Move all contents from a folder to another with shell script
The space character is used by bash to separate different parameters to a command so you need to protect/escape it if it occurs in filenames (or other parameters):

mv /Users/diogosaraiva/Music/Downloads\ -\ Youtube/Novas/*  /Users/diogosaraiva/Music/Downloads\ -\ Youtube/Tratadas


You can also use quotes to protect the space characters from being misinterpreted by the shell but need to move the * outside the quotes then to allow wildcard expansion:

mv "/Users/diogosaraiva/Music/Downloads - Youtube/Novas/"* "/Users/diogosaraiva/Music/Downloads - Youtube/Tratadas"