Examples without using ssh-agent  
In all cases (with or without ssh-agent) the public key of your **initial user** should be declared in authorized_key of the **final host**

	ssh -i /home/vplesnila/data/sshkeys/id_rsa -J root@192.168.0.8 root@coruscant
	scp -i /home/vplesnila/data/sshkeys/id_rsa -J root@192.168.0.8 scripts/wireguard_stop root@coruscant:/tmp