day02/sub.sh

   1 #!/bin/bash
   2
   3 filename="${1:-input.txt}"
   4
   5 exec 3<"$filename"
   6 depth=0
   7 horizontal=0
   8 aim=0
   9 aim_depth=0
  10 aim_horizontal=0
  11
  12 while read -a things -u 3; do
  13     case ${things[0]} in
  14         up)
  15             ((depth-=${things[1]}))
  16             ((aim-=${things[1]}))
  17             ;;
  18         down)
  19             ((depth+=${things[1]}))
  20             ((aim+=${things[1]}))
  21             ;;
  22         forward)
  23             ((horizontal+=${things[1]}))
  24             depth_calc=$((things[1]*aim))
  25             ((aim_depth+=$depth_calc))
  26             ((aim_horizontal+=${things[1]}))
  27             ;;
  28     esac
  29 done
  30
  31 echo "horz * depth = $((depth*$horizontal))"
  32 echo "aimed version = $((aim_depth*$aim_horizontal))"