Save core dump to file named ‘core’ on Linux Ubuntu

By default crashes are processed by apport app, so first step is to disable it:

sudo systemctl stop apport
sudo systemctl disable apport

Then you have to set core file name to core and disable adding PID to core file name. Create file /etc/sysctl.d/99-crash.conf with content:

kernel.core_pattern=core
kernel.core_uses_pid=0

Then you have to reload system config:

sysctl --system