To install Haskell, if you are running Linux, macOS, FreeBSD or Windows Subsystem for Linux, run the following
in your terminal (as a user other than root), then follow the onscreen instructions.
curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
If you don't like curl | sh, see other installation methods.