Groups images in a directory into directories by resolution

group_by_resolution.sh

#!/bin/sh
# Groups images in a directory into directories by resolution

if [ $# -lt 1 ]; then
  echo "Usage: $0 SOURCE_DIRECTORY [TARGET_DIRECTORY]" >&2
  exit 1
fi

SOURCE_DIRECTORY="$1"
TARGET_DIRECTORY="$2"

if [ ! -d "${SOURCE_DIRECTORY}" ]; then
  echo "${SOURCE_DIRECTORY} needs to be a directory containing images." >&2
  exit 1
fi

if [ ! -d "${TARGET_DIRECTORY}" ]; then
  TARGET_DIRECTORY="${SOURCE_DIRECTORY}"
  echo "Using ${SOURCE_DIRECTORY} as the target directory."
fi

for file in "${SOURCE_DIRECTORY}"/*; do
  resolution=$(identify -format '%G' "${file}" 2>&1)
  if [ $? -ne 0 ]; then
    continue
  fi

  echo "${file}:\t${resolution}"
  mkdir -p "${TARGET_DIRECTORY}/${resolution}"
  mv "${file}" "${TARGET_DIRECTORY}/${resolution}"
done