Lua runs on many operating systems, and as an embedded language can run just about anywhere. The os package provides functionality to interface with the underlying operating system in a uniform way.
Interfacing with the operating system
Working with time
The first function to know when working with time is os.clock. This function returns the number of seconds that have elapsed since the Lua program started running. Code tends to run pretty fast, but the following code should print out two different time stamps:
print ("Time: " .. os.clock())
for i=1,1000,1 do
-- Just spin
end
print ("Time: " .. os.clock())
Seconds is a very granular measure of time. os.date can be used to retrieve less-granular bits of time...