#!/bin/sh
mkdir myroot
cd myroot
dir_lst=`echo "1 2 3 4"`
for d in ${dir_lst}; do
    mkdir dir_${d}
done
touch ./dir_1/file1
touch ./dir_2/file2
ln -s ./dir_2/file2 ./dir_3/file3
mkdir ./dir_4/pool
cd ./dir_4/pool
ln -s ../pool loop