foreach $file(readdir DH) {
    $name = $file;
    next if $name =~ /^\./; # skip over dot files
    &addheader($_);
}

##</code><code>##

sub addheader {
    open FH, "< $indir/$file" or printf "can't open %s\n",$file;
    $line = <FH>;

    $_ = $line;

##</code><code>##

$field1 = m/^Clock/; # Check for Clock at beginning of file

printf "\n$file";
if ( $field1 == "1"){

##</code><code>##

my @lines =  <FH1>;

foreach $line ( @lines )
{
    print FH2 $line;
}