#! /usr/bin/perl
use strict;
use warnings;

my $data = lc "howdoesonehandlethissensibly";
#my $data ='thesuperuserwascalledderekuser';

my %foundwords;
my $position;
while (<>) {
    chomp;
    next unless length>2; # remove 1 and 2 letter words
    $position = 0;
    while (index($data,lc $_, $position) >= 0) {
        my $found = index($data, lc $_, $position);
        push @{$foundwords{$found}}, lc $_;
        $position = $found + 1;
    }
}

# Print the word combinations
printwords('', -1);
sub printwords
{
    my $string = shift;
    my $position = shift;
    
    while (++$position < length $data) {
        if (exists $foundwords{$position}) {
            foreach my $word (sort {length $a <=> length $b} @{$foundw
+ords{$position}}) {
                printwords (join(' ', $string, $word), $position + len
+gth($word) -1);
            }
            last;
        }
    }
    print "$string\n" if $position == length $data;
}
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