Thanks for your replies!. The problem is that I need a directory structure (which I am able to generate through the above perl script) which has sample files like .png or .doc etc. Currently I am generating directories with the above perl script and then by using touch(shell) command to create the file in there directories. The shell script to create files in there directories is given below-

#!/bin/bash

random_content () {
< /dev/urandom tr -dc A-Za-z0-9_ | head -c300
}

for I in {1..10}
do
touch file$I.txt
random_content > file$I.png
done
[download]

I am a newbie ,I need these two codes to work together. Please guide.