abcdecgf
has 7 unique letters.

A single regexp would be too convoluted I guess (I say that only because such a regexp is beyond my skills :-) update: or laziness :-) 

#!/usr/bin/perl -nl
if (length == 8) {
  $c = substr ($_, 2, 1);
  if (substr ($_, 5, 1) eq $c) {
    my %h;
    @h{split//,$_} = (1) x 8;
    print if keys %h == 7; 
  }
}
__END__
perl match.pl /usr/share/dict/words
Abednego
abscised
Acadians
Acadia's
Acalia's
acerbest
Adaiha's
Adalia's
Adelbert

...

whirling
whisking
Wieche's
wielders
Winton's
worker's
writhing
Yahweh's
Yeargain
Ygerne's
Yorker's
Zarger's
Ziegfeld

[download]

update: changed to -nl to apply on /usr/share/dict/words

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re^3: Regex help by shmem
in thread Regex help by Anonymous Monk

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