And yes, but you will have to wait until tomorrow morning, as I am in bed now *g*
lsusb lists all the USB items connected to your Pi. The command filters the output through grep, which searches for the word "hub". This gives me a count of how many logical hubs your Pi is seeing.
The second command, with -t, asks the Pi to give a tree listing of the hubs. That shows how the logical hubs are connected to each other. The output includes every USB device connected, which might show that some logical hubs are in fact empty on your system.
You can find out more about lsusb by using the man ("manual", as in instruction manual) command:
man lsusb
nice explanation
here we go:
[minepeon@minepeon ~]$ lsusb | grep hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 009: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 010: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 011: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 006: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 007: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 008: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
[minepeon@minepeon ~]$ lsusb -t
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/3p, 480M
|__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=smsc95xx, 480M
|__ Port 2: Dev 4, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 2: Dev 6, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 9, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 12, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 2: Dev 13, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 3: Dev 14, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 4: Dev 15, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 3: Dev 7, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 10, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 16, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 2: Dev 17, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 3: Dev 18, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 4: Dev 19, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 4: Dev 8, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 11, If 0, Class=Hub, Driver=hub/4p, 480M
|__ Port 1: Dev 20, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 2: Dev 21, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 3: Dev 22, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 4: Dev 23, If 0, Class=Vendor Specific Class, Driver=usbfs, 12M
|__ Port 3: Dev 5, If 0, Class=Vendor Specific Class, Driver=rtl8192cu, 480M