MacBook-Pro-di-Emanuele:~ Emanuele$ hdiutil convert -format UDRW Macintosh HD/Utenti/Emanuele/Download/Ubuntu.iso -o Macintosh HD/Utenti/Emanuele/Documenti/ubuntu.img
hdiutil: convert: only a single input file can be specified
Usage:	hdiutil convert -format <format> -o <outfile> [options] <image>
	hdiutil convert -help