AB   Naja atra (Chinese cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Scleroglossa; Serpentes; Colubroidea;
OC   Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=8656;
//
DR   Pfam; PF00087; toxin; 1.
DR   PRINTS; PR00282; CYTOTOXIN.
DR   ProDom; PD000206; Snake_toxin; 1.
DR   PROSITE; PS00272; SNAKE_TOXIN; 1.
KW   Venom; Cytotoxin; Cardiotoxin; Multigene family; 3D-structure; Signal.
FT   SIGNAL        1     21
FT   CHAIN        22     81       CYTOTOXIN 2.
FT   DISULFID     24     42
//

##</code><code>##

perl myprog.pl a.db

##</code><code>##

$/ = "\/\/\n";
$counter=1;
while (<>){
  # Read the entry
    print "Entry $counter\n";
    print "I don't know what to do \n";
  #do something  
    $counter++
    }       

##</code><code>##

my $infile =$ARGV[0];
open(IN, $infile) or die "Can't open input file: $!";

$/ = "\/\/\n";
$counter=1;

while (<IN>){
  # Read the entry
    print "Entry $counter\n";
    print "Hallo to you....\n";
  # do something
    $counter++
    }