my ($date_stamp,$event,$alert_id,$status);
my $str = '2001/03/12 time>Event [21]Alert Completed (34562), Status: [22] Alert Completed,MN_netware-support';

($date_stamp,$event,$alert_id,$status) = 
   $str =~ /^([\d\/]+).*?(Event.*?ed) \((\d+)\), (.*)$/;

print "[$date_stamp]\n";
print "[$event]\n";
print "[$alert_id]\n";
print "[$status]\n";

##</code><code>##

[2001/03/12]
[Event [21]Alert Completed]
[34562]
[Status: [22] Alert Completed,MN_netware-support]

##</code><code>##

^             start at the beginning of the line
([\d\/]+)     match and save a bunch of digits and /'s
.*?           lazily match and ignore stuff until...
(Event.*?ed)  match and save of 'Event...ed'
              match but ignore the following space
\(            match a literal paren
(\d+)         match and save a bunch of digits
\),           match and ignore literal paren, comma, and space
(.*)          match and save anything until...
$             the end of the string