#!/usr/bin/env bash
usage() {
echo "Usage:"
echo " at <DATE> && command..."
}
[[ -z "$1" ]] && { echo "Error: No DATE argument provided." >&2; usage; exit 1; }
d="$(date -d "${@}" +%s)"
while [[ "$d" -ge "$(date +%s)" ]]; do
_dt=$((d - $(date +%s)))
days=$((_dt / 86400))
echo -ne "\rTime Remaining: ${days}d $(date -u --date @$((_dt)) +%H:%M:%S) ";
sleep 0.1
done