Question: I want a command to shred completely the contents of a folder/directory (which may be inside folders/directories).
Also please explain the command.

Answer: 
Shred works only on files. You need to shred the files in the dir/subdirs first and then remove the directories. try

```
find [PATH_TO_DIR] 

```

and make sure you only see the files you want to delete

```
find [PATH_TO_DIR] -exec shred -u {} \;

```

then remove the dirs with 

```
rm -rf [PATH_TO_DIR]

```
I have inserted the following bash script for this purpose in my .bashrc

```
function rm2 {

  for var in $@
  do
  if [ -d $var ]
  then
     nohup $( /usr/bin/find "$var" -type f -exec  shred -n 2 -u -z -x {} \;;/bin/rm -rf "$var" ) & 
  else
    nohup /usr/bin/shred -x -n 2 -u -z "$var" & 
  fi
done
exit
}

```