#! /bin/sh
cmd=${1%% *}
[ "$cmd" = "$1" ] || args=${1#* }
case $cmd in
.calc)
printf "%s = " "$args"
echo "$args" | bc -l
;;
.units)
src=$(printf "%s" "$args" | sed 's/ ->.*//')
dst=$(printf "%s" "$args" | sed 's/.*-> //')
units -1 -v -- "$src" "$dst"
*)
exit 1
esac