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 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
        /proc/sys/fs/suid_dumpable
    %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.

source