elan vs fnm

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.

fnm is a free Node.js version manager built in Rust for developers working from a command line or shell. It runs on macOS, Windows, and Linux, and is distributed as a single file through installation scripts, package managers, Cargo, or release binaries. It reads `.node-version` and `.nvmrc` files, so projects can specify a Node.js version. Shell setup can also enable automatic version switching when changing directories. The project provides setup instructions for Bash, Zsh, Fish, PowerShell, Windows Command Prompt, and Cmder. Its binary includes completions for Bash, Zsh, Fish, and PowerShell. On macOS and Linux, the installation script requires `curl` and `unzip`. The repository identifies the license as GPL-3.0 and invites pull requests, with issues available for project interaction. No paid plans are listed. The project page reports no published security advisories, while also noting that it has not set up a SECURITY.md file.