PERL Beginners - sort function?

Author

sort function?

Radhika Sambamurti

2004-03-26, 11:14 pm

Hi,
I have written a small script that is supposed to tell me the oldest file in my directory (as per ctime). I have read the various times the various files were created, into an array called times. I have then sorted this array - @sorted_times.
when i do ls -l i get the following:

wxrwxr-x 1 radhika wheel 1028 Mar 24 11:57 chapter11_1.pl
-rwxrwxr-x 1 radhika wheel 387 Mar 24 12:37 chapter11_2.pl
-rwxrwxr-x 1 radhika wheel 551 Mar 24 21:25 chapter11_3.pl
-rwxrwxr-x 1 radhika wheel 281 Mar 15 16:28 file_basename.pl
-rw-rw-r-- 1 radhika wheel 236 Mar 21 11:46 filereader.pl
-rw-rw-r-- 1 radhika wheel 115 Mar 24 12:04 new.txt
-rw-rw-r-- 1 radhika wheel 115 Mar 24 12:00 rad.txt
-rwxrwxr-x 1 radhika wheel 648 Mar 15 15:40 rm_file_30days.pl
-rwxrwxr-x 1 radhika wheel 554 Mar 15 16:37 rmoldshares.pl

and when I execute the program I get the following:

radhika$ ./chapter11_3.pl *
Mon Mar 15 15:55:58 2004
Mon Mar 15 16:28:50 2004
Mon Mar 15 16:37:46 2004
Sun Mar 21 11:46:36 2004
Wed Mar 24 11:57:21 2004
Wed Mar 24 12:00:15 2004
Wed Mar 24 12:04:01 2004
Wed Mar 24 12:37:10 2004
Wed Mar 24 21:26:56 2004

my question is - where did the very first line from my output come from? ie Mon Mar 15 15:55:58.
As you can see, ls -l does not show any file created at that time. Even . and .. are not the above time.
Is it using sort(@array), that sorts it in some manner that I do not understand?

Thanks,
Radhika
------
I've pasted the code for the script below.
----------------------------------------
#! /usr/bin/perl -w
use strict;
use diagnostics;

my $create_time;
my $i=0;
my @times;
my @sorted_times;
my $file;

foreach $file (@ARGV) {
my($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size, $atime, $mtime, $ctime, $blksize, $blocks) = stat($file);
$create_time = localtime($ctime);
$times[$i] = $create_time;
$i++;
}
@sorted_times = sort(@times);
my $this_time;
foreach $this_time (@sorted_times) {
my($day, $mon, $dt, $tm, $yr) = split /\s+/,$this_time;
my ($hr, $mn, $sec) = split /:/, $tm;
print "$this_time\n";

}

Charles K. Clarkson

2004-03-26, 11:14 pm

Radhika Sambamurti <radhika@88thstreet.com> wrote:
:
: my question is - where did the very first line from my
: output come from? ie Mon Mar 15 15:55:58. As you can see,
: ls -l does not show any file created at that time. Even
: . and .. are not the above time.
: Is it using sort(@array), that sorts it in some manner
: that I do not understand?

Have you read perlfunc?

"The ctime field is non-portable, in particular you
cannot expect it to be a 'creation time', see Files
and Filesystems in the perlport manpage for details."

HTH,

Charles K. Clarkson
--
Mobile Homes Specialist
254 968-8328

Flemming Greve Skovengaard

2004-03-26, 11:14 pm

Use this:

__BEGIN__
use strict;
use warnings;

die "No file name supplied.\n" unless @ARGV;
my $oldest_name = shift @ARGV;
my $oldest_age = -C $oldest_name;

foreach (@ARGV) {
my $age = -C;

($oldest_name, $oldest_age) = ($_, $age) if ($age > $oldest_age);
}

printf "The oldest file is '%s', and it is %.1f days old.\n",
$oldest_name, $oldest_age;
__END__

This is a modified version of the solution to exercise 11-3 in Learning Perl
(which I assume you are reading). The unmodified version uses '-M' not '-C'.

Radhika Sambamurti wrote:
> Hi,
> I have written a small script that is supposed to tell me the oldest file in my directory (as per ctime). I have read the various times the various files were created, into an array called times. I have then sorted this array - @sorted_times.
> when i do ls -l i get the following:
>
> wxrwxr-x 1 radhika wheel 1028 Mar 24 11:57 chapter11_1.pl
> -rwxrwxr-x 1 radhika wheel 387 Mar 24 12:37 chapter11_2.pl
> -rwxrwxr-x 1 radhika wheel 551 Mar 24 21:25 chapter11_3.pl
> -rwxrwxr-x 1 radhika wheel 281 Mar 15 16:28 file_basename.pl
> -rw-rw-r-- 1 radhika wheel 236 Mar 21 11:46 filereader.pl
> -rw-rw-r-- 1 radhika wheel 115 Mar 24 12:04 new.txt
> -rw-rw-r-- 1 radhika wheel 115 Mar 24 12:00 rad.txt
> -rwxrwxr-x 1 radhika wheel 648 Mar 15 15:40 rm_file_30days.pl
> -rwxrwxr-x 1 radhika wheel 554 Mar 15 16:37 rmoldshares.pl
>
>
> and when I execute the program I get the following:
>
> radhika$ ./chapter11_3.pl *
> Mon Mar 15 15:55:58 2004
> Mon Mar 15 16:28:50 2004
> Mon Mar 15 16:37:46 2004
> Sun Mar 21 11:46:36 2004
> Wed Mar 24 11:57:21 2004
> Wed Mar 24 12:00:15 2004
> Wed Mar 24 12:04:01 2004
> Wed Mar 24 12:37:10 2004
> Wed Mar 24 21:26:56 2004
>
> my question is - where did the very first line from my output come from? ie Mon Mar 15 15:55:58.
> As you can see, ls -l does not show any file created at that time. Even . and .. are not the above time.
> Is it using sort(@array), that sorts it in some manner that I do not understand?
>
> Thanks,
> Radhika
> ------
> I've pasted the code for the script below.
> ----------------------------------------
> #! /usr/bin/perl -w
> use strict;
> use diagnostics;
>
> my $create_time;
> my $i=0;
> my @times;
> my @sorted_times;
> my $file;
>
> foreach $file (@ARGV) {
> my($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size, $atime, $mtime, $ctime, $blksize, $blocks) = stat($file);
> $create_time = localtime($ctime);
> $times[$i] = $create_time;
> $i++;
> }
> @sorted_times = sort(@times);
> my $this_time;
> foreach $this_time (@sorted_times) {
> my($day, $mon, $dt, $tm, $yr) = split /\s+/,$this_time;
> my ($hr, $mn, $sec) = split /:/, $tm;
> print "$this_time\n";
>
> }
>
>

--
Flemming Greve Skovengaard Be it the Devil or be it him
a.k.a Greven, TuxPower You can count on just one thing
<dsl58893@vip.cybercity.dk> When the time is up, you'll know
4168.08 BogoMIPS Not just one power runs the show

Bob Showalter

2004-03-26, 11:14 pm

Radhika Sambamurti wrote:
> Hi,
> I have written a small script that is supposed to tell me the oldest
> file in my directory (as per ctime). I have read the various times
> the various files were created, into an array called times. I have
> then sorted this array - @sorted_times. when i do ls -l i get the
> following:
>

[snip]

ls is showing you mtime, not ctime. You should be using mtime. ctime is
inode change time, NOT "create" time. Unix does not have a "create" time.

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