Using the shell, SSH and putty, from the MineOS wiki: https://minecraft.codeemo.com/mineoswiki/index.php?title=PuTTY
PuTTY user guide: https://the.earth.li/~sgtatham/putty/0.58/htmldoc/
You use PuTTY (or an equvivalent SSH client) to connect to your servers console through the network to be able to run commands.
You use Filezilla or an equvivalent FTP client supporting secure FTP) to connect to your servers file system to transfer files.
To run commands needing elevated privileges (things needing root) you use SUDO (SuperUser DO) to run one command, or SU to connect to the root user from a normal user (if this is activated). You can also run “sudo -s” to elevate your current session to root, if root access is not activated. Root accsess is deactivated by default, since using it is a shortcut to doing irreparable damage to your system, and your minecraft servers behaves in a really weird way if you use root to manage them. The only thing you really need root for is updating MineOS or the system OS itself.
To read the logs log into the system with putty, using the default “mc” user. then run the following command:
sudo nano /var/log/mineos.log
(to exit press ctrl-x)
OR
sudo vi /var/log/mineos.log
vi and nano are two text editors in your files system.
(vi : https://www.cs.colostate.edu/helpdocs/vi.html, I do not really know vi, I always used nano)
@tNt: Using the console is really just usable if you can run driectly on the physical machine, or through the Virtual Machine session. If I understand @the_scruffy_guy correct, that installation MineOS installed through a VM, and do not have a monitor, keyboard or mouse connected. This makes a direct connection to the console impratctical. PuTTY is therefore a better choice. Another reason for using putty is that it supports hilighting text and pasting it back by rightclicking.