Group files in a directory by year

group.sh

#!/usr/bin/env bash
#
# Usage: group.sh target_directory
# Result:
#   target_directory/2020/...files from 2020
#   target_directory/2021/...files from 2021
#

set -e

target="$(cd "$(dirname "$1")"; pwd)/$(basename "$1")"

# list files only, with the year
# example:
#   2020 image.jpg
#   2021 some_filename with space.jpg
files="$(ls -l --time-style=+%Y $target | grep '^-' | tr -s ' ' | cut -d " " -f 6- | awk NF)"

while IFS= read -r line; do
    IFS=" " read year filename <<< "$line"
    dir="$target/$year"
    file="$target/$filename"

    printf "%s <- %s" $dir $file

    mkdir -p "$dir"
    mv "$file" "$dir"

    printf " $\n"
done <<< "$files"