PERL String to Date (Custom format yyyymmdd to dd-mon-yyyy)

Shell Programming and Scripting
1

Hi All,

I am learning PERL for one of the projects, and in one of these scripts, I read a flat text file and print in the terminal.

The problem is, the text file has a date field. The format is yyyymmdd. I need to display this as dd-mon-yyyy.

Any ideas to do this? Thanks a lot for the help.

Regards
Guru
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Note: I wrongly tagged this as PERL DATE::MANIP. Looks like I need to download and use this. Is it not included in standard distribution. If not, I can't use it to. :frowning:

2

We can easily do that by using regular expression in Perl.

$line="20091029 Text File";
$line=~/([0-9]{4})([0-9]{2})([0-9]{2}).*/;
print "$3-$2-$1";
3 
open FH,"<date_file";
my $full_date = <FH>;
chomp($full_date);
if ( $full_date =~ /^([0-9]{4})([0-9]{2})([0-9]{2})/)
{
        print "$3-$2-$1\n";
}

consider that the date_file is having the data as
20100305 which is in yyyymmdd format.

Now the above script's print statement will print the output as
05-03-2010 which is in the dd-mm-yyyy format.

4

You can do this simply by the substitution.

use strict;
use warnings;
open FH , "<test"; # test is the file 
while(<FH>)
{
    $_=~s/([0-9]{4})([0-9]{2})([0-9]{2})/$3-$2-$1/g;
    print $_;
}
5

If the regex

means 20100205 to 05-02-2010, then it is wrong. I am looking for 05-FEB-2010.

6

For this,you can use the hash in your perl program.

%hash=("01"=>"Jan","02"=>"Feb","03"=>"Mar","04"=>"Apr","05"=>"May","06"=>"Jun","07"=>"Jul","08"=>"Aug","09"=>"Sep","10"=>"Oct","11"=>"Nov","12"=>"Dec");
$line="20090329 Text File";
$line=~/([0-9]{4})([0-9]{2})([0-9]{2}).*/;
print "$3-$hash{$2}-$1";
7 
use strict;

open FH , "<test";

my %hash=("01"=>"JAN","02"=>"FEB","03"=>"MAR","04"=>"APR","05"=>"MAY","06"=>"JUN","07"=>"JUL","08"=>"AUG","09"=>"SEP","10"=>"OCT","11"=>"NOV","12"=>"DEC");
while(<FH>)
{

     if(/([0-9]{4})([0-9]{2})([0-9]{2})/)
    {
    print $3."-".$hash{$2}."-".$1 ."\n";
    }
}
8 
 
 use strict;
use warnings;

my %hash=( 1=> "JAN",
        2=>"FEB",
        3 => "MAR",
        4 =>"APR",
        5=> "MAY",
        6 => "JUN",
        7 => "JUL",
        8 => "AUG",
        9 => "SEP",
        10 => "OCT",
        11 => "NOV",
        12 => "DEC"
    );

    my $line="20091029 Text File";
    $line=~/([0-9]{4})([0-9]{1,2})([0-9]{2}).*/;
   print "$1 -$hash{$2}- $3";
9

A simple regex won't suffice, as it won't translate the month number to it's name. Try this:

#!/usr/bin/perl

use strict;
use warnings;

use POSIX qw/strftime/;

my $date = "20100205";
if ( $date =~ /(\d{4})(\d{2})(\d{2})/ ) {
    print strftime( "%d-%b-%Y", 0, 0, 0, $3, $2, $1 - 1900 );
}

The POSIX module is part of the base distribution.

10

Thanks to, Vivek and Karthigayan, for your timely help.