I also would like to know the Linux command to find it.
This is non-trivial, and might not be impossible without tracing cables, but the general steps (assuming an ethernet or wireless connection) you would take which may identify the router, depending on your setup are:
The MAC address of your router is the globally unique name of the Interface on the router. You need to identify which router it belongs to. The first 3 octets of A MAC address are assigned by a central body, so by copying the MAC address into http://www.coffer.com/mac_find/ it will provide the manufacturers name. Hopefully this will provide enough of a hint to tell you what router you are plugged into - otherwise you will need to do an audit to find the MAC address of the device. (The MAC address will sometimes be written on the router, and will invariably be available if you log into the router). Note that a router will typically have 1 MAC per interface, so it would be common to have multiple MAC addresses.