[Techtalk] Learning Perl!!!!

[Katie Bechtold]

On Wed, Sep 11, 2002 at 04:10:17PM -0700, kansas_kennedy at phreaker.net wrote:
> 2) What is the big fuss about 'foobar'? what is it exactly in Linux? Does 
> it have any significance (like /dev/null)? I seen it being also used in 
> Learning Perl book.

>From The Jargon File
(http://www.tuxedo.org/jargon/html/entry/foobar.html) :

foobar
Another widely used metasyntactic variable; see foo for etymology.

metasyntactic variable
A name used in examples and understood to stand for whatever thing
is under discussion, or any random member of a class of things under
discussion.  The word foo is the canonical example.

> 3) And I am having some trouble with the problem in section 2.2.1.1 in Page 
> 23 of Picking up Perl pdf. I don't understand why they are using " ' ' 
> "  and then " "" " sort of alternatively. So far I learned that single 
> quotes are used when we don't want to interpret anything and keep it as it 
> is and double-quotes are used for interpolation. 

Here's the example:

#!/usr/bin/perl

use strict;
use warnings;

print 2E-2, ' ', 9.77E-5, " ", 100.00, " ", 100_181_973, ' ',
9.87E9, " ", 86.7E14, "\n";

Now, you're correct that double quotation marks do variable
interpolation and backslash interpolation while single quotes
suppress interpolation.  But I don't get the same results if I use
either one.  When I run the example as is, I get:

[katie at blue katie]$ test.pl
0.02 9.77e-05 100 100181973 9870000000 8.67e+15
[katie at blue katie]$ 

But if I replace the double quotes around \n with single quotes, I
get this:

[katie at blue katie]$ test.pl
0.02 9.77e-05 100 100181973 9870000000 8.67e+15\n[katie at blue katie]$ 

In this case, the newline \n was not interpolated but interpreted
literally.  Am I to understand you don't get the same results I do?

-- 
Katie Bechtold
http://katie-and-rob.org/