Bash delete folder if not present in other folder

Question

imaging a folder structure like:

Peter
|- Cats
 |- Mini
 |- Maunz 
 |- Tippsi
|– Dogs
 |- Brutus
Eva
|- animals
 |- Mini
 |- Brutus

I'd like to delete all subfolders in Peter/*/ if they not present in Eva/animals/ (Maunz and Tippsi). This is what I have so far. It's working but it feels as my combination of loop and find is not the best solution:

for dir in ./Peter/*/*/
do
 dir=${dir%*/}
 if find './Eva/animals' -type d -name ${dir##*/} -exec false {} +
 then
 echo "${dir%*/} not found and deleted"
 rm -rf ${dir%*/}
 fi
done

For learning, can this code be optimized?

Answer 1

find is good for finding files and directories recursively in a filesystem tree. Based on your description and example, you probably don't need that. If you want to check that some directory foo exists directly under /some/path, it's much simpler and more efficient to use the test or [ builtin.

There are some other minor issues in the posted code:

• It's a good practice (and often necessary) to double-quote variables in command parameters. For example instead of rm -rf ${dir%*/} write rm -rf "${dir%*/}"

• Instead of writing ${dir%*/} 3 times, it would be better to store in a variable. In fact you did store the result of the first "call" in a variable, and since subsequent calls on the modified value will be the same, you could have used $dir.

• I think dir=${dir%/} is equivalent to dir=${dir%*/} but simpler.

Putting the above together, a cleaner, more efficient alternative:

#!/usr/bin/env bash
for dir in ./Peter/*/*/
do
 dir=${dir%/}
 name=${dir##*/}
 if ! [ -d "./Eva/animals/$name" ]
 then
 echo "$dir not found and deleted"
 rm -rf "$dir"
 fi
done