use warnings;
use strict;
use Data::Dump::Streamer;

my $str = <<SNIPS;
Hello all, I am encountering some issue in trying to do the following in ksh88,
therefore I want to explore a smart perl approach, but my knowledge is limited,
can you help?
I have 2 files, the first (indexFile1) contains lines with start
offset and length for each record inside the second file, so just 2 numbers
separated by a space. ...
SNIPS

open my $recData, '<', \$str;

while (<DATA>) {
    chomp;

    my ($start, $len) = split;
    my $segment;

    seek $recData, $start, 0;
    read $recData, $segment, $len;
    print "$segment\n";
}

__DATA__
16 12
80 9
315 10

##</code><code>##

encountering
therefore
separated