npm install -g fails with 'npm ERR! code EACCES ... permission denied, mkdir /usr/local/lib/node_modules' (or access '/usr/lib/node_modules'). How do I fix it without sudo?

Cause: global installs (npm install -g) write into npm's global prefix. When Node was installed from the official installer or a system package, that prefix is a system directory such as /usr/local or /usr owned by root, so a normal user gets EACCES. Running with sudo 'works' but runs package install scripts as root and leaves root-owned files in your home directory (~/.npm), which then cause more EACCES errors later. Fix (npm's recommended options, best first): 1. Use a Node version manager (nvm, fnm, Volta, or the Node.js installer page's recommended manager). It installs Node under your home directory, so global installs need no sudo. Example with nvm: install nvm, then nvm install --lts and nvm use --lts, and reinstall your global tools. 2. Or change npm's global prefix to a directory you own: mkdir -p ~/.npm-global npm config set prefix ~/.npm-global add export PATH=~/.npm-global/bin:$PATH to your shell profile, then reload it. 3. Avoid global installs where you can: run tools with npx <tool>, or add them as devDependencies and run them through npm scripts. 4. If earlier sudo runs left root-owned files, fix ownership of your cache: sudo chown -R $(id -u):$(id -g) ~/.npm. 5. Don't chmod -R 777 or chown system directories like /usr/lib; it weakens the whole system. 6. In Docker images, either install globals as root during the build on purpose, or set the prefix as above for a non-root user. Verify: npm config get prefix points to a directory you own, npm install -g <tool> works without sudo, and the tool is on PATH (which <tool>). Sources: https://docs.npmjs.com/resolving-eacces-permissions-errors-when-installing-packages-globally https://github.com/nvm-sh/nvm