Error while installing node.js, npm and serverless - node.js

Question

I am trying to install node.js and npm in my laptop using the following commands found here:
# Using Ubuntu
curl -sL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt-get install -y nodejs
These install Node.js LTS (v12.x).
After this, I am trying to install serverless as shown here.
I do:
npm install -g serverless
and it throws the following error
cortex#cortex-Lenovo-ideapad-720S-15IKB:~$ npm install -g serverless
npm WARN deprecated #types/chalk#2.2.0: This is a stub types definition for chalk (https://github.com/chalk/chalk). chalk provides its own type definitions, so you don't need #types/chalk installed!
npm WARN deprecated request#2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated request-promise-native#1.0.9: request-promise-native has been deprecated because it extends the now deprecated request package, see https://github.com/request/request/issues/3142
npm WARN deprecated har-validator#5.1.5: this library is no longer supported
npm WARN deprecated urix#0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated resolve-url#0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN checkPermissions Missing write access to /usr/lib/node_modules
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents#~2.1.2 (node_modules/serverless/node_modules/chokidar/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents#2.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm ERR! code EACCES
npm ERR! syscall access
npm ERR! path /usr/lib/node_modules
npm ERR! errno -13
npm ERR! Error: EACCES: permission denied, access '/usr/lib/node_modules'
npm ERR! [Error: EACCES: permission denied, access '/usr/lib/node_modules'] {
npm ERR! errno: -13,
npm ERR! code: 'EACCES',
npm ERR! syscall: 'access',
npm ERR! path: '/usr/lib/node_modules'
npm ERR! }
npm ERR!
npm ERR! The operation was rejected by your operating system.
npm ERR! It is likely you do not have the permissions to access this file as the current user
npm ERR!
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.
npm ERR! A complete log of this run can be found in:
npm ERR! /home/cortex/.npm/_logs/2020-08-19T14_04_41_850Z-debug.log
I am completely new to node.js, so can anyone please help me out with this?
P.S.:
output of node -v is v12.18.3
output of npm -v is 6.14.6

Answer 1

Use sudo when installing a global package.
sudo npm install -g serverless