in reply to regexp help -- grab almost a whole string

my $circuit_id = ( $if_descr =~ /([^.]*)(?:\.(.*))?/
   ? $1 . (defined($2) ? $2 : '')
   : undef
);

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But it can be shortened to 
(my $circuit_id = $if_descr) =~ s/\.//;

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In Section Seekers of Perl Wisdom