#!/usr/bin/bash
trap 'kill $(jobs -p)' EXIT
DIR=$1
MAX=$2
concat(){
cat $DIR/$file >> $DIR/$new_file
cat $DIR/$file/$file/$file >> $DIR/$new_file
}
while /bin/true ; do
file=$((RANDOM % MAX))
new_file=$((RANDOM % MAX))
concat 2> /dev/null
done