Hi Perl Monks,

I have a question about flip flop operator ( /pattern/ .. /pattern/ ) and hope for your instructions/thoughts.

Suppose I have a text file like this :

start text

+ 123

+ 456

+ 789

some other text not starting with +

I would like to extract from "start text" to the one line before "some other text not starting with +". That is to say, in this example, to extract the first four lines.

I wrote a script like this - 

#!/usr/bin/perl
use strict; use warnings;

my $file = "file_name_to_the_txt";
open(my $fh,'<',$file) or die "Warnings: $!\n";
while (<$fh>) {
  print if (/^start/ .. /^\+/);
}
close ($fh);

[download]
===

but it only generates the first two lines. Is there a way to have a greedy flip flop operator? thanks in advance.

In reply to Greedy flip flop operator? by chengchl

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.