my @identifier = ("A1","B1","C1","D1"); 
my @idfeat = ("A1","B1");
my $pattern = join ( "|", @idfeat );

for my $eu ( 0 .. $#identifier ) {
    if ($identifier[$eu] =~ /$pattern/ ){
        print "$identifier[$eu], Feature\n";
        #my $sth=$dbh->prepare("INSERT INTO dd VALUES('$identifier[$eu]','Feature')");
        #$sth->execute();    
        #$sth->finish;
    } 
    else {
        print "$identifier[$eu], Bug\n";
        #my $sth=$dbh->prepare("INSERT INTO dd VALUES('$identifier[$eu]','Bug')");
        #$sth->execute();    
        #$sth->finish;
    }
}