> >>> I want to know whether there are some similar regexp
> >>> patterns in Emacs as the ones used by grep, say, $'\014'
> >>> or $'\f'.
> >>
> >> (re-search-forward "\C-l")
> >
> > Yes, or (re-search-forward "[\f]")
> >      or (re-search-forward "[\014]")
> 
> What about
> 
>   (re-search-forward (kbd "C-l"))

Sure.  Which is the same as (re-search-forward "\f").