Hey there,

I was trying out attaching usb devices to qubes and thought this might
be useful to other people.  If you have a device with a complicated
description (eg a Yubikey) it can be a pain to figure out what device ID
it's being attached to in sys-usb so you can use `qvm-usb attach` to
send it to an AppVM.  

```
[sean@dom0 ~]# qvm-usb
BACKEND:DEVID     DESCRIPTION                    USED BY
fedora-25:1-1     QEMU_QEMU_USB_Tablet_42        
p:1-1             QEMU_QEMU_USB_Tablet_42        
sys-firewall:1-1  QEMU_QEMU_USB_Tablet_42        
sys-usb:1-3       Yubico_Yubikey_4_OTP+U2F+CCID  
sys-usb:1-6       0489_e076                      
vault:1-1         QEMU_QEMU_USB_Tablet_42        
```

Typing `qvm-usb`, looking down for  where my Yubikey is, then looking
accross for the `sys-usb:1-3` next to it, then typing `qvm-usb attach
somevm sys-usb:1-3` will get pretty old pretty fast.

Luckily, unix is awesome.  I have created a couple of small shell
functions which search the output of qvm-usb on the description
and attach or detach.  Thus:


```
[sean@dom0 ~]# usb-attach somevm Yubi
[sean@dom0 ~]# qvm-usb
BACKEND:DEVID     DESCRIPTION                    USED BY
fedora-25:1-1     QEMU_QEMU_USB_Tablet_42        
p:1-1             QEMU_QEMU_USB_Tablet_42        
sys-firewall:1-1  QEMU_QEMU_USB_Tablet_42        
sys-usb:1-3       Yubico_Yubikey_4_OTP+U2F+CCID  somevm
sys-usb:1-6       0489_e076                      
vault:1-1         QEMU_QEMU_USB_Tablet_42        
```

...and likewise...

```
[sean@dom0 ~]# usb-detach somevm Yubi
````

If you like them you could put them (or something similar) in your
`~/.bashrc` in your dom0.

Here they are:

```
function usb-attach() {
	qvm-usb attach "${1}" $( qvm-usb | awk "/${2}/"'{print $1;exit}' )
}

function usb-detach() {
	qvm-usb detach "${1}" $( qvm-usb | awk "/${2}/"'{print $1;exit}' )
}

```

Cheers,

Sean