Between Two Regex: Find the text between two lines that match regexes.

between_two_regex

#!/usr/bin/env perl

use strict;
use warnings;
use Carp;
use v5.10;
use constant FALSE => 1==0;
use constant TRUE => not FALSE;

# Given two regex that match a start and end line, return blocks of
# text between lines like that.
#
# Invoke it like this:
#
#     ./between_two_regex 'first line.' 'last line.' data_for_test.txt

$#ARGV == 2 or die "Error: You must pass two regex as arguments!";

my $start_line=shift;

my $end_line=shift;

my $start_line_seen=FALSE;
my $end_line_seen=FALSE;

while(<>){

  m/$start_line/
    and $start_line_seen=TRUE
    and $end_line_seen=FALSE;

  m/$end_line/
    and $end_line_seen=TRUE
    and $start_line_seen=FALSE;

  $start_line_seen
    and print qq{'$ARGV': $.: $_};

} continue {

  # Reset $. at the end of each file
    close ARGV if eof;
}

data_for_test.txt

This is the first line.
a
b
c
This is the last line.

This text does not get captured.

This is the first line.
1
2
3
This is the last line.

This is some other text that doesn't match.

This is the first line.
A
B
C
This is the last line.