cabal-install follows the UNIX philosophy of do one thing and do it well: it builds your project and downloads your dependencies. However, cabal-install does not download ghc if one is needed (it can demand that a specific version of ghc is available). Unfortunately, many operating systems do not offer a way to install multiple versions of ghc.

ghcup makes it easy to install specific versions of ghc on GNU/Linux, and can also bootstrap a fresh Haskell developer environment from scratch.

Inspired by rustup, pyenv and jenv.

OS X users may prefer futurice and Ubuntu users may prefer hvr's ppa.

Table of Contents

• Installation
• Usage
• How
• Contributing
• Known problems

Installation

Just place the ghcup shell script into your PATH anywhere.

E.g.:

mkdir -p ~/.local/bin
curl https://raw.githubusercontent.com/haskell/ghcup/master/ghcup > ~/.local/bin/ghcup
chmod +x ~/.local/bin/ghcup

Then adjust your PATH in ~/.bashrc (or similar, depending on your shell) like so, for example:

export PATH="$HOME/.cabal/bin:$HOME/.ghcup/bin:$HOME/.local/bin:$PATH"

Usage

See ghcup --help.

How

Installs a specified GHC version into ~/.ghcup/ghc/<ver>, and places ghc-<ver> symlinks in ~/.ghcup/bin/.

Optionally, an unversioned ghc link can point to a default version of your choice.

This uses precompiled GHC binaries that have been compiled on fedora/debian by upstream GHC.

Alternatively, you can also tell it to compile from source (note that this might fail due to missing requirements).

In addition this script can also install cabal-install.

Contributing

• PR or email
• this script is POSIX shell
• use shellcheck and checkbashisms.pl from debian devscripts
• whitespaces, no tabs

Known problems

Limited distributions supported

Currently only GNU/Linux distributions compatible with the upstream GHC binaries are supported.

Precompiled binaries

Since this uses precompiled binaries you may run into problems with ncurses and missing libtinfo, in case your distribution doesn't use the legacy way of building ncurses and has no compatibility symlinks in place.

Ask your distributor on how to solve this or try to compile from source via ghcup compile <version>.

Unreliable download location

There is no single reliable URL where to download future GHC binary releases from, since the tarball names contain the distro name and version they were built on. As such, we cannot foresee what will be the next tarball name.

In such a case, consider to update this script via ghcup self-update.

Compilation

Although this script can compile GHC for you, it's just a very thin wrapper around the build system. It makes no effort in trying to figure out whether you have the correct toolchain and the correct dependencies. Refer to the official docs on how to prepare your environment for building GHC.