open( $l, "<file" ) || die "Error : $!";
my @lines = <$l>;
close( $l );

foreach my $line ( @lines ) {
  
  # Skipping if the line is empty or a comment
  next if ( $line =~ /^\s*$/ );
  next if ( $line =~ /^\s*#/ );
  
  my ($firstname, $lastname, $age) = split( /\s+/, $line );
  
  # then do whatever you have to
}