Eu estava usando o ubuntu16.04 atualizado para o ubuntu18.04. segui algum tutorial para remover npm, mas agora preso. Eu tenho:
~$ npm list -g
bash: /usr/bin/npm: No such file or directory
e:
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.
Eu estava tendo o mesmo problema. Depois de muita pesquisa on-line, consegui encontrar uma solução.
O que se segue é o que resolveu para mim:
sudo apt-get remove nodejs npm
sudo apt-get update
sudo apt-get upgrade
curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
sudo apt-get install -y nodejs
Teste a instalação:
~$ nodejs -v
v8.11.3
~$ npm -v
5.6.0