OK, so it doesn't have a display or input devices like a mouse or keyboard, but it does have it's own Linux Operating System in 256 MB NAND flash storage, 128MB RAM and I/O ports (gigabit ethernet, SATA and USB).
Since it doesn't have input devices or a display, if you want to run operating system commands then you need another computer and a way to connect and that's where Secure Shell or SSH comes in.
To send commands to the GoFlex Home with SSH, you need a client application on the remote PC. For Windows machines you can use PuTTY. For UNIX machines like Mac OS and Linux you can use the inbuilt "Terminal" application.
Update: Android now has an excellent SSH client app: JuiceSSH is full featured and works brilliantly.
I usually just link to the Open Stora wiki pages Easy Root Access but I've leaned not to rely on external sites. The guys at Open Stora do a fantastic job but apart from their time, hosting the site costs money, so there's no guarantee that it will always be there. There's a lot of very useful information on their site and well worth a look.
Update: sadly, it looks like the OpenStora website is no longer accessible.
Anyway, since most people use Windows I'll talk about PuTTY, but the process is pretty much the same using terminal or any client app.
Accessing the firmware let's you do all kinds of things you can't do otherwise but it can also be potentially data destructive so you should read my disclaimer before you start.
You can download PuTTY from here.
Note: Windows 10 now has an inbuilt SSH client - see link below for more details, but I'll keep using PuTTY.
https://www.howtogeek.com/336775/how-to-enable-and-use-windows-10s-built-in-ssh-commands/
In the Host Name (or IP Address) field enter
USERNAME_hipserv2_seagateplug_XXXX-XXXX-XXXX-XXXX@YOUR_IP_ADDRESS
Where USERNAME is the user name of an administrator account on your GoFlex Home.
XXXX-XXXX-XXXX-XXXX is your 16-digit product key which you can find on a label on the base of your GoFlex Home. You can also get it by clicking the About GoFlex Home link in the bottom left corner of the Seagateshare web page.
Make sure you use hyphens between the 4-digit blocks of the product key and underscores everywhere else.
Update: If you have reflashed with the firmware I made available for download then the "Product Code" is
AAAA-BBBB-CCCC-DDDD
YOUR_IP_ADDRESS is the IP address of your GoFlex Home on your LAN, something like 192.168.0.6 or 10.0.0.6 depending on your router.
Make sure the Connection Type radio button is set to SSH and the Port number should default to 22.
You might want to save the settings so you don't have to enter them again next time, then click Open and a connection window will pop-up and ask for your password.
Note that nothing happens as you type your password but when you hit enter it will validate and log you in.
To access the root file system and run commands you need to become root or superuser, so enter
sudo -s
It will ask for your password again and might also give you the standard warning;
You will get the message audit_log_user_command(): Connection refused but ignore that. The bash prompt changes from bash-3.2$ to bash-3.2# which means you are now superuser.
