convert date into unix timestamp

For conversion of a date format into UNIX timestamp in your Perl program, you can use the mktime() function. However, you must include "use POSIX;" at the top of your script.

  Many of the parameters that mktime takes are relative(e.g. month is zero relative, year is 1900 relative) and so I would advise you to check out the unix man page for mktime. Attaching info from the man page for mktime too for your reference.  

  The Perl code snippet I used to test it out is appended below..


#!/usr/local/bin/perl
use POSIX;

#replace the parameters with your own values..
$sec = 1;
$min = 0;
$hour = 0;
$mday = 14;
$mon = 3 - 1;
$year = 2001 - 1900;
$wday = 3;
$timestamp = mktime($sec,$min,$hour,$mday,$mon,$year,$wday,0,-1);
print ($timestamp);
print("\n");

# just to get the current timestamp.
print(time());

###########################

NAME
     mktime - converts a tm structure to a calendar time

SYNOPSIS
     #include <time.h>

     time_t mktime(struct tm *timeptr);

DESCRIPTION
     The mktime() function converts the time represented  by  the
     tm  structure  pointed  to  by  timeptr into a calendar time
     (the number of seconds since 00:00:00 UTC, January 1, 1970).

     The tm structure contains the following members:

      int  tm_sec;     /* seconds after the minute [0, 61]  */
     int  tm_min;     /* minutes after the hour [0, 59] */
     int  tm_hour;    /* hour since midnight [0, 23] */
     int  tm_mday;    /* day of the month [1, 31] */
     int  tm_mon;     /* months since January [0, 11] */
     int  tm_year;    /* years since 1900 */
     int  tm_wday;    /* days since Sunday [0, 6] */
     int  tm_yday;    /* days since January 1 [0, 365] */
     int  tm_isdst;   /* flag for daylight savings time */

     In addition to computing the calendar time, mktime() normal-
     izes  the  supplied tm structure. The original values of the
     tm_wday and tm_yday components of the structure are ignored,
     and the original values of the other components are not res-
     tricted to the ranges indicated in  the  definition  of  the
     structure.  On  successful  completion,  the  values  of the
     tm_wday and tm_yday components are  set  appropriately,  and
     the  other  components  are  set  to represent the specified
     calendar time, but with their values forced to be within the
     appropriate  ranges.  The  final value of tm_mday is not set
     until tm_mon and tm_year are determined.

     The tm_year member must be for year 1901 or later.  Calendar
     times  before  20:45:52  UTC,  December  31,  1901  or after
     03:14:07 UTC,  January 19, 2038 cannot be represented. Port-
     able  applications  should  not  try  to create dates before
     00:00:00 UTC, January 1, 1970 or after 00:00:00 UTC, January
     1, 2038.

     The original values of the components may be either  greater
     than  or  less  than  the  specified  range.  For example, a
     tm_hour of -1 means 1 hour before  midnight,  tm_mday  of  0
     means  the day preceding the current month, and tm_mon of -2
     means 2 months before January of tm_year.

     If tm_isdst is positive, the original values are assumed  to
     be  in  the  alternate  timezone.  If  it turns out that the



SunOS 5.7           Last change: 17 Sep 1997                    1






C Library Functions                                    mktime(3C)



     alternate timezone is not valid for  the  computed  calendar
     time, then the components are adjusted to the main timezone.
     Likewise, if tm_isdst  is  zero,  the  original  values  are
     assumed  to be in the main timezone and are converted to the
     alternate timezone if the main timezone  is  not  valid.  If
     tm_isdst is negative, mktime() attempts to determine whether
     the alternate timezone is in effect for the specified time.

     Local timezone information is used as if mktime() had called
     tzset(). See ctime(3C).

RETURN VALUES
     The mktime() function returns the specified  calendar  time.
     If  the  calendar  time  cannot be represented, the function
     returns the value (time_t)-1.

USAGE
     The  mktime() function is MT-Safe in multithreaded  applica-
     tions, as long as no user-defined function directly modifies
     one of the following variables: timezone, altzone, daylight,
     and tzname. See ctime(3C).

EXAMPLES
     Example 1: Sample code using mktime().

     What day of the week is July 4, 2001?

     #include <stdio.h>
     #include <time.h>
     static char *const wday[] = {
             "Sunday", "Monday", "Tuesday", "Wednesday",
             "Thursday", "Friday", "Saturday", "-unknown-"
     };
     struct tm time_str;
     /*...*/
     time_str.tm_year    = 2001 - 1900;
     time_str.tm_mon = 7 - 1;
     time_str.tm_mday = 4;
     time_str.tm_hour = 0;
     time_str.tm_min = 0;
     time_str.tm_sec = 1;
     time_str.tm_isdst = -1;
     if (mktime(&time_str)== -1)
             time_str.tm_wday=7;
     printf("%s\n", wday[time_str.tm_wday]);