File with dates renamer. From (YYYY.MM.DD). From YYYYMMDD. To YYYY-MM-DD. Replaces _ with -

dated-files-renamer.sh

#!/bin/sh
[ $# -eq 0 ] && >&2 echo "❌ No files provided as arguments" && exit 1
NOSPACES_FILE_REGEXP="^([0-9]{4})([0-9]{2})([0-9]{2})(.*)$"
PARENTHESES_FILE_REGEXP="^\(([0-9]{4})\.([0-9]{2})\.([0-9]{2})\)(.*)$"

for filename in "$@";
do
    new_filename="$filename"
    printf "\"$filename\""
    # No spaces
    # Testing starts with 19|20 to ensure a bit more it's a year
    if echo "$filename" | egrep -q "^(19|20)"; then
        new_filename="$(echo "$new_filename" | sed -E "s/${NOSPACES_FILE_REGEXP}/\1-\2-\3\4/g")"
    fi
    # Parentheses
    new_filename="$(echo "$new_filename" | sed -E "s/${PARENTHESES_FILE_REGEXP}/\1-\2-\3\4/g")"

    # Undescores to dashes
    new_filename="$(echo "$new_filename" | tr '_' '-')"

    # Output diff
    if [ "$new_filename" == "$filename" ]; then
        echo " (no change)"
    else
        echo " -> \"$new_filename\""
        mv "$filename" "$new_filename"
    fi
done

RESERVED