Differentiate common linux binaries from Bash

[lhoursquentin]

There should be at least an introduction saying that the presented binaries (grep, find, mkdir ...) aren't part of bash and can be used by any other shell or programming language and are just part of unix commonly used binaries. Just let them know this isn't Bash specific.

Bash builtins should at the contrary be highlighted (export, cd ...) to be differentiated from the binaries.

[Idnan]

Hi, thank you for reporting. I will fix it. In the meantime PR are welcome :)