When I try activate map editor, game writes "nil" and doesn't run editors mode
Is it possible to run editor with this console?

This is a LUA console and NOT the ingame console.

Its basically executing what you type after /c in the ingame console.

But it actually is possible to change the controller to editor, just not by typing /editor.

try:

game.player.set_controller({type=defines.controllers.editor})

Thank you alot! It works!

But how to close editor? :)
Executing command again dosen't close editor

Start by setting yourself to the god controller:

game.player.set_controller({type=defines.controllers.god})

Then mouse-over your body and:

game.player.set_controller({type=defines.controllers.character, character=game.player.selected})

A very non-obvious solution for me :)
Thank you for your help!

Yeah, its more of a tool for modders (and server admins).

I've lost my character's body, is there a way to find it quickly?)

Only if you know what you did to lose it.

Like if you deleted it, its gone. If you switched controllers, its still somewhere, ...

You can try to do a find entity in area and loop over everything and if its your body print its location.