How can one recursively rename directories without sed or rename?

I am trying to rename a few directories that contain "Fever" to contain "Malaria" instead. The instruction is to do it without sed or rename. So far, my errors include mostly lines like mv: cannot stat ‘retest\nretest/Section-01\nretest/Section-02\nretest/Section-03\nretest/Section-04’: No such file or directory.

The best my code have done is rename directories in the first level.

Here's my directory structure:

Fever-A/Malaria-A-A

Fever-B/Fever-B-A

Fever-B/Fever-B-B

Fever-C/Malaria-A

Fever-C/Fever-C-A

Fever-C/Fever-C-B

Fever-C/Fever-C-C-C

Fever-D/Malaria-A

Fever-D/Malaria-B

The code I have so far is :

#!/bin/bash # Access directory #cd $1 # Find all subdirectories in $1 and load up array all=($(find $1 -type d)) #echo ${all[@]} # Loop through directories above for dir in ${all[@]} do # echo "$dir" cd $dir # List files with "Section" in name subdir=(:"Section*") # A second loop for directories in each dir with "Section*" for item in ${subdir[@]} do echo $item echo "--------------------" # Rename operation mv $item ${item//Fever/Malaria} done cd $1 done 

Another approach I've considered is using a function like so, but it's not working either:

#!/bin/bash rename(){ old_names=($(find $1 -maxdepth 1 -type d)) for item in ${old_names[@]} do if [[ $item = *Section* ]]; then new_name=${item//Fever/Malaria} mv $item $new_name elif [[ $1 != $item ]]; then rename $item fi rename $1 done } rename $1