Say you have a big file and you want to zip it up into a few smaller files, (coz email attachment has size limit), here is how you do it.
zip -s 5m file.zip myBigFile.mov
That cmd will create these files with file size capped at 5mb
To get your original file back, install 7zip.
brew install p7zip
Then run the following to extract your original file(s) back
7za x file.zip
There are other ways but I found the above the easiest.