How can I split a 60 GB file into 5 GB pieces on a Mac?
OS X includes a command line tool called split. See man split for all the details.

You can call split using the Terminal.app and the command:

split -b 5000m MYBIGFILE




To combine it again, have the receiver store all parts in a dedicated folder, open Terminal there and run

cat x?? &gt; MYBIGFILE


(This assumes that you used the default output names when running split.)