You can compress the required file to a zip (or rar) file, setting a maximum file size so that it gets split. This means that you will always have the program to get the initial file back available.
Some options are:
- HJSplit is a freeware and portable (size == 300 KB), and doesn’t have to be installed.
- There is an older, free command-line version of Goetz’s File Splitter, it is best if you plan on running batch scripts to split many files.
- 7-Zip is another free open source program that allows you to split (with or without compression) and combine files, either via GUI (right click on the file > Split File… > choose size) or command line.
- Total Commander does that as well (Files > Split File…).