It's not at all clear how to simply read Apple 2 images or copy files from said images. It seems like starting diskm8, mounting an image, and typing cat would do something useful, but I get just this:
Disk has 2MG Magic
Block count 1600
mount disk in slot 0
dsk:0:stuff.2mg:> cat
dsk:0:stuff.2mg:>
Similarly, the copy command also does nothing:
dsk:0:stuff.2mg:> copy * /home/joe/apple2/d1
dsk:0:stuff.2mg:>
From within diskm8's command line, that's all I can do. From a bash command line, I can do just this:
diskm8 -dir * -disk stuff.2mg
This gives me a directory listing, but I cannot access or copy any of these files.