For backward compatibility, if /proc/sys/ kernel /core_pattern does not include "%p" and /proc/sys/ kernel /core_uses_pid (see below) is non-zero, then .PID will be appended to the core filename. ###>For backward compatibility, if /proc/sys/ kernel /core_pattern does not include "%p" and /proc/sys/ kernel /core_uses_pid (see below) is non-zero, then .PID will be appended to the core filename.