NPM is incorrect version on latest Ubuntu (18.04) installation

Normal installation would be sudo apt install nodejs to install Node.js and then sudo apt install npm to install Node Package Manager. However, upon doing so, npm -v says 3.5.2. To upgrade normally, I would do sudo npm install -g npm, which updates to the latest version (which, at the time of writing this article, is 6.0.1).

When I do a which npm, I get /usr/local/bin/npm, however apt installs a symlink at /usr/bin/npm. If I sudo apt purge npm to remove npm, it still leaves the npm version of npm at /usr/local/bin/npm, however npm -v says -bash: /usr/bin/npm: No such file or directory.

Many articles say to use a PPA to install nodejs, but I think there should be a native way to do this through apt.

DigitalOcean instructions on installation normally and through PPA: https://www.digitalocean.com/community/tutorials/how-to-install-node-js-on-ubuntu-18-04

TecAdmin instructions on installation through PPA: https://tecadmin.net/install-latest-nodejs-npm-on-ubuntu/

Solution 1:

TLDR: This problem is caused by Bash caching the path of the npm command, and can be solved by hash -d npm. You don't even need to deal with apt purge unless you want to.

Explanation

Here were my steps for getting a new npm version on Ubuntu. First, do the installation as OP describes:

$ sudo apt-get install npm
(...apt installation of npm was successful...)
$ npm -v
3.5.2
$ command -v npm
/usr/bin/npm
$ sudo npm install -g npm
(...npm installation of npm was successful...so far, so good)

You can see that the new version is already working fine in /usr/local/bin/npm, but unfortunately the Bash cache still has /usr/bin/npm:

$ /usr/local/bin/npm -v
6.4.1
$ npm -v
3.5.2
$ command -v npm
/usr/bin/npm
$ type npm
npm is hashed (/usr/bin/npm)

To fix the problem, clear it from the Bash cache (do this in all open shells):

$ hash -d npm

Now the new version works as desired:

$ npm -v
6.4.1
$ command -v npm
/usr/local/bin/npm

Solution 2:

The way I found is to purge npm through sudo apt purge npm, then simply recreate a symlink to the global installation via ln -s /usr/local/bin/npm /usr/bin/npm. After that fix, npm -v returns 6.0.1 as expected.