Except it doesn't work: 
sub compare {
  (($_[0] ^ $_[1]) =~ tr/\0//c) < 2;
}

print((compare('abc', 'abcd') ? 'ok' : 'not ok'), "\n");

[download]
It should be 
sub compare {
   length $_[0] ==  length $_[1] && (($_[0] ^ $_[1]) =~ tr/\0//c) < 2;
}

[download]

In reply to Re^3: Tell whether two strings differ at only one position by ikegami
in thread Tell whether two strings differ at only one position by rg0now

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