A little script that enumerates all files in the current folder recursively and does something to each file

emptyfiles.sh

# replaces the contents with "$FILENAME\n======" (representing a markdown header with the filename).
find . -type f -exec sh -c 'printf "$1 \n======" > "$1"' sh {} \;

# append extension ".md"
find . -type f -exec sh -c 'mv "$1" "$1.md"' sh {} \;