Question

Returns a string or a table containing date and time,
formatted according to the given string format.

If the time argument is present,
this is the time to be formatted
(see the os.time function for a description of this value).
Otherwise, date formats the current time.

If format starts with '!',
then the date is formatted in Coordinated Universal Time.
After this optional character,
if format is *t,
then date returns a table with the following fields:
year (four digits), month (1--12), day (1--31),
hour (0--23), min (0--59), sec (0--61),
wday (weekday, Sunday is 1),
yday (day of the year),
and isdst (daylight saving flag, a boolean).

If format is not *t,
then date returns the date as a string,
formatted according to the same rules as the C function strftime.

When called without arguments,
date returns a reasonable date and time representation that depends on
the host system and on the current locale
(that is, os.date() is equivalent to os.date("%c")).