I know the parent folder that will contain these mp3 files I am looking for, but I have allot of sub-folders in it.
How can I search for all files and sub-folders for files ending with .mp3?
You can use the
You need to put the pattern in quotes so that it does not get expanded by the shell.
As you didn't specify you need a Terminal, you can actually just use the Finder. Enter the parent folder, press Cmd-F, then hit the + button on the right.
Adjust your settings like seen below. You'll get a list of all MP3 files.