【Shell】脚本日期问题

系统管理员 2022-06-11 01:41 220阅读 0赞

脚本完成输入一个日期，输出日期前一天和后一天日期

# get the date of next day
    #!/bin/bash 
    function nextday
    {
        read -p "input a correct day（YYYY mm dd）: " year month day
    
            today=$year$month$day
            if [ ${#year} -eq 0 -a ${#month} -eq 0 -a ${#day} -eq 0 ];then
                    echo "the next day is : " `date -d "+1day" +"%Y %m %d"`
                    exit
            elif [ ${#year} -ne 4 -o ${#month} -ne 2 -o ${#day} -ne 2 ];then
                    echo "Error: date format error"
                    exit
            elif [ "$today" != "$(date -d $today +%Y%m%d 2>/dev/null)" ];then
                    echo "Error: no such date"
                    exit
            fi
    
        month=`expr $month + 0`
    
        next_year=`expr $year + 0`
        next_month=`expr $month + 0`
        next_day=`expr $day + 1`
    
            case $month in
                1|3|5|7|8|10|12) max_day=31;;
                4|6|9|11)        max_day=30;;
                2)               max_day=28
                   [ `expr $year % 4`    -eq 0 ] && max_day=29
                   [ `expr $year % 100`  -eq 0 ] && max_day=28
                   [ `expr $year % 400` -eq 0 ] && max_day=29
                ;;
            esac
    
        if [ $day -eq $max_day ]
        then
            next_month=`expr $month + 1`
                    next_day=1
            [ $next_month -eq 13 ] &&  next_year=`expr $year + 1` && next_month=1 && next_day=1
        fi
    
        [ $next_month -lt 10 ] && next_month="0$next_month"
        [ $next_day   -lt 10 ] && next_day="0$next_day"
    
            tomorrow="$next_year $next_month $next_day"
    
            echo "the next day is :"$tomorrow 
    
    
        last_year=`expr $year + 0`
        last_month=`expr $month + 0`
        last_day=`expr $day - 1`
        if [ $day -eq 1 ]
        then
           last_month=`expr $month - 1`
                        last_day=$max_day
           [ $last_month -eq 0 ] && last_year=`expr $year - 1` && last_month=12 && last_day=$max_day
        fi
    
        [ $last_month -lt 10 ] && last_month="0$last_month"
        [ $last_day   -lt 10 ] && last_day="0$last_day"
    
            yesterday="$last_year $last_month $last_day"
    
            echo "the last day is :"$yesterday 
    }
    
    nextday