my @sorted_files
  = map {$_->[0]}
    sort {$b->[1] <=> $a->[1] or $a->[0] cmp $b->[0]}
    map {[$_, -s]} @files;

##</code><code>##

my @sorted_files = sort {-s $b <=> -s $a or $a cmp $b} @files;

##</code><code>##

sorted_files = files.sort_by {|f| [- test(?s, f), f]};