Multiline variables?

[Dan Kegel]

Hi all!
I innocently used this:

export PUB="$(base64 < ~/.ssh/id_rsa.pub)"
make

where Makefile is

all:
        echo "${PUB}"

and it worked fine on Mac, despite PUB being a multiline string.

On Ubuntu (even with the same version of gnu make),
it breaks terribly, complaining about a missing quote
on the end of the first line of the string.  Evidently this is not portable.

Clearly, I should use tr -d to remove newlines from the output of base64.

But in a better world, multiline strings would work in this situation.

I couldn't tell why they worked on the mac.  Any guesses?
- Dan