#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper::Simple;

read DATA, my $text, 163; #<- manually grabbed size of DATA just for this example

my @matches = ($text =~ /red line.*?location\s+(\d+\.\d+\s+\d+\.\d+)/sg);
print Dumper(@matches);

__DATA__
A red line is found
at location 2.5 4.5
A Blue line is found
at location 2.6 4.5
A red line is found
at location 2.67 4.56
The red arc is found
at location 2.5 4.5