nvm-sh/nvm

nvm, short for Node Version Manager, is a command-line tool that lets a developer install many different versions of Node.js on the same computer and switch between them with one command. Node.js is a runtime that lets JavaScript code run outside a web browser, used to build servers, command-line tools, and other JavaScript-based software. Different projects often expect different Node versions, and nvm makes it possible to keep all of them ready and pick the right one for whichever project is currently open. The README describes nvm as a POSIX-compliant shell script, meaning a small program written in shell language that works under sh, dash, ksh, zsh, and bash on Unix, macOS, and Windows Subsystem for Linux. It is installed once per user and activated per shell session. Typical usage shown in the README is short: nvm install 24 downloads and switches to Node 24, nvm use 22 switches to a previously installed version, and node -v confirms which is active. There is also a long-term-support helper, an offline-install option, a way to migrate global packages between versions while installing, and an .nvmrc file that lets a project record the version it expects so nvm picks it up automatically. People typically reach for nvm when one project needs an older Node and another needs the latest, when reproducing a bug that only appears on a specific version, or when configuring CI/CD images. The README walks through install scripts using curl or wget, manual and Docker-based installs, troubleshooting on Linux and macOS, shell-completion setup, and steps for uninstalling.