#!/usr/bin/perl

use strict;
use warnings;

# Constants
my $BLANK_LINE = qr/^\s+$/;
my $KEY = qr/>([A-Z]{1})/;

# Variables
my %content;

# Take the data
for (<*.db>) {
	open(FILEDB, $_) or die "Cannot open file $_: $!\n";
 
	my $key;
	for (<FILEDB>) {
		if (/$BLANK_LINE/) {
			next;
		} elsif (/$KEY/) {
			$key = $1;
			if (not $content{$key}) {
				$content{$key} = ();
			}
		} else {
			chomp;
			push (@{$content{$key}}, $_);
		}
	}
 
	close(FILEDB);
}

# Write the new file
open(FILEDB, ">result.db") or die "Cannot open file result.db: $!\n";

for my $key (sort keys %content) {
	print FILEDB ">$key\n\n" . join(", ", @{$content{$key}}) . "\n\n";
}

close(FILEDB);