my $openfile = '';
foreach my $file (@file) {
   my $filename =  $file->{filename};
   my $content = $file->{content};
   if ($filename ne $openfile) {
      $openfile = $filename;
      open(FILE, "> $filename")
         or die "Can't open $filename $!";
   }
   print FILE $content;
}
close(FILE) if $openfile;

##</code><code>##

for my $file (sort {$a->{filename} cmp $b->{filename}} @files) {
 ...
}

##</code><code>##

foreach my $file (@files) {
   my $filename ...
   my $content ...
   if (!$fh{filename}) {
       open $fh{filename}, "> $filename"
          or die ...
   }
   print {$fh{filename}} $content;
}
foreach my $fh (keys %fh) {
   close($fh{$fh});
}