Following the previous notes about enabling core dump, here’s a note about changing the filename of core dump.

In Linux (since Linux 2.6 and 2.4.21)
you can change the core dump filename from the file /proc/sys/kernel/core_pattern

         %%  A single % character
         %p  PID of dumped process
         %u  real UID of dumped process
         %g  real GID of dumped process
         %s  number of signal causing dump
         %t  time of dump (seconds since 0:00h, 1 Jan 1970)
         %h  hostname (same as 'nodename' returned by uname(2))
         %e  executable filename

Linux have a default core filename pattern of “core”.
Alternatively, if /proc/sys/kernel/core_uses_pid contains a non-zero value, then the core dump file name will include a suffix .PID (process id), ex: core.PID

In FreeBSD, sysctl variable “kern.corefile” controls the filename of core dump.

Any sequence of %N in this filename template will be replaced by
the process name, %P by the processes PID, and %U by the UID.

FreeBSD have a default core filename pattern of “%N.core”

You can include path in the filename pattern both in Linux and FreeBSD.
This make it possible to put core dump file in a separated directory.