extractFileByGI.pl

#! /usr/bin/perl
use strict;

use Bio::DB::Query::GenBank;
use Bio::DB::GenBank;

my $genBank = Bio::DB::GenBank->new(-strand => 1, -complexity => 1);

foreach my $arg (@ARGV) {
    eval {
        my $sequence = $genBank->get_Seq_by_gi($arg);
        print "Sequence ", $sequence->id, "\n";

        # Here comes the code for extracting CDS
        # subsequence and writing it down in a file.

    };
    if($@) {
        print STDERR "An unexpected error occured: ", $@, "\n";
    }
}