Bash Shell脚本：输入时间，输出距离你的生日天数

#!/bin/bash#Program:# Input your birthday date and the program will calculate how many days before you birthday comes#History: # 2016/03/27 Linyimin First releasePATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/binexport PATHread -p "Input your birthday date(YYYYMMDD,ex -->20160327)" date1if [ "$(echo $date1 | grep "[0-9]\{8\}")" == ""  ];then    echo "Input error!"    exit 0fi #计算今天距1970年的时间秒数declare -i date_today=$(date +%s --date=$(date +%Y%m%d))declare -i date_input=$(date +%s --date=$date1)declare -i date_diff=$(($date_input-$date_today))if [ $date_diff -lt 0 ];then    date_diff=$(($date_today-$date_input))    declare -i days=$(($date_diff/60/60/24))    echo "Your birthday have passed $days days!"    exit 0 fi    days=$(($date_diff/60/60/24))echo "There are also $days days when your birthday comes!"exit 0