AOC2019day6part1

6.sh

#!/bin/bash

set -eu
set -o pipefail

orrery=/dev/shm/orrery

cd "$(dirname "$0")"
rm -rf "$orrery"
mkdir "$orrery"

orbits=($(< "$1"))

for orbit in "${orbits[@]}"; do
  inner=${orbit%)*}
  outer=${orbit#*)}
  innerdir=$(find "$orrery" -name "$inner")
  outerdir=$(find "$orrery" -name "$outer")
  if [ -z "$innerdir" ]; then
    mkdir "$orrery/$inner"
    innerdir=$orrery/$inner
  fi

  if [ -z "$outerdir" ]; then
    mkdir "$innerdir/$outer"
  else
    mv "$outerdir" "$innerdir"/
  fi
done

( cd "$orrery" && find * -printf '%d\n' )|xargs|tr \  +|bc