% apt-file search zsh. | egrep --color=always 'zsh\.'

... if using egrep, the above makes sure that the dot is taken 
literally.  I have a function that ends up trying to create the above:

     % func 'zsh\.'

... which will attempt:

     apt-file search "$1" | egrep --color=always $1

... and it works fine unless I want to force a literal char, as above.  
zsh is removing the quotes as she properly does, but in this case I need 
to preserve them since egrep needs them.  I know I've done this before.  
Something in the (Q) continuum?  It has to be egrep since I normally 
want the regex interpretation, it's just this odd case where I need a 
regex char forced literal.   I know it's doable.