gsplit

p:: CLI f:: Homebrew

brew install coreutils

gsplit -l 5000 -d --additional-suffix=.log $FileName file-

• -l 5000: split file into files of 5,000 lines each
• -d: numerical suffix. This will make the suffix go from 00 to 99 by default instead of aa to zz.
• --additional-suffix: lets you specify the suffix, here the extension $FileName: name of the file to be split.
• file: prefix to add to the resulting files.