in reply to Matching range of text with another string in between

Welcome to the Monastery, periodicalcoder!

If the last line of each entry will always be CAS*, you can split up the file into chunks by setting the record separator ($/) to that, then configure your regex to match across newlines (/m) and to match newlines (/s). The zero-width lookahead (?:...) ensures that '00003' comes after "LX*" and before the record separator ("CAS*").

use warnings;
use strict;

open my $fh, '<', 'file.txt' or die $!;

{
    local $/ = 'CAS*';
    while (<$fh>){
        print $_ if /LX\*.*(?=00003$)/ms;
    }
}

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Re^2: Matching range of text with another string in between
by GrandFather (Saint) on Apr 22, 2016 at 03:30 UTC

    The /m isn't required. /m enables the multi-line mode which allows ^ and $ to match embedded newline characters.

    Update: Argh! I missed seeing the $ in stevieb's reply. I apologise to periodicalcoder for causing confusion and to stevieb for being silly!

    Premature optimization is the root of all job security
[reply]

      Stevieb and GrandFather, thank you for your replies. I feel that we are heading in the right direction, but I have a few questions.

      First, I should have been more thorough in my question. What you gave me does apply, but I also need the first 14 lines and the last 3 lines of the file. I wanted to make sure that you had this information.

      Steveieb, I used your code but I get no results. I used your code as is, and the perl command line window got no output. If I define the output file the file gets created with no content. On a guess I changed the input file name to a nonexistent file and I got the same results, and no errors. Please pardon my noobness, and I hope that you can help :)

      UPDATED: Here is what I have at the moment as I am trying to output the results to another file (the .pl file sits in the same directory as the input/output files):

      use warnings;
use strict;

#Note that this script throws errors when pull file paths are defined.
#Must be run from the path that the input/output files exist.

open my $fhi, '<', 'cr835.txt' or die "$!";
open my $fho, '>', 'cr_output.txt' or die "$!";

#Prints the first 14 lines to the output file
while(<>) {
  1 .. 14 ? print : last;
}

#Prints content starting with LX* and ending with CAS*
#but only if 00003 exists
{
    local $/ = 'CAS*';
    while (<$fhi>){
        print $fho if /LX\*.*(?=00003$)/s;
    }
}

#Prints the last 3 lines of the file
while (<F>) {
    $. < $lines - 3 and print while <F>
}

close $fhi;
close $fho;

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[d/l]

        $lines is not defined. The /m is required for the $ in 00003$. What file do you think it is reading the first 14 lines from?

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