flatten-pics.sh

#!/bin/bash

SRC=~/Pictures
DST=~/Pictures-flat

# 1. Recursively finds all files ending in .jpg, .jpeg, .cr2 and .png in the
#   $SRC directory (extension search is case-insensitive)
#
# 2. Gets each file's date created and creates a YYYY-MM-DD directory in the
#    $DST directory
#
# 3. Copies the file into it's $DST/YYYY-MM-DD directory, preserving it's
#    original created / modified dates and not overwriting existing files

while IFS= read -r -u3 -d $'\0' filename; do

  # get the date created
  fdate=$(stat -t %Y-%m-%d "$filename" | awk '{print $12}' | sed s/\"//g);
  d="$DST/$fdate"

  # create a date created directory
  if [ ! -d "$d" ]; then
    mkdir -v "$d"
  fi

  # copy
  # -n do not overwrite existing file
  # -p preserve created / modified dates
  # -v verbose
  cp -npv "$filename" "$d";

done 3< <(find $SRC -type f \( -iname '*.jpg' -o -iname '*jpeg' -o -iname '*.cr2' -o -iname '*.png' \) -print0)