How I can export multiple objects with command line?
If I use --export-id, it exports all visible objects, so I add --export-id-only, now I get only one object.

How to export needed objects by id and hide others?

You might be able to put them into groups or layers and id those for export.

Not that I know nothing about how to use Inkscape on the command line.

Multiple objects means multiples layers/groups, so how to export only two or more objects?

So I want to create list of objects that will be exported.

My "theory" was to put 2 or more object in a group, and export the group.

Sometime I need to export multiple objects, yes I group needed objects into layer, but I need to export one object in multiple layers. So I need to duplicate this object to layers??? You never want to edit this file again So this is not a solution.

The question is how to export 2 or more objects, and it doesn't matter what it is, line, circle, layer or anything else.