use strict;
use warnings;


my $hardlimit = 100;
my $string = <<HERE;
This is a test string.  I'm going to force it to split on a word if it kills me.  Ok, supercalifragilisticexpialadocious.
HERE


if ( $string =~ m/^(.{1,$hardlimit})(?=\b)/ ) {
    print "Match: $1...\n";
print "Length: ", length $1, ".\n";
}

__OUTPUT__
Match: This is a test string.  I'm going to force it to split on a word if it k
ills me.  Ok, ...
Length: 86.