What are the alternatives to vi's command :hi Comment in Emacs?

[heartless]

Hello,
I'm looking for an alternative of vi's command: :hi Comment... in Emacs,
anyone knows?

p.s Is there a method to turn off background complitely in Emacs?

Thanks,

 

[J77]

What does the vi command do?

 

[heartless]

oh, sorry for not mentioning. It highlights all the comments in a text.

 

[J77]

In emacs you generally have .el (elisp) files which, as one option - stuff will appear as buttons at the top of your window, allow you to highlight...

eg. If you have the matlab.el file, you can highlight all the MATLAB commands...

Also lots of these will be built in (with the emacs compilation), eg. global highlighting for c++ (.cc) files and .tex files + executables .sh

Plain text though, I'm not sure...

Assuming it's .txt, hit the Options button at the top of the window and switch on the global highlighting - though I can't think what it would highlight in a standard txt file?