Script to convert filenames to lowercase depending on extension

Question

Script to convert filenames to lowercase depending on extension

Answer 1

I'm not sure how your question links to the code, so I'll focus on the question.

In bash versions 4 and above, you can do this by using something like the following:

for file in ./*.JPG; do     # Iterate over all items in the current directory that match *.JPG
    mv "$file" "${file,,}"  # Move the file found to a lowercase mapping (this is what the ,, parameter expansion method does)
done

Obviously replace *.JPG with the equivalent extension you're wanting.

Answer 2

To do it recursively for a number of extensions, you could use zsh's zmv:

zsh -c '
   autoload zmv
   ext=(jpg mp3 ogg)
   zmv -n "(**/)(*.(#i)(${(j:|:)ext}))" "\$1\${(L)2}"'

(remove -n (or replace it with -v) when happy).

Above the (#i) is to turn on case insensitive globbing, and ${(j:|:)ext} is to join the elements of the $ext list with |. You could also directly write it:

zsh -c '
   autoload zmv
   zmv -n "(**/)(*.(#i)(ogg|jpg|mp3))" "\$1\${(L)2}"'