Can I restart Bluetooth from the terminal? I have a rooted Galaxy S 2 (I9100) and was wondering if I can restart the Bluetooth on my phone via the terminal client on my phone.
The following terminal command should enable Bluetooth via adb shell or Terminal Emulator app:

su
am start -a android.bluetooth.adapter.action.REQUEST_ENABLE


On most versions of Android, this command will present a pop-up window to the user asking to confirm request to enable BT.  I believe this was done for security purposes whenever an app that is not system is toggling BT.

I haven't found a way to disable BT via a shell command unfortunately.

With WiFi it's a lot easier, and does not prompt user for permission:

su
svc wifi enable


will turn it on, and 

su
svc wifi disable


will turn it off.