I am on Ubuntu 20 and Ocaml already correctly worked on my OS.
Even after
sudo apt remove ocaml
sudo apt autoremove ocaml
sudo apt purge ocaml
sudo apt autoremove --purge ocaml
installing Ocaml with sudo apt install ocaml (after update and upgrade) and typing eg ocaml --help result in:
bash: /usr/bin/ocaml: /usr/bin/ocamlrun: bad interpreter: No such file or directory
And it is true that /usr/bin/ contains no ocamlrun file or folder.
KR Zlotz