We were having a discussion about how you can do that just the other day.
Here is an example that will just output the result of that date calculation. Try it, then you should be able to use it to update your URL string.
echo $(date -v +5d "+%Y-%m-%d")
A useful command to know is man
. If you type man date
at the command prompt it will give you access to the documentation for the date
command. -v
is one of the options for this command in Z-shell and it allows you to do basic date arithmetic. man
is a fantastic starting point for whenever you are using a command line instruction or utility - all the documentation is built right in; though an Internet search can often bring up the output of man
too.