Save configuration without LUCI

I use my own "microsystem" without LUCI. Is there any other way how to save/load settings? As far as i believe it is a complete folder /etc to be packed into tar.gz file? Is there any direct line text command over SSH terminal?

tar is my choice and sysupgrade will use its "rules" to selectively backup as well

$ sysupgrade
Usage: /sbin/sysupgrade [<upgrade-option>...] <image file or URL>
       /sbin/sysupgrade [-q] [-i] <backup-command> <file>

	-f <config>  restore configuration from .tar.gz (file or url)
	-i           interactive mode
	-c           attempt to preserve all changed files in /etc/
	-n           do not save configuration over reflash
	-p           do not attempt to restore the partition table after flash.
	-T | --test
	             Verify image and config .tar.gz but do not actually flash.
	-F | --force
	             Flash image even if image checks fail, this is dangerous!
	-q           less verbose
	-v           more verbose
	-h | --help  display this help

	-b | --create-backup <file>
	             create .tar.gz of files specified in sysupgrade.conf
	             then exit. Does not flash an image. If file is '-',
	             i.e. stdout, verbosity is set to 0 (i.e. quiet).
	-r | --restore-backup <file>
	             restore a .tar.gz created with sysupgrade -b
	             then exit. Does not flash an image. If file is '-',
	             the archive is read from stdin.
	-l | --list-backup
	             list the files that would be backed up when calling
	             sysupgrade -b. Does not create a backup file.

Jeff, thanx!

sysupgrade -b /tmp/config.tar.gz
should make a magic?

tar.gz is compulsory or /tmp/config is enough?

Personally, I use tar so I get everything if I've made a mistake with /etc/sysupgrade.conf as well as being explicit on the extension so that "helpful" OSes know that yes, I really do want to open that with tar.