(for practical needs, not building blocks)
See also: https://github.com/sarnobat/unix
(e.g. using antec) From host that doesn't have ssh:
autossh -M0 -p 222 -R 9001:localhost:22 sarnobat@host.personaldomain.com
rsync:
rsync -a -v -e 'ssh -t -p 222 sarnobat@host.personaldomain.com ssh -t -p 9001 WIN+sridhar@localhost ssh -t sarnobat@jumphost.mycompany.com ssh' sarnobat@apphost.mycompany.com:/tmp/sarnobat_bashrc /tmp/test