Comparing file properties

mcoblentz has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I am trying to determine the age of a file by comparing its last modified time to the current time. Naturally, I have hit a wall with this one because the mtime I'm managing to extract is either a string or something in a weird array. This is probably simple but I'm beating my head on the keyboard.

The simple script I'm using is this:

#!/opt/local/bin/perl

use strict;
use warnings;
use File::stat;

# initialize

my $element;
my $filename;
my $fh;
my @files;
my $sb;
my @quake_times;
my $color; 
my $cur_time = time;
my $mtime; 
print ("current time is ", $cur_time, "\n" );


@quake_times = qw( 21600 3600);

@files = qw( markers/quake markers/volcano satellites/NORAD.tle);
my $directory = "/Users/coblem/xplanet/";

foreach $element (@files) {

    $filename = $directory . $element;
    open $fh, '<', $filename;
    #$sb = stat($fh);
    #   scalar localtime $sb->mtime;
    $mtime = (stat($fh))[9];

    print ($cur_time , " ", $mtime);
    
    if (($cur_time - $mtime) > @quake_times[1]) {
        $color = 'red';
    }
        elsif (($cur_time - $mtime) > @quake_times[0]) {
            $color = 'yellow';
        }
    else {
                $color = 'green';
        }
        print ("color is ", $color, "\n");
    
}
[download]

And the terminal results I get are:

Last login: Tue Jun 25 21:03:59 on ttys000
usxxcoblemm1:~ coblem$ cd testing
usxxcoblemm1:testing coblem$ ls
Global_24h.csv        csv_loading.pl        hello_world
Quakes            filestats.pl        hello_world.pl
change_blue_marble.pl    filestats_2.pl        volcano_script.sh
clouds_4096.sh        fire.csv
usxxcoblemm1:testing coblem$ perl filestat2_2.pl
Can't open perl script "filestat2_2.pl": No such file or directory
usxxcoblemm1:testing coblem$ perl filestats_2.pl
Scalar value @quake_times[1] better written as $quake_times[1] at file
+stats_2.pl line 36.
Scalar value @quake_times[0] better written as $quake_times[0] at file
+stats_2.pl line 39.
current time is 1372261642
Use of uninitialized value $mtime in print at filestats_2.pl line 34.
Use of uninitialized value $mtime in subtraction (-) at filestats_2.pl
+ line 36.
1372261642 color is red
Use of uninitialized value $mtime in print at filestats_2.pl line 34.
Use of uninitialized value $mtime in subtraction (-) at filestats_2.pl
+ line 36.
1372261642 color is red
Use of uninitialized value $mtime in print at filestats_2.pl line 34.
Use of uninitialized value $mtime in subtraction (-) at filestats_2.pl
+ line 36.
1372261642 color is red
usxxcoblemm1:testing coblem$
[download]

If I try it with just mapping $sb onto mtime (the lines that are commented out at 'stat', I get:

Scalar value @quake_times[1] better written as $quake_times[1] at file
+stats_2.pl line 36.
Scalar value @quake_times[0] better written as $quake_times[0] at file
+stats_2.pl line 39.
current time is 1372261739
1372261739 File::stat=ARRAY(0x7f8fc902d7b0)color is green
1372261739 File::stat=ARRAY(0x7f8fc9055238)color is green
1372261739 File::stat=ARRAY(0x7f8fc9055190)color is green
usxxcoblemm1:testing coblem$
[download]

So now I'm stumped. I have come to the monastery seeking 'enlightenment'. Help me, my brothers!

Matt

Comment on Comparing file properties Select or Download Code

Replies are listed 'Best First'.
Re: Comparing file properties by arnaud99 (Beadle) on Jun 26, 2013 at 16:19 UTC
Hi Not using File::Stat, and using the 'core' stat, may be one solution `use Modern::Perl; my @files = qw { ./adt1.pl ./adt2.pl }; my $color; my $cur_time = time; my @quake_times = qw( 21600 3600); say 'Current time: ', $cur_time; foreach my $a_filename(@files) { #stat() on the file name my $mtime = (stat($a_filename))[9]; say $a_filename, ", " , $mtime; if (($cur_time - $mtime) > $quake_times[1]) { $color = 'red'; } elsif (($cur_time - $mtime) > $quake_times[0]) { $color = 'yellow'; } else { $color = 'green'; } say ("color is ", $color, "\n"); }` [download] The code above outputs: `~/perl/ex/perlmonks: perl ./adt5.pl Current time: 1372263479 ./adt1.pl, 1372261299 color is green ./adt2.pl, 1372262161 color is green` [download] I hope this helps Arnaud	[reply] [d/l] [select]
Re: Comparing file properties by Laurent_R (Canon) on Jun 26, 2013 at 17:46 UTC
Why are you not simply using the -M -A or -C file test operators which return directly the age of the file in days (and fractions of days)? It seems that's doing exactly what you need. -M : last modification -A : last access -c : last inode change	[reply]
Re^2: Comparing file properties by mcoblentz (Scribe) on Jun 27, 2013 at 00:44 UTC
Well, that is exactly what I am looking for. -M it is! Thank you!	[reply]
Re^3: Comparing file properties by kcott (Archbishop) on Jun 27, 2013 at 08:08 UTC
The documentation for the file test operators is in perlfunc under -X, which can be a little tricky to track down unless you were specifically looking for the `-X` operator. Alternatively, from the commandline, it's a little easier (although these still all take you the the same doco): `$ perldoc -f -M $ perldoc -f -A $ perldoc -f -C $ perldoc -f -X` [download] -- Ken	[reply] [d/l] [select]