#!/usr/bin/perl

use strict;
use warnings;

eval {
    local $SIG{ALRM} = sub { die "alarm\n" };
    alarm 2;
    system("perl -e '1 while 1'") == 0
      or die "Cannot do infinite loop: $!";
    alarm 0;
};
die $@ unless $@ eq "alarm\n";

# the following lines let me do a 'ps awux|grep perl' 
# while this is running
print 'Hanging ...';
<STDIN>;