What it is
nvm is a per-user shell script that downloads, installs, and switches between multiple Node.js releases from the command line. It works in POSIX shells such as bash, zsh, dash, and ksh on Linux, macOS, and Windows WSL, and can pick a version automatically from a project's .nvmrc file. JavaScript developers use it to test code against different Node releases, keep LTS and current versions side by side, and migrate global npm packages between installs.