How do you allow core dumps on fedora

[gb spam]

> How can you permit core dumps files to be created on fedora. I had
> read previously that they were disabled by default. Can I create
> maximum limit on any core dump file. How can I only allow core dumps
> to occur in the /opt directory and not in the root file system?

as root:
   echo "kernel.core_pattern = /opt/core" >> /etc/sysctl.conf
   sysctl -p

as the user generating core files:
   ulimit -c 1000     (or whatever)

you need to run ulimit prior to running any process that would
generate a core dump, and you need to do it each time you log in, so
you should consider putting it in your profile.

once you ulimit -c in a process, you can only reduce it from that
point, so you'll need to log out and back in if you want to increase
it.