$ sudo npm install postcss
$ sudo npm install -g postcss

If want to update the postcss package execute the command as below,

$ sudo npm update postcss

Update package globally,

$ npm install -g postcss

Git clone:

$ sudo  git clone https://github.com/rektide/postcss.git

$ sudo  npm install -g ./postcss

postcss@6.0.14 /usr/lib/node_modules/postcss

How to remove postcss package :

You can uninstall or remove this package from your node_modules run the command as below,

$ sudo npm uninstall postcss

Basic Information of postcss NPM Package: