You can install Node.js on your machine. It serves to run several applications that you can download at NPM , including the Gulp .
Gulp automates various operations for you. Coupled with gulp-sass , for example, you can compile your SASS files automatically each time you save them - plugin keeps observing the directory where they are and reacts to changes.
For LESS, you can use gulp-less . The principle is the same.
The instructions for using gulp and its plugins are on each page. There are only a few script lines for each of them.
Just a warning: Node.js is already addictive by itself, but its combination with NPM leads to a non-return path:)