How can I change the version of npm using nvm?

EDIT: several years since this question was first answered, as noted in a newer answer, there is now a command for this:

nvm now has a command to update npm. It's nvm install-latest-npm or nvm install --latest-npm.

nvm install-latest-npm: Attempt to upgrade to the latest working npm on the current node version

nvm install --latest-npm: After installing, attempt to upgrade to the latest working npm on the given node version

Below are previous revisions of the correct answer to this question.

Over three years after this question was first asked, it seems like the answer is much simpler now. Just update the version that nvm installed, which lives in ~/.nvm/versions/node/[your-version]/lib/node_modules/npm.

I just installed node 4.2.2, which comes with npm 2.14.7, but I want to use npm 3. So I did:

cd ~/.nvm/versions/node/v4.2.2/lib
npm install npm

Easy!

And yes, this should work for any module, not just npm, that you want to be "global" for a specific version of node.

EDIT 1: In the newest version, npm -g is smart and installs modules into the path above instead of the system global path.

Thanks @philraj for pointing this out in a comment.

npm install [email protected] -g
npm install [email protected] -g

nvm doesn't handle npm.

So if you want to install node 0.4.x (which many packages still depend on) and use NPM, you can still use npm 1.0.x.

Install node 0.6.x (which comes with npm 1.1.x) and install nvm with npm:

npm install nvm
. ~/nvm/nvm.sh

Install node 0.4.x with nvm:

nvm install v0.4.12
nvm use v0.4.12

Install npm using install.sh (note the -L param to follow any redirects):

curl -L https://npmjs.org/install.sh | sh

This will detect node 0.4.12 and install npm 1.0.106 in your ~/nvm/v0.4.12/lib/node_modules folder and create symlink for nvm

~/nvm/v0.4.12/bin/npm -> ../lib/node_modules/npm/bin/npm-cli.js

If you try to run npm, it will still give an error but if you do nvm use v0.4.12 again, it should now work.

nvm now has a command to update npm. It's nvm install-latest-npm or npm install --latest-npm.

I'm on Windows and I couldn't get any of this stuff to work. I kept getting errors about files being in the way. This worked though:

cd %APPDATA%\nvm\v8.10.0           # or whatever version you're using
mv npm npm-old
mv npm.cmd npm-old.cmd
cd node_modules\
mv npm npm-old
cd npm-old\bin
node npm-cli.js i -g npm@latest

cd %APPDATA%\nvm\v8.10.0 # or whatever version you're using
rm npm-old
rm npm-old.cmd
cd node_modules\
rm -rf npm-old

And boom, I'm back in business.