convert a given YYYY-MM-DD to epoch time

[Anonymous Monk]

Can I please get some assistance with this issue. Im trying to convert given dates in the format YYYY-MM-DD ( from the inputmodfile file) to epoch seconds in order to determine what day it was. I saw that I could parse the date and using localtime and timelocal, achieve this but its not working. I'm getting the following errors from the part in red

"Use of uninitialized value in subtraction (-) at ./test3.pl line 30.
Use of uninitialized value in subtraction (-) at ./test3.pl line 31.
Month '-1' out of range 0..11 at ./test3.pl line 35"

This is the script:

#!/usr/bin/perl

use strict;
use warnings;
use Time::Local;
#use Time::gmtime;

my $inputfile = "/home/vdelaney/test.txt";
my $inputmodfile = "/home/vdelaney/test_mod.txt";
my $outputfile = "/home/vdelaney/test_out.txt";

system("cat \"$inputfile\" | awk '{print \$2}'| awk -F 'T' '{print \$1
+}' > $inputmodfile");

my $seventh_days= 7 * 24 * 60 * 60;
print " seventh_day from today=$seventh_days\n";
my ($old_day, $old_month, $old_year) = (localtime(time - $seventh_days
+))[3..5];
#print "old_day=$old_day  ,old_month= $old_month,old_year= $old_year \
+n";
my $cutoff = sprintf('%04d-%02d-%02d', 
                     $old_year + 1900, $old_month + 1, $old_day);
print "cutoff date=$cutoff\n";

open my $handle, '<', $inputmodfile;
chomp(my @lines = <$handle>);
close $handle;

#print "List of lines that have dates older than the cutoff date\n";
my ($yyyy, $mm, $dd); 
my $epoch_seconds;
my $strings;

for my $date (@lines) {

 ($yyyy, $mm, $dd) = ($date =~ /(\d+)-(\d+)-(\d+)/);
 $epoch_seconds = timelocal(0, 0, 0, $dd, $mm, $yyyy-1900);
 $strings = localtime($epoch_seconds);

 print "$date : $epoch_seconds\n" if $date lt $cutoff;
}

[ambrus]

Are you sure that this is the exact code you're running? The line numbers don't seem to match.

In any case, if it is the same code, then you never seem to handle the case when the regular expression actually matches. Maybe your input file contains lines where it doesn't match. Use an if statement around the assignment, such as

if (($yyyy, $mm, $dd) = ($date =~ /(\d+)-(\d+)-(\d+)/)) {
 $epoch_seconds = timelocal(0, 0, 0, $dd, $mm, $yyyy-1900);
 $strings = localtime($epoch_seconds);
 print "$date : $epoch_seconds\n" if $date lt $cutoff;
} else {
 # do something here when the line does not contain a date
}

You might also want to use some anchors in the regex if you want to make sure the whole line matches.

[jeffa]

Your main requirement seems to simply be to "determine what day it was," and you can do that with several CPAN modules. I really like Time::Piece

use strict;
use warnings;
use Time::Piece;

my $date = shift || '1999-12-31';
my $time = Time::Piece->strptime( $date, '%Y-%m-%d' );
print $time, $/;
print $time->fullday, $/;