Days difference between two dates - Shell Programming and Scripting

jim mcnamara · #2 (**permalink**) 03-10-2008

try this to start - note you have to handle cross-years eg 2007 -> 2008

Code:

#!/bin/ksh
yday()
{
        perl -e '
                use POSIX qw(strftime);
                $fmt = "%j";  # %j day of year 1 - 366
                $mday = substr("$ARGV[0]", 8, 2);
                $mon =  substr("$ARGV[0]", 5 ,2);
                $year = substr("$ARGV[0]", 0 ,4);                  
                $weekday =
                  strftime($fmt, 0, 0, 0, $mday , $mon - 1, $year - 1900, -1, -1, -1);
                print int $weekday;
                ' "$1"
}

today=$( yday 2008-03-10 )
oldat=$( yday 2008-01-03 )
ddiff=$(( $today - $oldat ))
echo "$ddiff"