open( my $FH, "<", $filename )
  or die "Error: couldn't open file '$filename': $!\n";
while( 1 ) {
  while( my $line = <$FH> ) {
    print $line;
  }
  sleep 1;
  seek( $FH, 0, 1 );
} # while 1

while( 1 ) {
  while( my $line = <$FH> ) {
    print $line;
  }
  sleep 1;
  $FH->clearerr();
} # while 1