#!/bin/sh
#
# Roll dice.  The format is the usual NdK (eg. 1d6, 2d20).  No error
# correction is done.  The dice count is optional (eg. 1d6 is the same
# as d6).  Multiple rolls per invocation is supported, just supply
# more arguments.
#
# Usage: `roll` NdK...

for d in "$@"; do
    echo $d
done | awk -F d 'BEGIN{srand()} { if ($1=="") { $1=1 } print $1"d"$2;\
for (i=1; i<=$1; i++) { print int(rand()*$2)+1; } }'