[shell script]计算退伍时间

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[shell script]计算退伍时间

这是一个简单(入门级)的shell脚本，输入退伍的日期，可以计算还有几天退伍。

#!/bin/bash
#program
#   you input your demobilization date,I calculate how many days before you demobilize.
#history
#2018/8/3 15:01 wk//提示信息
echo "this program will try to calculate :"
echo "how many days before your demobilization..."
read -p "please input your demobilization date(YYYYMMDD ex>20180803):" demdate//判断输入格式是否符合要求
date_d=$( echo $demdate | grep '[0-9]\{8\}' )
if [ "$date_d" == "" ];thenecho "please input right date" exit 1
fideclare -i dem_t=$(date --date=$demdate +%s)  //退伍日期秒数
if [ "$?" !=  "0" ];thenexit 1;
fi
declare -i now_t=$(date +%s)  //当前日期秒数
declare -i total_t=$((dem_t-now_t))  //相隔秒数
declare -i day_t=$((total_t/60/60/24)) //相隔天数
declare -i hour_t=$(($(($total_t-$day_t*60*60*24))/60/60)) //一天内的小时数
if [ "$day_t" -lt "0" ];thenecho "you had been demobilization before $((-1*$day_t)) days"
elif [ "$day_t" -eq "0" ]  && [ "$hour_t" -le "0" ];thenecho "you demdate today."
elseecho "you will demobilizate after $day_t days and $hour_t hours."
fi