file: /proc/sys/kernel/core_pattern
variable: kernel.core_pattern
Official reference

core_pattern is used to specify a core dumpfile pattern name.

  • max length 128 characters; default value is “core”
  • core_pattern is used as a pattern template for the output filename; certain string patterns (beginning with ‘%’) are substituted with their actual values.
  • backward compatibility with core_uses_pid: If core_pattern does not include “%p” (default does not) and core_uses_pid is set, then .PID will be appended to the filename.
  • corename format specifiers:
      %<NUL>	'%' is dropped
      %%	output one '%'
      %p	pid
      %P	global pid (init PID namespace)
      %i	tid
      %I	global tid (init PID namespace)
      %u	uid (in initial user namespace)
      %g	gid (in initial user namespace)
      %d	dump mode, matches PR_SET_DUMPABLE and
      %s	signal number
      %t	UNIX time of dump
      %h	hostname
      %e	executable filename (may be shortened)
      %E	executable path
      %<OTHER> both are dropped
  • If the first character of the pattern is a ‘|’, the kernel will treat the rest of the pattern as a command to run. The core dump will be written to the standard input of that program instead of to a file.