open my $FH, '<' , $config or die "Cannot open $config: $!\n";
my $data = <$FH>;     # removing a header line? or what?
while (my $line = <$FH>) {
    next if /^\s*#|^$/;
    print "$1\n" while $data =~ m/\{([^}]*)\}/gx ;
}
close $FH;