topic Re: perl ..with date in Operating System - Linux

perl ..with date

Abdul khadeer_1 — Thu, 05 Oct 2006 11:55:41 GMT

Hi All,(ladies and gentlemen :))
i need help in writing the perl script which checks whether a directory exists or not and read the files in a directory and sort the files according to the date they are created
Thanks in Advance

Re: perl ..with date

Peter Nikitka — Thu, 05 Oct 2006 12:23:33 GMT

Hi,

- creation date is of no means at a UNIX like system and not recorded anyway
- why perl?
- for modification time you can use in a shell something like this, to get the latest m-time first:

d=/path/to/dir
[ -d $d ] && ls -t $d

mfG Peter

Re: perl ..with date

Abdul khadeer_1 — Thu, 05 Oct 2006 13:21:53 GMT

it is requirement in my perl program.

Re: perl ..with date

spex — Thu, 05 Oct 2006 13:34:46 GMT

Hi Abdul,

#!/usr/contrib/bin/perl
$dir="/path/to/dir/";
if (-d $dir)
{
system("ls -1t $dir");
}

;-)

PCS

Re: perl ..with date

H.Merijn Brand (procura — Thu, 05 Oct 2006 13:52:28 GMT

my @files = -d $dir ? sort { -C $a <=> -C $b } glob "$dir/*" : ();

Like that?

BTW You didn't specify
- if you wanted to sort ascending or descending
- if the directory should be descended in
- if files starting with a "." should be included

Alternate way, descending and reversing the sort:

use File::Find;
my @files;
find(sub{-f&&push@files,$File::Find::name},$dir);
@files = sort { -C $b <=> -C $a } @files;

Enjoy, Have FUN! H.Merijn

Re: perl ..with date

Abdul khadeer_1 — Thu, 05 Oct 2006 13:55:19 GMT

by calling system we are calling unix utility .what if i have the same code in windows :)

Re: perl ..with date

H.Merijn Brand (procura — Thu, 05 Oct 2006 14:31:48 GMT

Then my examples will still work.

Enjoy, Have FUN! H.Merijn

Re: perl ..with date

Abdul khadeer_1 — Thu, 05 Oct 2006 15:12:48 GMT

i want sort according to the time it is modified

Re: perl ..with date

H.Merijn Brand (procura — Thu, 05 Oct 2006 15:48:48 GMT

Well, you said *Change time* in the original question.

For modification time sorting, just use -M

Sort, newest last:

my@files=sort{-M$b<=>-M$a}glob"dir/*"';

Enjoy, Have FUN! H.Merijn

Re: perl ..with date

Abdul khadeer_1 — Thu, 05 Oct 2006 15:56:50 GMT

for newest first the tag would be

Re: perl ..with date

H.Merijn Brand (procura — Thu, 05 Oct 2006 16:47:11 GMT

my@files=sort{-M$a<=>-M$b}glob"dir/*"';

(swap $a and $b in the sort)

see

# perldoc -f sort

Enjoy, Have FUN! H.Merijn [ don't forget to rate the answers ]

Re: perl ..with date

Ralph Grothe — Fri, 06 Oct 2006 07:43:50 GMT

Though it could hardly be solved much terser than what Procura gave you,
I think the terseness has a few drawbacks.
First afaik Perl is using the csh globbing mechanism when either or glob() is called.
This means that if you have many, or long named files (caveat long paths) in the directory your script may be susceptible to exhaust the No. of chars limited by the OS (e.g. getconf ARG_MAX).
Besides the single asteriks would not expand the "hidden" dot files.
To include them as well (without also catching the current and parent dir) you would have to use some arcane shell globbing pattern like such if you want to stick with glob() (or cast it through a Perl grep()).

$ perl -e 'printf"%d files in /tmp\n",scalar@{[glob"/tmp/* /tmp/.[!.]*"]}'
290 files in /tmp

For large amounts of files or long paths you are probably better off with additional opendir(), readdir(), closedir().
If you need to recurse into subdirs as well combine those in a Find::File callback.

Re: perl ..with date

H.Merijn Brand (procura — Fri, 06 Oct 2006 07:46:56 GMT

Ralph's answer is completely correct, which is why I included a File::Find example earlier in this thread.

Enjoy, Have FUN! H.Merijn

Re: perl ..with date

Abdul khadeer_1 — Fri, 06 Oct 2006 08:23:46 GMT

thanks all of you ,for helping me out