Perl Get File Last Modified Date Time No Module - perl

Question

I'm creating a script where I need to get the Last Modified Date of the files
I checked this thread How do I get a file's last modified time in Perl?
So I used the script below to get the last modified, at first it was working but when I try to run it again, the timestamp returns 00:00 January 1, 1970.
Why is that happening and how can I get the correct last modified date and time?
my $dir = '/tmp';
opendir(DIR, $dir) or die $!;
#content=readdir(DIR);
foreach(#content)
{
next unless ($_ =~ m/\bfile.txt|file2.csv\b/);
my $epoch_timestamp = (stat($_))[9];
my $timestamp = localtime($epoch_timestamp);
$f_detail = $_ .' '.$timestamp;
print "$f_detail\n";
}
closedir(DIR);
exit 0;
When I tried to run the perl, I will get this result
file.txt Thu Jan 1 00:00:00 1970
file2.csv Thu Jan 1 00:00:00 1970
Ok, last update, it is working now, I try to run all of the scripts you've given to me, standalone script. I found what's causing the default time, see the script below, I remove that in my program and it works, didn't notice this at first, sorry. But still, it feels weird because I was sure that it is working when I first run it, but now it is working so yeah thank you guys!
if (($month = ((localtime)[4] + 1)) < 10)
{
$month = '0' . $month;
}
if (($day = ((localtime)[3])) < 10)
{
$day = '0' . $day;
}
if (($year = ((localtime)[5]+1900)) >= 2000)
{
if (($year = $year - 2000) < 10)
{
$year = '0' . $year;
}
}
else
{
$year = $year - 1900;
}
$date = $month . $day . $year;

Answer 1

readdir returns file names without the full path. You need to prepend the path manually:
for (#content) {
next unless /^(?:file\.txt|file2\.csv)\z/;
my $epoch_timestamp = (stat("$dir/$_"))[9];
# ~~~~~~~~~
Also note how I changed the regex to match the file names.

Answer 2

If you have a directory name, and you want to see if some files whose names you already know exist in that directory, there's really no need for opendir/readdir - that's more helpful if you don't know the filenames ahead of time. When you do, you can just build a path using both parts and use file test operators/stat/etc. on it.
#!/usr/bin/env perl
use strict;
use warnings;
use feature qw/say/;
my $dir = '/tmp';
my #files = qw/file.txt file2.csv/;
for my $file (#files) {
# Better to use File::Spec->catfile($dir, $file), but your question
# title said no modules...
my $name = "$dir/$file";
if (-e $name) { # Does the file exist?
# _ to re-use the results of the above file test operator's stat call
my $epoch_timestamp = (stat _)[9];
my $timestamp = localtime $epoch_timestamp;
say "$file $timestamp";
}
}
Example execution:
$ perl demo.pl
file.txt Tue Feb 8 07:26:07 2022
file2.csv Tue Feb 8 07:26:10 2022

Answer 3

Following demo code utilizes glob to obtain modification time for specified files in a directory.
use strict;
use warnings;
use feature 'say';
my $dir = '/tmp';
my #files = qw(file.txt file2.csv);
my $mask = join ' ', map { "$dir/$_" } #files;
say "$_\t" . localtime((stat($_))[9]) for glob($mask);