    exit 1
fi

install_sendemail 

send_email "$1" "$2" "$3"

root@ubuntu2004:~# ./send_email.sh 81X@qq.com Winter  "Are you OK"

$# 表示提供到shell脚本或者函数的参数总数；
$1 表示第一个参数。

[root@rocky script]# cat send_email.sh 
#!/bin/bash

email_send='29308620@qq.com'
email_passwd='dgezyimkdswwbhea'
email_smtp_server='smtp.qq.com'

. /etc/os-release

msg_error() {
  echo -e "\033[1;31m$1\033[0m"
}

msg_info() {
  echo -e "\033[1;32m$1\033[0m"
}

msg_warn() {
  echo -e "\033[1;33m$1\033[0m"
}


color () {
    RES_COL=70
    MOVE_TO_COL="echo -en \\033[${RES_COL}G"
    SETCOLOR_SUCCESS="echo -en \\033[1;32m"
    SETCOLOR_FAILURE="echo -en \\033[1;31m"
    SETCOLOR_WARNING="echo -en \\033[1;33m"
    SETCOLOR_NORMAL="echo -en \E[0m"
    echo -n "$1" && $MOVE_TO_COL
    echo -n "["
    if [ $2 = "success" -o $2 = "0" ] ;then
        ${SETCOLOR_SUCCESS}
        echo -n $"  OK  "    
    elif [ $2 = "failure" -o $2 = "1"  ] ;then 
        ${SETCOLOR_FAILURE}
        echo -n $"FAILED"
    else
        ${SETCOLOR_WARNING}
        echo -n $"WARNING"
    fi
    ${SETCOLOR_NORMAL}
    echo -n "]"
    echo 
}


install_sendemail () {
    if [[ $ID =~ rhel|centos|rocky ]];then
        rpm -q sendemail &> /dev/null ||  yum install -y sendemail
    elif [ $ID = 'ubuntu' ];then
        dpkg -l sendemail &>/dev/null || { apt update; apt install -y libio-socket-ssl-perl libnet-ssleay-perl sendemail ; } 
    else
        color "不支持此操作系统，退出!" 1
        exit
    fi
}

send_email () {
    local email_receive="$1"
    local email_subject="$2"
    local email_message="$3"
    sendemail -f $email_send -t $email_receive -u $email_subject -m $email_message -s $email_smtp_server -o message-charset=utf-8 -o tls=yes -xu $email_send -xp $email_passwd
    [ $? -eq 0 ] && color "邮件发送成功!" success || color "邮件发送失败!" failure 
}

if [ $# -ne 3 ];then 
    color "脚本参数不正确!" 1
    msg_info "Usage: `basename $0` <mail_address> <subject> <message>"
    exit 1
fi

install_sendemail 

send_email "$1" "$2" "$3"