cronでスケジュールされたジョブの日付と時刻の時系列リストを取得します。

あなたはこれを使うことができます真珠スクリプト：

#!/usr/bin/perl
# Base on http://search.cpan.org/~pkent/Schedule-Cron-Events-1.8/cron_event_predict.plx
# initial release 20091001

use warnings;
use strict;

use Schedule::Cron::Events;
use Getopt::Std;
use Time::Local;
use vars qw($opt_f $opt_h $opt_p);
getopts('p:f:h');

if ($opt_h) { usage(); }
my $filename = shift || usage();

my $future = 2;
if (defined $opt_f) { $future = $opt_f; }
my $past = 0;
if (defined $opt_p) { $past = $opt_p; }

open (IN, "<$filename") || die "Unable to open '$filename' for read: $!";
while(<IN>) {
    my $obj = new Schedule::Cron::Events($_) || next;
    chomp;
    print "# Original line: $_\n";

    if ($future) {
        for (1..$future) {
                my $date = localtime( timelocal($obj->nextEvent) );
                print "$date - predicted future event\n";
        }
    }
    $obj->resetCounter;
    if ($past) {
        for (1..$past) {
                my $date = localtime( timelocal($obj->previousEvent) );
                print "$date - predicted past event\n";
        }
    }
    print "\n";
}
close IN;


sub usage {
    print qq{
SYNOPSIS

$0 [ -h ] [ -f number ] [ -p number ] <crontab-filename>

Reads the crontab specified and iterates over every line in it, predicting when 
each cron event in the crontab will run. Defaults to predicting the next 2 events.

    -h - show this help
    -f - how many events predited in the future. Default is 2
    -p - how many events predicted for the past. Default is 0.

EXAMPLE

$0 -f 2 -p 2 ~/my.crontab

\$Revision\$

};
    exit;
}

=pod

=head1 NAME

cron_event_predict - Reads a crontab file and predicts when event will/would have run

=head1 SYNOPSIS

cron_event_predict.plx [ -h ] [ -f number ] [ -p number ] <crontab-filename>

=head1 DESCRIPTION

A simple utility program mainly written to provide a worked example of how to use the module,
but also of some use in understanding complex or unfamiliar crontab files.

Reads the crontab specified and iterates over every line in it, predicting when 
each cron event in the crontab will run. Defaults to predicting the next 2 events.

These are the command line arguments:

    -h - show this help
    -f - how many events predited in the future. Default is 2
    -p - how many events predicted for the past. Default is 0.

Here's an example, showing the default of the next 2 predicted occurences of the each cron job:

    dev~/src/cronevent > ./cron_event_predict.plx ~/bin/crontab
    # Original line: 1-56/5 * * * * /usr/local/mrtg-2/bin/mrtg /home/admin/mrtg/mrtg.cfg
    Thu Sep 26 00:41:00 2002 - predicted future event
    Thu Sep 26 00:46:00 2002 - predicted future event

    # Original line: 34 */2 * * * /home/analog/analogwrap.bash > /dev/null
    Thu Sep 26 02:34:00 2002 - predicted future event
    Thu Sep 26 04:34:00 2002 - predicted future event

    # Original line: 38 18 * * * /home/admin/bin/allpodscript.bash > /dev/null
    Thu Sep 26 18:38:00 2002 - predicted future event
    Fri Sep 27 18:38:00 2002 - predicted future event

And here's an example showing past events too:

    dev~/src/cronevent > ./cron_event_predict.plx -f 1 -p 3 ~/bin/crontab
    # Original line: 1-56/5 * * * * /usr/local/mrtg-2/bin/mrtg /home/admin/mrtg/mrtg.cfg
    Thu Sep 26 00:41:00 2002 - predicted future event
    Thu Sep 26 00:36:00 2002 - predicted past event
    Thu Sep 26 00:31:00 2002 - predicted past event
    Thu Sep 26 00:26:00 2002 - predicted past event

    # Original line: 34 */2 * * * /home/analog/analogwrap.bash > /dev/null
    Thu Sep 26 02:34:00 2002 - predicted future event
    Thu Sep 26 00:34:00 2002 - predicted past event
    Wed Sep 25 22:34:00 2002 - predicted past event
    Wed Sep 25 20:34:00 2002 - predicted past event

    # Original line: 38 18 * * * /home/admin/bin/allpodscript.bash > /dev/null
    Thu Sep 26 18:38:00 2002 - predicted future event
    Wed Sep 25 18:38:00 2002 - predicted past event
    Tue Sep 24 18:38:00 2002 - predicted past event
    Mon Sep 23 18:38:00 2002 - predicted past event

=cut

サンプル出力：

# Original line: 03 05 * * *    /bin/bash command1
Thu Dec 25 05:03:00 2014 - predicted future event
Fri Dec 26 05:03:00 2014 - predicted future event

# Original line: 10 06 * * * size=$(du -h ~/.xsession-errors); [[ $size =~ ^[O-9]+G ]] && :> ~/.xsession-errors 
Thu Dec 25 06:10:00 2014 - predicted future event
Fri Dec 26 06:10:00 2014 - predicted future event

# Original line: 21 06 * * 1 perl WWW::Monitor.pl
Mon Dec 29 06:21:00 2014 - predicted future event
Mon Jan  5 06:21:00 2015 - predicted future event