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core_pattern

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 127 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
			``/proc/sys/fs/suid_dumpable``
	`%s`		signal number
	`%t`		UNIX time of dump
	`%h`		hostname
	`%e`		executable filename (may be shortened, could be changed by prctl etc)
	`%f`      	executable filename
	`%E`		executable path
	`%c`		maximum size of core file by resource limit RLIMIT_CORE
	`%C`		CPU the task ran on
	`%F`		pidfd number
	%<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.

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