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.