my @filenames;
push @filenames, $_ while (<STDIN>);
chomp@filenames;

use Data::Dumper;
print Dumper(@filenames);

##</code><code>##

ls | my_script.pl

##</code><code>##

my %hash; # Declare your hash.

$hash{$key} = $sequence; # Assign $sequence to the hash with key $key.

my $sequence_im_looking_for = $hash{$key}; # Get the sequence by looking it up with its key $key.