elan vs eselect-python

elan manages installations of the Lean theorem prover on Linux, macOS and Windows. Its `lean` and `lake` binaries use a project’s `lean-toolchain` file to select the specified Lean version and download it when needed. The separate `elan` command provides manual control to install, select, run or uninstall Lean versions. The project supports version pinning, lockfiles, automatic switching, shell integration and CI/CD use. Installation options include shell instructions for Linux and macOS, a PowerShell method for Windows, and release downloads for supported platforms. The README recommends the Nixpkgs version on NixOS because toolchains downloaded by elan require patching there. Lake needs git to download dependencies. The project describes itself as a fork of rustup adapted for Lean infrastructure. elan is free at free, and the repository lists Apache-2.0 and MIT licenses. The releases page identifies v4.2.4 as the latest release.

eselect-python has no write-up on Specifiction yet; its figures are above.