Programming

mDate1='23:06:2007'
mDateA=`echo $mDate1 | sed 's/\(..\):\(..\):\(....\)/\3\2\1/'`
mDate2='22:06:2007'
mDateB=`echo $mDate2 | sed 's/\(..\):\(..\):\(....\)/\3\2\1/'`
if [ ${mDateA} -gt ${mDateB} ]; then
  ...
else
  ...
fi

#include <time.h>
/****************************
date_compar ()
parameters:
       date1 and date2 - dates to compare
       fmt - format (see man date) of the date string
       full_day - (because date + time causes intermediate value)
               0 == include seconds in differences 
               1 == do not include seconds, only compare days
returns:
     0- parameters are equal
     1- date1 is more recent
  (-1)- date2 is more recent
  
     assumes dates are valid
*********************************/
int date_compar(const char *date1, 
                const char *date2, 
                const char *fmt, 
                const int full_day)
{
	struct tm tmp;
	time_t one=0;
	time_t two=0;
	int retval=0;
	
	strptime(date1, fmt, &tmp);
	one=mktime(&tmp);
	strptime(date2, fmt, &tmp);
	two=mktime(&tmp);
	if( full_day==1)
	{
		one/=86400; /* convert seconds to days */
		two/=86400;
	}
    if (one > two)
    	retval =1;
    if(two > one)
    	retval=(-1);
    return retval;			
}

int main()
{
	char *date1="17:06:2007";
	char *date2="18:06:2007";
	char *fmt="%d:%m:%Y";
	int result=date_compar(date1, date2, fmt, 0);
	char chresult=' ';
	
	chresult=(result==0)? '=': (result > 0)? '>': '<';
	printf("%s %c %s\n", date1, chresult, date2);
	return 0;
}