It's about writing modules/extensions for an existing system. Traditional Unix programs make your shell environment work better. Adblock Plus, Perspectives, T

It's about writing modules/extensions for an existing system. Traditional Unix programs make your shell environment work better. Adblock Plus, Perspectives, Tree Style Tab, etc, make my Iceweasel work better. mod_rewrite, mod_php, etc, make Apache work better. The "text streams" part is specific to Unix, because files and pipes are the defining feature of that environment. The other parts are probably universal across any extensible system.