$ ssh -f -L 8080:localhost:22 -o ExitOnForwardFailure=yes root@server.com "sleep 60" ; sleep 3; ps xu|grep ssh
bind: Address already in use
halfgaar     780086  0.0  0.0  51432   728 ?        Ss   12:32   0:00 ssh -f -L 8080:localhost:22 -o ExitOnForwardFailure=yes root@server.com sleep 60

halfgaar@<localmachine>: ~
$ ssh -L 8080:localhost:22 -o ExitOnForwardFailure=yes root@server.com
bind: Address already in use
Linux <remoteserver> 4.9.0-8-686-pae #1 SMP Debian 4.9.144-3 (2019-02-02) i686

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Fri May 31 12:39:27 2019 from 84.22.107.110
root@<remoteserver>: ~
#