my $train = shift or die "usage: $usage\n";
if ($train !~ /\A(?:ham|spam|rm)\z/) {
die "`$train' not recognized.\nusage: $usage\n";
}
my $train = shift or die "usage: $usage\n";
if ($train !~ /\A(?:ham|spam|rm)\z/) {
die "`$train' not recognized.\nusage: $usage\n";
}