File: gawk.info,  Node: Getlocaltime Function,  Next: Readfile Function,  Prev: Join Function,  Up: General Functions

10.2.7 Managing the Time of Day
-------------------------------

The 'systime()' and 'strftime()' functions described in *note Time
Functions:: provide the minimum functionality necessary for dealing with
the time of day in human-readable form.  Although 'strftime()' is
extensive, the control formats are not necessarily easy to remember or
intuitively obvious when reading a program.

   The following function, 'getlocaltime()', populates a user-supplied
array with preformatted time information.  It returns a string with the
current time formatted in the same way as the 'date' utility:

     # getlocaltime.awk --- get the time of day in a usable format

     # Returns a string in the format of output of date(1)
     # Populates the array argument time with individual values:
     #    time["second"]       -- seconds (0 - 59)
     #    time["minute"]       -- minutes (0 - 59)
     #    time["hour"]         -- hours (0 - 23)
     #    time["althour"]      -- hours (0 - 12)
     #    time["monthday"]     -- day of month (1 - 31)
     #    time["month"]        -- month of year (1 - 12)
     #    time["monthname"]    -- name of the month
     #    time["shortmonth"]   -- short name of the month
     #    time["year"]         -- year modulo 100 (0 - 99)
     #    time["fullyear"]     -- full year
     #    time["weekday"]      -- day of week (Sunday = 0)
     #    time["altweekday"]   -- day of week (Monday = 0)
     #    time["dayname"]      -- name of weekday
     #    time["shortdayname"] -- short name of weekday
     #    time["yearday"]      -- day of year (0 - 365)
     #    time["timezone"]     -- abbreviation of timezone name
     #    time["ampm"]         -- AM or PM designation
     #    time["weeknum"]      -- week number, Sunday first day
     #    time["altweeknum"]   -- week number, Monday first day

     function getlocaltime(time,    ret, now, i)
     {
         # get time once, avoids unnecessary system calls
         now = systime()

         # return date(1)-style output
         ret = strftime("%a %b %e %H:%M:%S %Z %Y", now)

         # clear out target array
         delete time

         # fill in values, force numeric values to be
         # numeric by adding 0
         time["second"]       = strftime("%S", now) + 0
         time["minute"]       = strftime("%M", now) + 0
         time["hour"]         = strftime("%H", now) + 0
         time["althour"]      = strftime("%I", now) + 0
         time["monthday"]     = strftime("%d", now) + 0
         time["month"]        = strftime("%m", now) + 0
         time["monthname"]    = strftime("%B", now)
         time["shortmonth"]   = strftime("%b", now)
         time["year"]         = strftime("%y", now) + 0
         time["fullyear"]     = strftime("%Y", now) + 0
         time["weekday"]      = strftime("%w", now) + 0
         time["altweekday"]   = strftime("%u", now) + 0
         time["dayname"]      = strftime("%A", now)
         time["shortdayname"] = strftime("%a", now)
         time["yearday"]      = strftime("%j", now) + 0
         time["timezone"]     = strftime("%Z", now)
         time["ampm"]         = strftime("%p", now)
         time["weeknum"]      = strftime("%U", now) + 0
         time["altweeknum"]   = strftime("%W", now) + 0

         return ret
     }

   The string indices are easier to use and read than the various
formats required by 'strftime()'.  The 'alarm' program presented in
*note Alarm Program:: uses this function.  A more general design for the
'getlocaltime()' function would have allowed the user to supply an
optional timestamp value to use instead of the current time.