i have a script called date_add.sh written in k_shell

My shell script requirement is that it accepts a date from the user in the format YYYY-MM-DD and then it shows all the 15 days later day availaible in the current year

if date accepted from user is 2008-10-13,then the o/p sholud be
2008-10-28
2008-11-12
2008-11-27
2008-12-12
2008-12-27
-----------------------------------------------------------------------

How to put this logic in a loop? Also how to convert Epoch days into format YYYY-MM-DD

Current_day=`perl -e 'print int(time/86400);'`--------------------16145

but the below command is not working

perl -e '@d=localtime ((stat(shift))[9]); printf "%4d-%02d-%02d\n", $d[5]+1900,$d[4]+1,$d[3]' Current_day