#!/usr/bin/perl

use strict;
use warnings;

my %words;

while (<>) {
  chomp($_ = lc);
  for (/\b\w+(?:'\w+)?\b/g) {
    next unless length > 3;
    my $order = join "", sort split //;
    $words{substr($_, 0, 1) . substr($_, -1, 1)}{$order}{$_} = 1;
  }
}

for my $k (sort keys %words) {
  my @multi = grep keys %{ $words{$k}{$_} } > 1, keys %{ $words{$k} } or next;  

  print "$k\n";
  for my $o (sort @multi) {
    my $w = $words{$k}{$o};
    print "  $o (" . keys(%$w) . ") @{[ keys %$w ]}\n";
  }
}