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POClarification on chomp
 

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    <p>I'm on break from classes right now and decided to spend my time learning Perl. I'm working with Beginning Perl (<a href="http://www.perl.org/books/beginning-perl/" rel="nofollow">http://www.perl.org/books/beginning-perl/</a>) and I'm finishing up the exercises at the end of chapter three.</p> <p>One of the exercises asked that I "Store your important phone numbers in a hash. Write a program to look up numbers by the person's name."</p> <p>Anyway, I had come up with this: </p> <pre><code>#!/usr/bin/perl use warnings; use strict; my %name_number= ( Me =&gt; "XXX XXX XXXX", Home =&gt; "YYY YYY YYYY", Emergency =&gt; "ZZZ ZZZ ZZZZ", Lookup =&gt; "411" ); print "Enter the name of who you want to call (Me, Home, Emergency, Lookup)", "\n"; my $input = &lt;STDIN&gt;; print "$input can be reached at $name_number{$input}\n"; </code></pre> <p>And it just wouldn't work. I kept getting this error message:</p> <blockquote> <p>Use of uninitialized value in concatenation (.) or string at hello.plx line 17, line 1</p> </blockquote> <p>I tried playing around with the code some more but each "solution" looked more complex than the "solution" that came before it. Finally, I decided to check the answers.</p> <p>The only difference between my code and the answer was the presence of <code>chomp ($input);</code> after <code>&lt;STDIN&gt;;</code>.</p> <p>Now, the author has used <code>chomp</code> in previous example but he didn't really cover what <code>chomp</code> was doing. So, I found this answer on www.perlmeme.org:</p> <blockquote> <p>The <code>chomp()</code> function will remove (usually) any newline character from the end of a string. The reason we say usually is that it actually removes any character that matches the current value of <code>$/</code> (the input record separator), and <code>$/</code> defaults to a newline..</p> </blockquote> <hr> <p>Anyway, my questions are:</p> <ol> <li><p>What newlines are getting removed? Does Perl automatically append a <code>"\n"</code> to the input from <code>&lt;STDIN&gt;</code>? I'm just a little unclear because when I read "it actually removes any character that matches the current value of <code>$/</code>", I can't help but think "I don't remember putting a <code>$/</code> anywhere in my code."</p></li> <li><p>I'd like to develop best practices as soon as possible - is it best to always include <code>chomp</code> after <code>&lt;STDIN&gt;</code> or are there scenarios where it's unnecessary?</p></li> </ol>
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    1. CO`perldoc -f chomp` or [perlfunc](http://perldoc.perl.org/perlfunc.html)
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    2. COOkay, so the chomp entry in Perlmeme's FAQ (http://www.perlmeme.org/faqs/manipulating_text/chomp.html) answers most of my first question. That is, the FAQ leads me to believe that Perl does automatically a newline (not necessarily at "\n" but a newline just the same). But am I understanding that correctly?
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    3. COContinuing with the link from perlfunc: [chomp](http://perldoc.perl.org/functions/chomp.html) which covers the use of the separator.
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