use FileHandle;

my  @files = ("file1", "file2", "file3", "file4", "file5", "file6", "file7");

my @handles = map 
{ 
    my $fh = new FileHandle; 
    $fh->open("< $_") ? $fh : undef;
}
@files;

for $x (0..6)  
{
  my $h = $handles[$_];
  print $h "$marctags[$x][3] $tagdata[$x]";
}