hdiutil not finishing (UDRW) I'm trying to convert a .iso to a .img using

server:~ user$ hdiutil convert -format UDRW -o ~/Downloads/ubuntu-12.04-alternate-powerpc.dmg ~/Downloads/ubuntu-12.04-alternate-powerpc.iso 

Usage:  hdiutil convert -format &lt;format&gt; -o &lt;outfile&gt; [options] &lt;image&gt;
        hdiutil convert -help


Every time I run the command it creates the file on the desktop, then when it finishes running the file's gone. It's clear that there is an error somewhere, but I get no information.

Whats going wrong?
I think you just need to juggle the order of things:

hdiutil convert ~/whatever.img -format UDRW -o ~/destination.iso


I may be wrong, but top of my head I see that...