#! /bin/sh

if
  [ "$1" = "--help" -o $# -eq 0 ] #Ha "--help" az elso parameter vagy (-o) nincs parameter
then
  echo Usage: 5feladat.sh [ -atl \| -fakt ] [params] #Vajon a kotelezo parametereket [] koze irjuk? Azt hiszem igen. (sh --help alapjan)
  echo \(Get the average of all other params or the factorial of the second param, based on param1.\)
  exit 0
else

if [ $1 = "-atl" ]
then
  shift
  let sum=0
  for i in $@
  do
    let sum+=$i
  done
  let result=`expr $sum / $#`
elif [ $1 = -fakt"" ]
then
  let fakt=1
  for i in `seq $2`
  do
    let fakt=`expr $fakt \* $i`
  done
  let result=$fakt
else
  echo Not a valid parameter! \(Must be one of: -atl, -fakt.\)
  exit 1
fi
  echo $result
fi