Compare timestamp from string with the current system day and turn bad status if it's less than 5 days

Question

I want to compare timestamp from string with the current system day and turn bad status if it's less than 5 days of the current system day, what I mean for example have those dates:

20150705
20150911

I'm wondering how to compare them with the current system date and to show output like that if the current system time is 11 Sep 2015:

20150705 bad
20150911 good

Answer 1

You can use string comparison for YYYYMMDD strings. date handles human readable dates with -d :

#!/bin/bash
old=20150905
new=201510017
good=20150911

before=$(date -d 'today - 5 days' +%Y%m%d)
after=$(date -d 'today + 5 days' +%Y%m%d)
echo $before - $after

for date in $old $new $good ; do
    if [[ $before < $date && $date < $after ]] ; then
        echo $date in the interval
    else
        echo $date outside of the interval
    fi
done

Answer 2

Try using convertion of the date string to unix time, eg

cur_date=$(date +"%s");
cat data_file | while read line;
do
   lineDate=$(date -d "$line" +"%s");
   diff=$(expr $cur_date - $lineDate);
   if [ "$diff" -gt 432000 ];
       then echo $line " bad";
   else
       echo $line " good";
   fi;
done

Answer 3

In Perl, you can use DateTime module to perform operations on Dates.You can easily subtract dates If you get two dates into DateTime object.

To convert earlier dates into DateTime , parse those dates using DateTime::Format::Strptime and then, subtract it from today's date.

So, overall this script will do your job:

#!/usr/bin/perl
use strict;
use warnings;
use DateTime;
use DateTime::Format::Strptime;

my @dates = ( "20150911", "20150705", "20150710" );
my $strp = DateTime::Format::Strptime->new( pattern => '%Y%m%d' ); # parse
my $today = DateTime->today; # get today's date

foreach (@dates) {
    my $mydate = $strp->parse_datetime($_);
    my $sub    = $today->subtract_datetime($mydate)->{'days'};
    if ( $sub > 5 ) {
        print "$_ bad\n";
    }
    else {
        print "$_ good\n";
    }
}

Answer 4

Time::Piece has been included in the standard Perl distribution since 5.10.0 in 2007.

#!/usr/bin/perl

use strict;
use warnings;
use 5.010;

use Time::Piece;
use Time::Seconds;

my $now = localtime;

while (<DATA>) {
  chomp;
  my $then = Time::Piece->strptime($_, '%Y%m%d');

  my $status = 'bad';
  if ($now - $then < 5 * ONE_DAY) {
    $status = 'good';
  }

  say "$_ $status";
}

__DATA__
20150705
20150911

Answer 5

You can also use Time::Local for this, which is built-in and converts arbitrary time & date values into epoch time for comparison:

#!/usr/bin/perl --
use warnings;
use strict;

# compare string dates against the current date
# and output each one with a 'bad' or 'good' label

use Time::Local;

while (<DATA>) {
    chomp;

    my $this_time = timelocal(0,0,12,                   # time (dst-compliant)
                              substr($_, -2),           # mday
                              substr($_, 4, 2) - 1,     # month
                              substr($_, 0, 4) - 1900); # year

    print "$_ ", (time() - $this_time <= (86400 * 5) ? 'good' : 'bad'), "\n";
}

__DATA__
20150705
20150911

Output:

$ perl script.pl 
20150705 bad
20150911 good
$ 

Note however that this solution wouldn't be 100% with the time. In other words, it relies on five 24-hour periods of time, rather than five actual calendar days.

Answer 6

Try:

#!/bin/bash

TODAY=`date +%s`
FIVE_DAYS=$((5 * 24 * 60 * 60))

for d in '20150705' '20150911'; do
    t=`date -d $d +%s`
    seconds=$((TODAY - t))
    [ $seconds -gt $FIVE_DAYS ] && result=bad || result=good
    echo "$d $result"
done