Andreas Schwab wrote:

> Jim Meyering <jim@meye...> writes:
>
>> Andreas Schwab wrote:
>>> Jim Meyering <jim@meye...> writes:
>>>
>>>> (note that below there's the added advantage of not having to
>>>> double-quote to include $nl and hence not having to double-backslash)
>>>
>>> You can have that with the variable as well.
>>
>> You're right.  We could write it like this:
>>
>>     printf '\na\nb'|tac -rs '.\|'$nl
>
> No, you need the quotes around $nl.

You need the double quotes around $nl with bash,
but not with zsh:

    zsh$ nl='
    quote> '
    zsh$ printf %s $nl

    zsh$