my $word = 'match';
my $string = 'Hatch a plan to watch this RE match';
my @match_re;
for my $offset( 0..length($word)-1 ) {
    my $possibility = $word;
    # replace one char with . to match anything
    substr $possibility, $offset, 1, '.';
    push @match_re, $possibility; 
}
my $match_re = join '|', @match_re;
print "The match RE is qr/$match_re/\n";
$match_re = qr/($match_re)/;
my @matches = $string =~ m/$match_re/g;
print "Found @matches\n" if @matches;

__DATA__
The match RE is qr/.atch|m.tch|ma.ch|mat.h|matc./
Found Hatch watch match