Hi alwynpan,

The special variable $, controls what print outputs between its arguments. See also $" and $\.

local $" = "a";  # list separator
local $, = "c";  # output field separator
local $\ = "l";  # output record separator
my @x = ('F','O');
print @x, "@x", "x";  # prints "FcOcFaOcxl"
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So $" controls what is inserted between elements when the array @x is interpolated into a string. Normally, it'd turn out to be "F O", but since we've redefined $", we get "FaO".

Next, $, controls what gets output between the arguments of print. Since the argument list is "flattened" and the elements of the array @x each become an argument to the function, the above is as if we had written print "F", "O", "FaO", "x" (this is a little bit of a simplification but good enough in this example). So the value of $, is inserted in between every argument.

Lastly, $\ is simply what print outputs at the end of the argument list. It can be useful to set it to something like "\n", but note that this affects every print statement, which is why doing so is not always a good idea in larger programs. That's also why I've used local above, because that'll limit the effect of the assignment to the current dynamic scope only.

As you can see variable names can be special characters, but Perl already uses a lot of them for special meanings, so you shouldn't try and make your own! Just use the ones Perl provides, when you need to. See perlvar. Update: Also, shmem makes an excellent point!

By the way, the code you posted shows some fairly advanced techniques, I would not recommend it as something to study for your "first day"!

Hope this helps,
-- Hauke D