my @files = <../data/text/*.txt>;
my @display_files = map /([^\/]+)\.txt/, @files;
Encode::from_to($_, "ISO-8859-7", "utf8") for @display_files;

print br;
print start_form( action=>'index.pl' );
    print h1( {class=>'lime'}, "&#917;&#960;&#941;&#955;&#949;&#958;&#949; &#964;&#959; &#954;&#949;&#943;&#956;&#949;&#957;&#959; &#960;&#959;&#965; &#963;&#949; &#949;&#957;&#948;&#953;&#945;&#966;&#941;&#961;&#949;&#953; => ",
                                popup_menu( -name=>'select', -values=>\@display_files ),
                                submit('&#917;&#956;&#966;&#940;&#957;&#953;&#963;&#951;'));
print end_form;

my $passage = param('select') || "&#913;&#961;&#967;&#953;&#954;&#942; &#931;&#949;&#955;&#943;&#948;&#945;!";
Encode::from_to($passage, "utf8", "ISO-8859-7") if param();


if ( param('select') )
{
    open(FILE, "<../data/text/$passage.txt") or die $!;
.....