#!/bin/sh

for i; do
  case $i in
    "-a") BITS="y"
      continue
      ;;
    *)
      ARGS="$i"
      ;;
  esac
  if [ -n "$BITS" ]; then
    case "$i" in
      256|512)
        PROGRAM="sha${i}sum"
        ;;
    esac
    unset BITS
  fi
done
"$PROGRAM" ${ARGS:+"$ARGS"}