Protein sequence:STARTXXXXX
Protein Sequence: XXXXXXXXX
Protein sequence: XXXXXXEND

##</code><code>##

use warnings;
my %database;
my $protein_id       = "";
my $line             = "";
my $datbase_filename = "";
my $start            = ">DDB";
my $end = "";

#input1: open the file containg the protein sequences.
print "Please enter the path to the fasta file of protein sequences\n";
#put the file name into $filenam
$database_filename = <STDIN>;
chomp($database_filename);    #remove newline

#open the file containing protein sequences in fasta format
open(MYFILE1, "<$database_filename")
  or die "Unable to open $database_filename: $!\n";

while (<MYFILE1>) {
    chomp;                    #remove newline
    $line = $_;
    print "Line i: $_\n";     #test
    if (($line =~ m/^>DDB/) and ($line =~ m/to\s\d+$/)) {
        $protein_id = $line;
        print "protein ID: $protein_id\n";    #test
    } else {
        # associating the protein sequence in my %proteins to its ID
        $proteins{$protein_id} = $line;
        print "sequence: $line\n";            #test
    }
}
exit;