#!/bin/sh

for i in "$@"; 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
cat - | "$PROGRAM" $ARGS
echo "$PROGRAM $ARGS"