You've used the ray command so far simply without any command option. Actually ray has around 80 command options that you can insert between the command name and the ending MI file name to control things like output file name and sampling frequency. Most of these options do the same things as corresponding parameters in the MI's option block, but you can use them as convenient rendering switches. There's a couple of particularly useful options:
To display the output image as it's being rendered, use
ray -imgpipe 1 [MI file] | imf_disp -
To render the file on a network of machines, use
ray -hosts [host1] [host2] ... [MI file]
Another way to involve multiple hosts in the rendering is to create a text file called
.rayhosts which contains the names of the hosts, one per line, and place it in the current
directory or your home directory (constructed from the combination of