If you use Vim’s syntax highligting you may notice that not all files get correct highlighting, when opened in Vim. To quickly add a file extension to Vim, you can add the extension to your ~/.vimrc file.

syntax on
filetype on
autocmd BufNewFile,BufRead *.pp set filetype=ruby

In the example above, files with a ‘.pp’ extension get ruby syntax highlighting. See ‘:help autocmd’ in Vim for details on autocmd.