The installation command for OPAM is:
wget https://raw.github.com/ocaml/opam/master/shell/opam_installer.sh -O - | sh -s /usr/local/bin
On macOS you can get opam through Homebrew with brew install opam. Consult https://opam.ocaml.org/doc/Install.html for other ways to install OPAM.
After installing OPAM, you need to initialize its state with:
opam init eval `opam config env` opam update
Once you have OPAM ready, install Coq 8.6.1 by:
opam install coq.8.6.1
We recommend you install Haskell using Stack. The generic command to install Stack is:
curl -sSL https://get.haskellstack.org/ | sh
On macOS, we recommend you use Homebrew to install Stack with brew install haskell-stack, though you can use the curl command above.
More installation instructions: https://docs.haskellstack.org/en/stable/install_and_upgrade/
Questions or comments regarding 6.826? Contact us on Piazza or send e-mail to the 6.826 staff at firstname.lastname@example.org.