$SIG{ALRM} = sub { die "TIMEOUT" };
eval {
	alarm(ON);
		open COMMAND, "$command |" or die "Can't fork: $!\n";
		$output .= $_ while (<COMMAND>);
		close COMMAND or die "Can't close pipe: $!\n";	
	alarm(OFF);
};

if ($@ =~ /TIMEOUT/)  {  # do stuff }

##</code><code>##

open COMMAND, "$command |" or die "Can't fork: $!\n";
eval {
	alarm(ON);
		$output .= $_ while (<COMMAND>);
	alarm(OFF);
};
close COMMAND;  #notice no 'or die stuff' here anymore