Shell Programming and Scripting

Hello,

do any body help me to sort a file by date using perl?

thanks in advance

Esham

What do you mean by 'sort a file by date'?

(1) You have a file with its content with some dates and you want to sort them?

(2) You have a set of files and you would like to sort the list of files by date?

Hello,

I am having the first case... viz..

(1) You have a file with its content with some dates and you want to sort them?

Please help...

Regards
Esham

How to do exactly depends on what your file contains.

For instance, taking the simplest case that the file itself contains just dates but not other fields, then it is pretty straightforward (assuming the file is not extremely large):

Code:

use Date::Parse;

open FILE, "<MyDates.txt";
my @dates = <FILE>;
my @sorted_dates = sort {
    str2time($a) <=> str2time($b)
} @dates;
foreach (@sorted_dates) {
    print $_;
}

Input File:
21 Dec 2005
23 Oct 2002
8 June 2004

Output:
23 Oct 2002
8 June 2004
21 Dec 2005

If the date is a certain column of the file, you may need to do some data extraction in the sort() block. How to do depends on the structure of your file. This is just a simple example to illustrate the idea.

Code:

use Date::Parse;

open FILE, "<MyDates2.txt";
my @dates = <FILE>;
my @sorted_dates = sort {
 my ($d1, $d2) = map { /^(.+):.+$/ && $1 } ($a, $b);
    str2time($d1) <=> str2time($d2)
} @dates;
foreach (@sorted_dates) {
    print $_;
}

Input file:
21 Dec 2005:Event A
23 Oct 2002:Event B
8 June 2004:Event C

Output:
23 Oct 2002:Event B
8 June 2004:Event C
21 Dec 2005:Event A

Thanks a lot for that great reply..
Trying to learn it..what each lines does..

cheers..
esham