How to split a big tar files?

Easy 😉
split -b 100000000 thisfile.tar.gz thisfile.tar.gz

This will split your file into 100 MB parts with the thisfile name and suffix of gzaa, gzab, gzac, etc…

Then how to join them?

Easy too 😉
cat thisfile.tar.gz?? > thisfile.tar.gz

Until next time 🙂