#my $ref = tie *DIAG,"File::Tail",(
#    name        => $Config->{'_'}{'DIAGFILE'},
#    interval    => 1,  # wait at start
#    maxinterval => 10, # change to suit
#    adjustafter => 10  # change to suit
#);

my $fh = File::Tail->new(
  name        => $Config->{'_'}{'DIAGFILE'},
  interval    => 1,  # wait at start
  maxinterval => 10, # change to suit
  adjustafter => 10  # change to suit
);

my $restart;
#while (my $line = <DIAG>) { 
while (my $line = $fh->read) { 
  print $line;
  if ($line =~ /is higher than 5 seconds/) {
.
.