#!/bin/bash



function check_dirs()
{
  for i in $*
  do
    check_dir $i
  done
}
 
function check_dir()
{
  if [ -d $1 ]
  then
    return 0
  else
    usage "$1 is not a directory"
  fi
}

function check_permissions()
{
  if ! [ -r $1 ]
  then
    usage "You do not have read permissions on $1"
  elif ! [ -w $2 ]
  then
    usage "You do not have write permissions on $2"
  fi
  for i in `ls $1`
  do
    if ! [ -r $1$i ]
    then
      usage "You do not have read permissions on $1$i"
    fi
  done
  for i in `ls $2`
  do
    if ! [ -w $2$i ]
    then
      usage "You do not have write permissions on $2$i"
    fi
  done
}

function copy_files()
{
  for i in `ls $1`
  do
    if [ -f $1$i ]
    then
      #it is a file not a dir
      cp $1$i $2$i
    fi
  done
}  

function usage()
{
  echo Error: $1
  echo Usage: assign1 source_dir dest_dir
  exit
}

function check_args()
{
  if [ $# != 2 ]
  then
    usage "There need to be exactly two command line arguments"
  fi
}

check_args $*

check_dirs $*

check_permissions $*

copy_files $*