When Creating a new Angular 5 project:
node version: 8.9.2
npm version: 5.5.1
My Command is
npm install -g @angular/cli
If npm cache clean --force doesn't resolve the issue, try deleting the ~/.npm directory (*nix/macOS). This is the directory where node stores its cache, locks, logs, global packages (unless you're using nvm), and modules installed via npx.
First, backup your current ~./npm directory:
mv ~/.npm ~/.npm-backup
Now try running your npm command again. This will create a new ~/.npm directory. If the issue is resolved, you can safely remove you backup. Before doing so, you may want to review the global packages installed in your ~/.npm-backup directory so you can reinstall them using npm i -g [package].
rm -rf ~/.npm-backup
If the issue is not resolved, you can restore your backup:
rm -rf ~/.npm
mv ~/.npm-backup ~/.npm
Careful with those rm commands, folks!