Here are some ways to add hours, days, months etc to a given date and get the result from the bash shell
To add seconds to a given date
rramads@rramads-us2:~$ date -d “2010-08-12 05:30:30 PM 15 seconds”Thu Aug 12 17:30:45 EDT 2010
To add minutes to a given date in the bash shell you can
rramads@rramads-us2:~$ date -d “2010-08-12 05:30:30 PM 15 minutes”
Thu Aug 12 17:45:30 EDT 2010
To add hours to a given date in the bash shell you can
rramads@rramads-us2:~$ date -d “2010-08-12 05:30:30 PM 15 hours”
Fri Aug 13 08:30:30 EDT 2010
To add days to a given date
rramads@rramads-us2:~$ date -d “2010-08-12 05:30:30 PM 15 days”
Fri Aug 27 17:30:30 EDT 2010
To add months to a given date
rramads@rramads-us2:~$ date -d “2010-08-12 05:30:30 PM 15 months”Sat Nov 12 17:30:30 EST 2011