When you’ve downloaded a disk image for your Raspberry Pi, you need to copy it to your SD card. You can follow the simple instructions, but if you have to do this a lot it’s easier just to have a script that does it for you.

I wrote this script for use on my MacBook Air. It takes the disk image file as a parameter, e.g.

./copytocard debian6-19-04-2012.img

NOTE: The disk devices could be different on your computer. This script could wipe out the wrong disk if the wrong device numbers are used. I’m providing the script for convenience; please ensure you check it carefully before using it on your own computer. Take a look at the simple instructions so you can check which device numbers you need.

#!/bin/bash
[[ $# -eq 0 ]] && echo "I need an image file" && exit 1
IMG=$1
echo -n "Waiting for card"
df -h | grep disk2s1
RES=$?
while [[ $RES -gt 0 ]] ;
do
  echo -n .
  sleep 1
  df -h | grep disk2s1 > /dev/null
  RES=$?
done
echo
echo "Disk found"
echo "Unmounting..."
diskutil unmount /dev/disk2s1
echo "Copying (please wait)..."
dd bs=1m if=$1 of=/dev/rdisk2
echo "Ejecting..."
diskutil eject /dev/rdisk2
echo "Done. Remove card."