G'day jwkuo87,

Welcome to the monastery.

The following technique uses paragraph instead of slurp mode (see $/ in perlvar: Variables related to filehandles). This gets around matching Chapter 2 in the TOC.

I've also used the '..' range operator (which davido showed earlier).

Finally, we stop reading the input file as soon as Chapter 3 is found.

Here's the code. Note that, for testing purposes, I've added a second (dummy) paragraph to Chapter 2 and truncated the existing first paragraph. 

#!/usr/bin/env perl

use strict;
use warnings;

{
    local $/ = '';

    while (<DATA>) {
        next unless /^Chapter 2/ .. /^Chapter 3/;
        last if /^Chapter 3/;
        print;
    }
}

__DATA__
Table of Contents
Chapter 1. Introduction
Chapter 2. Main
Chapter 3. Conclusion

==============================

Chapter 1. Introduction
This is the introduction preceding Chapter 2.

Chapter 2. Main
This is the text contained in Chapter 2 and will ...

Assume more than one paragraph.

Chapter 3. Conclusion
This is the conclusion.

[download]

Output:

Chapter 2. Main
This is the text contained in Chapter 2 and will ...

Assume more than one paragraph.

[download]

-- Ken

In reply to Re: Extracting a chapter from text file by kcott
in thread Extracting a chapter from text file by jwkuo87

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.