download_flashair.sh

#!/bin/bash
URL="http://flashair"

list () {
  curl --silent "${URL}/command.cgi?op=100&DIR=${1}" \
    | awk 'BEGIN { FS=","; OFS="/" } /.+,.+,[^0,]/ { print $1,$2 }'
}

files () {
  for dir in $@; do
    list "$dir"
  done
}

directories () {
  curl --silent "${URL}/command.cgi?op=100&DIR=DCIM" \
    | awk 'BEGIN { FS=","; OFS="/" } /.+,0,/ { print $1,$2 }'
}

download () {
  i="1"
  for file in $@; do
    echo -n "[$((i++))/$#] $file: "
    mkdir -p "./$(dirname $file)"
    curl --silent --continue-at - -o "./${file}" "${URL}/${file}"
    if [[ $err -eq 0 ]]; then
      echo "OK"
    elif [[ $err -eq 52 ]]; then
      echo "OK (already downloaded)"
    else
      echo "FAIL"
    fi
  done
}

download $(files $(directories))