Controlled installation of Lean 4 on Debian/Ubuntu #

Note that these are legacy instructions provided by the community. The recommended way to install Lean and to create a project is to follow the instructions in the official Lean documentation.

Legacy instructions #

This document explains a more controlled installation procedure for Lean 4 and mathlib on Linux distributions derived from Debian (Debian itself, Ubuntu, LMDE,...). There is a quicker way described in the main install page but it requires more trust. Of course you can get even more details about what is going on by reading the bash script that will be downloaded below: elan_init.

• Lean itself doesn't depend on much infrastructure, but supporting tools needed by most users require git and curl. So the first step is:

  sudo apt install git curl
  

• The next step installs a small tool called elan which will handle updating Lean according to the needs of your current project (hit Enter when a question is asked). It will live in $HOME/.elan and adds a line to $HOME/.profile.

  curl https://elan.lean-lang.org/elan-init.sh -sSf | sh
  

• There are three editors you can use with Lean, VS Code, emacs and neovim. The recommended choice is Visual Studio Code which has the most complete and well-tested support for Lean.

  wget -O code.deb https://go.microsoft.com/fwlink/?LinkID=760868
  sudo apt install ./code.deb
  rm code.deb
  code --install-extension leanprover.lean4
  

  Now open VS Code, and verify Lean is working, for example by saving a file test.lean and entering #eval 1+1. A green line should appear underneath #eval 1+1, and hovering the mouse over it you should see 2 displayed.

  Alternatively, you can use Emacs and its lean4-mode or neovim and its lean.nvim extension.

Lean Projects #

You can now read instructions about creating and working on Lean projects