How to force vim to syntax-highlight a file as html?

:set syntax=html

You can also put this into your .vimrc:

au BufReadPost *.ezt set syntax=html

Take a look at this Vim wikia topic. Some useful tips:

• As other answers have mentioned, you can use the vim set command to set syntax. :set syntax=<type> where <type> is something like perl, html, php, etc.

• There is another mechanism that can be used to control syntax highlighting called filetype, or ft for short. Similar to syntax, you give it a type like this: :set filetype=html. Other filetypes are perl, php, etc.

• Sometimes vim "forgets" what syntax to use, especially if you're mixing things like php and html together. Use the keyboard shortcut Ctrl+L (<C-L>) to get vim to refresh the highlighting.

To make it automatic, add this line to your ~/.vimrc:

autocmd BufNewFile,BufRead *.ezt set filetype=html

If you want to just do it for the current file, then type:

:set filetype=html

You could also substitute syntax instead of filetype, but filetype affects more things than syntax (including syntax highlighting, indenting rules, and plugins), so generally you should use filetype unless you only want to affect syntax.