Linux

date
Mon Oct 12 09:28:36 EDT 2009
$ LC_TIME=fr_FR.ISO-8859-1 date
lun oct 12 09:29:21 EDT 2009

$ LC_TIME=fr_FR.ISO-8859-1 date -d "07/5/09"
dim jui  5 00:00:00 EDT 2009
$

/*
** DATE2EPOCH   F.P.Murphy Oct 16th, 2009
**
** USAGE: date2epoch [-d] [-f dateformat] datestring
**
**        -d turn on debugging
**        -f format strings per strptime(2) to match inputted date
**
** OUTPUT:  Prints number of seconds since the Epoch
**
** EXAMPLE: date2epoch -f "%a, %b %d, %Y %T %p" "Tue, Feb 19, 2008 08:00:02 PM"
**
**    NOTE: you may have to set the TZ environmental variable to account for
**          daylight savings time errors in your zonefile. For example on east
**          coast of US, you would currently set TZ to "EST,DST"
*/

#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <locale.h>


int
main(int argc,
     char* argv[])
{
   struct tm tm1, tm2;
   char buf[50];
   char format[50];
   char date[80];
   time_t t1;

   int c;
   int debug = 0;
   int errflg = 0;

   extern char *optarg;
   extern int optind, optopt;

   setlocale(LC_ALL, "");
   strcpy(format, "%m/%d/%y");        /* default format */

   while ((c = getopt(argc, argv, "df:h")) != -1) {
        switch(c) {
        case 'd':
            debug = 1;
            break;
        case 'f':
            strcpy(format, optarg);
            break;
        case 'h':
            errflg++;
            break;
        case '?':
            fprintf(stderr, "Unknown option: -%c\n", optopt);
            errflg++;
        }
   }
   if (errflg || (argc - optind != 1)) {
       fprintf(stderr, "Usage: date2epoch [-d] [-f dateformat] datestring\n");
       exit(2);
   }

   strcpy(date, argv[optind]);

   if (debug) {
       fprintf(stderr, "Format: %s\n", format);
       fprintf(stderr, "Date: %s\n", date);
   }

   if (!strptime(date, format, &tm1)) {
       fprintf(stderr, "strptime() error\n");
       exit(1);
   }
   strftime(buf, 50, "%d/%m/%y %H:%M:%S", &tm1);
   if ((t1 = mktime(&tm1)) == -1) {
       fprintf(stderr, "mktime() error\n");
       exit(1);
   }

   printf("%ld", (long) t1);

   exit(0);
}

$ ./date2epoch -f "%d/%m/%y %H:%M:%S" "18/6/09 12:00:00"
1245344400$
$ date1=$(./date2epoch -f "%d/%m/%y %H:%M:%S" "18/6/09 12:00:00")
$ echo $date1
1245344400
$ echo $TZ
EST,DST
$