See: https://fortran-lang.discourse.group/t/intel-releases-oneapi-toolkit-free-fortran-2018/471/43
If you just install the package intel-oneapi-compiler-fortran, it takes less than 2 GB on your hard drive.
And it’s important to know that when a new version is available, it does not replace the previous one, but is added to. I therefore remove the previous one with Synaptic to limit the space occupied on disk.
For setvars.sh see also: https://fortran-lang.discourse.group/t/intel-releases-oneapi-toolkit-free-fortran-2018/471/74