#!/usr/bin/perl
use warnings;
use strict;
use POSIX();

$|=1;

END { exec $0  }  #needed to catch internal die's
my $sub = sub { exec $0 };

# POSIX unmasks the sigprocmask properly
my $sigset = POSIX::SigSet->new();
my $action = POSIX::SigAction->new( 
                     $sub, $sigset, &POSIX::SA_NODEFER );

POSIX::sigaction(&POSIX::SIGINT, $action);
POSIX::sigaction(&POSIX::SIGUSR1, $action);
POSIX::sigaction(&POSIX::SIGTERM, $action);
# can still be killed with a kill -9 or SIGKILL
# but kill -15 or SIGTERM will restart

my $counter = 0;
while(1){
   print ++$counter,"\n"; 
     if($counter == 4){die}
   sleep 1;
}


__END__