Spiffy calculation on the command line!

spiffy.sh

#!/bin/bash

spiffy_calc() {
  local -a FIRST_ARG
  local -a ACC
  for var in "$@"; do
    if [[ ${var} == "in" ]]; then
      FIRST_ARG=("${ACC[@]}")
      ACC=()
    else
      ACC[${#ACC[@]}]="${var}"
    fi
  done
  if [[ ${#FIRST_ARG[@]} -gt 0 ]]; then
    gunits -t "${FIRST_ARG[*]}" "${ACC[*]}"
  else
    calc="${ACC[@]//p/+}";
    calc="${calc//x/*}";
    bc -l <<<"scale=5;$calc";
  fi
}

=() {
  spiffy_calc "${@}"
}