find_prints.lua

-- save reference to original function
local local_print = print

-- replace with our custom function
print = function(...)
	-- print stacktrace
	local_print(debug.traceback())
	-- call original function
	local_print(...)
end

print("test")

This will monkey patch a Lua script so that you can find where the prints are. Useful if you have commented may prints out too. You can easily make a pprint() variant as well.