I want to do rsync only for the difference in the last 30 days. How do I specify the "30 days" on the command line below?

>rsync -avz prj# /rsource /destination


Thanks for help

from what I understand,
"rsync -avz prj# /rsource /destination" performs
the update of the differences. If this is so,
why not just run this from cron every 30 days?

Thanks for your cron job suggestion, rwb1959. I just wonder if this is just a one time job, what I should do? How do I specify the number of days, weeks, or months?

First thing you want to do is check out the
man page for the command crontab(1) and the
file format for crontab(5).
You need to edit the user's (say Joe) crontab by:

crontab -u joe -e

...the make your entry. By the way, the editor
will be either "vi" or whatever you EDITOR
env. variable is set to. The man page for the
file format should show you exactly how to make
an entry to get what you want (I don't want to
give it away ) and you save it.

just an example:

# run at 10 pm on weekdays, annoy Joe
0 22 * * 1-5 mail -s "It's 10pm" joe%Joe,%%HI JOE!!!%

Thanks for your great help ! Besides cronjob can you do a script and put the time range somewhere on the command line?