Multiple hooks can be specified by adding a space and another letter to debug.sethook. For example, you could subscribe to every possible event, like so:

debug.sethook(trace, "l c r", 1)

When subscribing to multiple hooks, remember the callback's second argument is nil, except for the line event. Check for nil as appropriate. The following code demonstrates how to do this:

function trace(event, line)
  local info = debug.getinfo(2)
  if info.what == "Lua" then
    print ("event: " .. event)
    print (" function: " .. info.name)
    print (" defined on: " .. info.linedefined)
    if line ~= nil then
      print (" called from: " .. line)
    end
  end
end