Safely Testing A Permanently Deletion Script

How do you safely test a script that's purpose is to remove files forever? I started by not calling shred at all and replaced it with echo and ls this only took me so far. I needed to test the real thing and this is where Docker stepped in. Running a test container is so easy:

docker run -it --rm -v /project/path/recursive-shred/:/tmp/project ubuntu:xenial bash

Docker allows complete separation so even if you accidentally start shredding / all that will be lost is the container and they are disposable.

I also added a condition that protects the user from themselves by preventing the shredding of / In the same way that rm wont delete /

Generating Test Data

I needed files and directories to test the script on and I quickly grew tired of manually running mkdir and touch so used bash expansion to quickly generate a whole tree structure:

mkdir -p /tmp/data/{alpha/{alpha/,bravo/,charlie/},bravo/{,bravo/,charlie/},charlie/{alpha/,bravo/,charlie/}}
touch /tmp/data/{{1000..1100},alpha/{{a..d}{g..k}{l..p},alpha/{a..z},bravo/{a..z},charlie/{a..d}{g..k}{l..p}},bravo/{,bravo/,charlie/},charlie/{{1100..1110},alpha/{2550..2590},bravo/,charlie/{a..d}{g..k}{l..p}}}

Approach

I started with find to get the files and embedded it in a simple for loop:

for file in $(find "$directory" -type f); do
    echo "shredding $file"
done

While this worked I quickly remembered that what I really should do is just pipe finds output into xargs:

find "$directory" -type f -print | xargs -I {} echo "shredding {}"