#! /bin/bash

set -euo pipefail

FILE="$HOME/doc/notes/notes.md"

bar() {
    seq -s - 80 | sed -E 's/[0-9]+//g'
}

header() {
    printf 'untitled\n'
    bar
    date +'started: %Y-%m-%d %H:%M:%S %z'
    printf '\n\n'
}

(header && cat "$FILE") | sponge "$FILE"  # sponge is in moreutils package