#!/usr/bin/env perl

use strict;
use warnings;

use Vulcan::OptConf;

$| ++;

$Vulcan::OptConf::ARGC = -1;
@Vulcan::OptConf::CONF = qw( pass_through no_ignore_case );

=head1 SYNOPSIS

Execute a command in a loop; sleep between iterations; write command
output to a file.

$0 [--interval seconds] [--output file] command ..

=cut
my %o = Vulcan::OptConf
    ->load()->set( interval => 1 )->get( qw( interval=i output=s ) )->dump();

my $out = delete $o{output};
my $clr = 'clear';

if ( $out )
{
    my $tmp =  "$out.tmp";
    $clr = "mv $tmp $out";
    push @ARGV, '>', $tmp;
}

my $cmd = join ' ', @ARGV;

for ( my $now; $now = time; )
{
    system $clr unless $out;
    last if system $cmd;
    system $clr if $out;

    my $due = $o{interval} + $now - time;
    sleep $due if $due > 0;
}

exit $?;