perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_CTYPE = "UTF-8",
LANG = "en_US.UTF-8"
   are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

I managed to hook up Arduino UNO to Raspberry Pi USB port and uploaded a hex file via linux command line...

This is very useful for upgrading the Arduino hex remotely via ssh/telnet...

[62207.804907] usb 1-1.3: Product: Arduino Uno
[62207.804918] usb 1-1.3: Manufacturer: Arduino (www.arduino.cc)
[62207.804929] usb 1-1.3: SerialNumber: XXXXXXXXX
[62208.004766] cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device
[62208.008799] usbcore: registered new interface driver cdc_acm
[62208.008838] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

$ avrdude -C /usr/share/arduino/hardware/tools/avrdude.conf -v -v -v -v -patmega328p -carduino -P/dev/ttyS0 -b115200 -D -Uflash:w:blink.cpp.hex:i

Using Port : /dev/ttyS0
Using Programmer : arduino
Overriding Baud Rate : 115200
AVR Part : ATMEGA328P

[snip]

avrdude done. Thank you.

$ cat /proc/cpuinfo
Hardware : BCM2708
Revision : 0003

USB Output Power

The resetable fuses protecting the USB outputs have been removed. This feature was implemented on some later revision 1.0 PCBs by replacing the fuses with links; revision 2.0 permanently implements this modification. It is now possible to reliably power the RPI from a USB hub that back feeds power, but it is important that the chosen hub cannot supply more than 2.5A under fault conditions.

$ dmesg

[  388.020831] usb 1-1.3.1: Product: ASUS EZ N Network Adapter
[  388.020844] usb 1-1.3.1: Manufacturer: Manufacturer Realtek
[  388.020857] usb 1-1.3.1: SerialNumber: 00e04c000001
[  388.029637] r8712u: DriverVersion: v7_0.20100831
[  388.029735] r8712u: register rtl8712_netdev_ops to netdev_ops
[  388.029755] r8712u: USB_SPEED_HIGH with 4 endpoints
[  388.030860] r8712u: Boot from EFUSE: Autoload OK
[  388.769196] r8712u: CustomerID = 0x0010
[  388.769225] r8712u: MAC Address from efuse = 30:85:a9:6e:1d:7e
[  388.769241] r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
[  389.738094] r8712u: 1 RCR=0x153f00e
[  389.738943] r8712u: 2 RCR=0x553f00e

$ lsmod

r8712u                165407  0

$ lsusb

Bus 001 Device 007: ID 0b05:1786 ASUSTek Computer, Inc. USB-N10 802.11n Network Adapter [Realtek RTL8188SU]

$wpa_passphrase <SSID> <passphrase>

Copy and paste the long strings into below :-

Edit the below file with your favourite editor, mine is vi

sudo vi /etc/network/interfaces
# Wifi settings with WPA PSK
auto wlan0
iface wlan0 inet dhcp
       wireless-mode managed
       wireless-essid <SSID>
       wpa-ssid <SSID>
# strings from wpa_passphrase
       wpa-psk <pass phrase strings output from above steps>
iface default inet dhcp

$ ifconfig

wlan0     Link encap:Ethernet  HWaddr 30:85:a9:6e:1d:7e
         inet addr:192.168.1.101  Bcast:192.168.1.255  Mask:255.255.255.0
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:464 errors:0 dropped:0 overruns:0 frame:0
         TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:47289 (46.1 KiB)  TX bytes:1590 (1.5 KiB)

$ iwconfig

wlan0     IEEE 802.11bgn  ESSID:"XXXXX"  Nickname:"rtl_wifi"
         Mode:Managed  Frequency:2.437 GHz  Access Point: BC:AE:C5:E7:D9:86
         Bit Rate:150 Mb/s   Sensitivity:0/0
         Retry:off   RTS thr:off   Fragment thr:off
         Power Management:off
         Link Quality=100/100  Signal level=100/100  Noise level=0/100
         Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
         Tx excessive retries:0  Invalid misc:0   Missed beacon:0

$ sudo ifdown wlan0 && sudo ifup wlan0