Unix tools/Date

Example use of the System.Time library.

--
-- Implement the unix 'date' command in Haskell
--

import System.IO
import System.Time
import System.Locale
import System.Environment

main = do
    [s]  <- getArgs
    time <- getClockTime >>= toCalendarTime
    putStrLn $ formatCalendarTime defaultTimeLocale s time

Running this code:

$ ghc -O A.hs

$ ./a.out "%a %b %e %H:%M:%S %Z %Y"
Thu Dec 14 12:09:02 EST 2006

$ ./a.out "%y-%m-%d"               
06-12-14