Mac OS X Disk Utility commands
For my fist post I thought I would keep it simple. The following are two commands related to disk images in OS X. The first one will take Old.dmg from you home folder and split it up into multiple files each with a max size of 50MB. The nice thing is that you do not have to reassemble them to open the dmg. You just double click the main file and it will grab all the data from the separate files and mount it as normal.
hdiutil segment -o ~/New.dmg -segmentSize 50m ~/Old.dmg
The next command is even more simple. It just converts discimage.dmg to an ISO.
hdiutil convert discimage.dmg -format UDTO -o discimage.iso