How to create a new vim filetype?

Question

I have html settings set up in my ~/.vim/ftplugin/html.vim file. I would like these settings to apply to Rhtml files as well. I made a symbolic link with

ln -s ~/.vim/ftplugin/html.vim ~/.vim/ftplugin/Rhtml.vim

Why doesn't this load my html settings when I open a .Rhtml file?

Answer 1

The symlink you've created at ~/.vim/ftplugin/Rhtml.vim tells Vim how to handle files with the RHTML filetype, but you haven't told Vim how to recognise which files should have this filetype.

Instructions for how to do so can be found in the documentation by running the command :help new-filetype.

You can use either the technique described in section A or the one from section C for your purposes. (The former is arguably simpler, but has a couple of disadvantages compared to the latter, which are described in the docs.)

Answer 2

Create ~/.vim/ftdetect/SOME_EXTENSION.vim and add this line to it:

autocmd BufNewFile,BufRead *.SOME_EXTENSION set filetype=SOME_FILETYPE

So if you wanted vim to use the filetype html for all files with an .Rhtml extension you would add this to ~/.vim/ftdetect/rhtml.vim:

autocmd BufNewFile,BufRead *.Rhtml set filetype=html