autocmd check filename in vim?

Question

I want to write some autocmd's that check if the filename is this or that..

I've been trying:

autocmd VimEnter * if % is "preamble" | Explore | endif
autocmd VimEnter * if %=="preamble" | Explore | endif
autocmd VimEnter * if &filename == "preamble" | Explore | endif

but none of this works?

WHat should I do?

(this example is over-simplified, note that I'd also like to have an else statement).

Whip

I doubt whether VimEnter is the best event to trigger this autocmd. VimEnter happens once when you start a Vim instance and not after that. BufRead happens each time a buffer is opened, regardless of whether Vim was open already or not (and likewise with BufNewFile). – Manysided

Yeah I'm actually using BufNew to make it work – Whip

Thank you all for your swift responses! – Whip

This is what I'm using to change the color scheme except if the current buffer is a MiniBufExpl bufer and it seems to be working: autocmd BufEnter * if bufname("%") !=? '-MiniBufExplorer-' | colorscheme default | endif – Prairie

Answer 1

You should get the current file name as @%. For e.g., echo @% will give you the filename, whereas echo % will not. However, for actions on the file, use %, e.g. source %.

This should probably work for what you want to do:

autocmd VimEnter * if @% == 'preamble' | echo 'hello' | else | echo 'world' | endif

Stammel

Is it possible to do more than one thing in 'if' part or 'else' part? e.g. autocmd VimEnter * if @% == 'preamble' | echo 'hello1'; echo 'hello2' | else | echo 'world1'; echo 'world2' | endif – Standpipe

Answer 2

autocmd BufRead,BufNewFile preamble Explore

Mitch

Ok this works.. I would also like to have an else statement. Is this possible? – Whip

@romeoevs: For effect of an else one way is to just create another autocmd that matches everything except 'preamble'. I think this would do it: autocmd BufRead, BufNewFile [^\(preamble\)] function_here (See my separate Answer for info on what you were doing wrong and how the file-slot in autocmd works.) – Manysided

Answer 3

There are two problems with the examples in the original post:

1. Neither the % nor &filename will return the filename as you've used them.
   Look at the help for the expand() function to see how to get the filename: :h expand()

2. You're ignoring the slot in autocmd where a file-matching-pattern would ordinarily be specified. The third slot in the autocmd (* in your versions) is actually a pattern to match filenames. See :h autocmd-patterns. It should work okay if you want to ignore the pattern slot, but if so, you've got to fix the problem in paragraph 1 above. E.g.,

   autocmd BufRead,BufNewFile * if expand('%') =~ "preamble" | Explore | endif

Manysided

Answer 4

Additional Info Using '@%' with autocmd

Some autocmd events do not support the @% named register to read the current file name. In these cases it is better to use <afile>:

expand('<afile>')

Skyrocket