i would like to see a command to copy an entire hash table.
i know it wouldn't benefit a lot of people, and it's easy to write such a script. but still maybe in a future version it could be implemented just for performance reasons.
until then here is the script i use right now to do the job if someone's interested.

alias hcopy {
  if ($1 == -s) {
    tokenize 32 $2-
    var %s = $true
  if (!$hget($1)) {
    echo -s * /hcopy: no such table $+(',$1,')
  if ($hget($2)) hfree $2
  hmake $2 $hget($1).size
  var %items = $hget($1,0).item, %item = 1, %it
  while (%item <= %items) {
    var %it = $hget($1,%item).item
    hadd $2 %it $hget($1,%it)
    inc %item
  if (%s) echo -s * Hashtable $+(',$1,') copied to $+(',$2,')