以备份 mysql 脚本为例，如下

#!/bin/bash
# 分隔符
str="-"

# 定义分割线函数
FenGeLine() {
	## 获取屏幕宽度
	ScreenLen=$(stty size |awk '{print $2}')

	## 标题宽度
	TitleLen=$(echo -n $1 |wc -c)
	#echo $TitleLen
	## 左右分割线长度
	LineLen=$(((${ScreenLen} - ${TitleLen})/2))        # 一半长度，标题居中。

    if [ ${LineLen} -gt 0 ];then
        #echo $LineLen
	    # 打印分割线
	    yes ${str} |sed ''''${LineLen}'''q' |tr -d "\n" && echo -n $1 && yes ${str} |sed ''''${LineLen}'''q' |tr -d "\n" && echo
    else
        echo "$1"
    fi

}

# 定义短选项和长选项
SHORT_OPTS="h"
LONG_OPTS="help,host:,user:,port:,password:,db:,backfile:,"

# 解析命令行选项
PARSED_OPTS=$(getopt -o $SHORT_OPTS -l $LONG_OPTS -- "$@")
if [[ $? -ne 0 ]]; then
  exit 1
fi

# 将解析结果设置为位置参数
eval set -- "$PARSED_OPTS"



# 处理选项
while true; do
  case "$1" in
    -h|--help)
      echo "Usage: $0 [options]"
      echo "  -h, --help      Show help"
      echo "  --host connect mysql ip address"
      echo "  --user connect mysql user"
      echo "  --port connect mysql port"
      echo "  --password connect mysql password"
      echo "  --db backup mysql database"
      echo "  --backfile backup file"
      shift
      exit 0
      ;;
    --host)
      host="$2"
      shift 2
      ;;
    --user)
      user="$2"
      shift 2
      ;;
    --port)
      port="$2"
      shift 2
      ;;
    --password)
      password="$2"
      shift 2
      ;;
    --db)
      db="$2"
      shift 2
      ;;
    --backfile)
      backfile="$2"
      shift 2
      ;;
    --)
      shift
      break
      ;;
    *)
      echo "Invalid option: $1"
      exit 1
      ;;
  esac
done
host=${host:-localhost}
user=${user:-root}
port=${port:-3306}
password=${password:-123456}
backfile=${backfile:-/opt/mysql-${db}.sql}

FenGeLine "host 默认值为 localhost"
FenGeLine "user 默认值为 root"

FenGeLine "port 默认值为 3306"
FenGeLine "password 默认值为 123456"
FenGeLine "backfile 默认值为 /opt/mysql${db}.sql}"

FenGeLine "传入的 host 为 $host"
FenGeLine "传入的 user 为 $user"
FenGeLine "传入的 port 为 $port"
FenGeLine "传入的 password 为 $password"
FenGeLine "传入的 db 为 $db"
FenGeLine "传入的 backfile 为 $backfile"

if [ -z "$db" ];then
mysqldump  -h$host -u$user -P$port -p$password -A > $backfile
else
mysqldump  -h$host -u$user -P$port -p$password -B $db > $backfile
fi