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

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

$ sudo npm update postcss-cssnext

Update package globally,

$ npm install -g postcss-cssnext

Git clone:

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

$ sudo  npm install -g ./postcss-cssnext

postcss-cssnext@3.0.2 /usr/lib/node_modules/postcss-cssnext

How to remove postcss-cssnext package :

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

$ sudo npm uninstall postcss-cssnext

Basic Information of postcss-cssnext NPM Package: