running pg_dumpall as a cron job

Hi all

I am trying to run pg_dumpall as a cron job. I find that while
pg_dump has an option -f to name a file for output this is
not available for pg_dumpall. After reading the manual, my
guess is that best practice is to run pg_dump for each database.

Is there a preferred way of routinely saving all your
databases via pg_dump or pg_dumpall?

TIA

Richard A Lough