Wie entferne ich npm und installiere npm in 18.04 komplett neu?

Ich habe ubuntu16.04 verwendet und auf ubuntu18.04 aktualisiert. folgte ein Tutorial, um npm zu entfernen, aber jetzt stecken. Ich habe:

~$ npm list -g 
bash: /usr/bin/npm: No such file or directory

und:

     sudo apt-get install npm
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 npm : Depends: nodejs but it is not going to be installed
       Depends: node-abbrev (>= 1.0.4) but it is not going to be installed
       Depends: node-ansi (>= 0.3.0-2) but it is not going to be installed
       Depends: node-ansi-color-table but it is not going to be installed
       Depends: node-archy but it is not going to be installed
       Depends: node-block-stream but it is not going to be installed
       Depends: node-fstream (>= 0.1.22) but it is not going to be installed
       Depends: node-fstream-ignore but it is not going to be installed
       Depends: node-github-url-from-git but it is not going to be installed
       Depends: node-glob (>= 3.1.21) but it is not going to be installed
       Depends: node-graceful-fs (>= 2.0.0) but it is not going to be installed
       Depends: node-inherits but it is not going to be installed
       Depends: node-ini (>= 1.1.0) but it is not going to be installed
       Depends: node-lockfile but it is not going to be installed
       Depends: node-lru-cache (>= 2.3.0) but it is not going to be installed
       Depends: node-minimatch (>= 0.2.11) but it is not going to be installed
       Depends: node-mkdirp (>= 0.3.3) but it is not going to be installed
       Depends: node-gyp (>= 0.10.9) but it is not going to be installed
       Depends: node-nopt (>= 3.0.1) but it is not going to be installed
       Depends: node-npmlog but it is not going to be installed
       Depends: node-once but it is not going to be installed
       Depends: node-osenv but it is not going to be installed
       Depends: node-read but it is not going to be installed
       Depends: node-read-package-json (>= 1.1.0) but it is not going to be installed
       Depends: node-request (>= 2.25.0) but it is not going to be installed
       Depends: node-retry but it is not going to be installed
       Depends: node-rimraf (>= 2.2.2) but it is not going to be installed
       Depends: node-semver (>= 2.1.0) but it is not going to be installed
       Depends: node-sha but it is not going to be installed
       Depends: node-slide but it is not going to be installed
       Depends: node-tar (>= 0.1.18) but it is not going to be installed
       Depends: node-underscore but it is not going to be installed
       Depends: node-which but it is not going to be installed
      E: Unable to correct problems, you have held broken packages.

Ich hatte das gleiche Problem. Nach langem Suchen im Internet konnte ich eine Lösung finden.

Folgendes hat es für mich gelöst:

Entfernen Sie alte NodeJS-Installations- und Update-Pakete.

sudo apt-get remove nodejs npm
sudo apt-get update
sudo apt-get upgrade

Für 8.x-Knoteninstallationen:

curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -

Für 12.x-Knoteninstallationen:

curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -

Installieren:

sudo apt-get install -y nodejs

Testen Sie die Installation:

~$ nodejs -v
v8.11.3 // <- node 8.x
v12.13.1  // <- node 12.x

~$ npm -v
5.6.0 // <- node 8.x 
6.12.1 // <- node 12.x