OPAM is a package manager for OCaml. It builds and manages compiler versions and OCaml libraries for you easily.
The easiest way to install OPAM on your operating system is to use a package manager for your system. e.g apt-get, yum or homebrew.
Update homebrew formulae and install OPAM.
brew update brew install opam
add-apt-repository ppa:avsm/ppa apt-get update apt-get install ocaml opam
wget http://caml.inria.fr/pub/distrib/ocaml-4.03/ocaml-4.03.0.tar.gz tar xf ocaml-4.03.0.tar.gz cd ocaml-4.03.0 ./configure -prefix installation_path make world.opt make install
Once you have OPAM installed, run
opam init and follow the instructions.
Once done you should be able to run the OCaml interpreter from your shell.
$ ocaml OCaml version 4.03.0 #