c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'CCHHHCHHCHC';
 print qq{'$s'};
 ;;
 $s =~ s/(\w) (?!\1). \1/$1$1$1/xgi;
 print qq{'$s'};
"
'CCHHHCHHCHC'
'CCHHHHHHHHC'

##</code><code>##

c:\@Work\Perl\monks\flappygoat>perl -wMstrict -le
"my $s = qq{\1\x01\o{001}\cA};
 print 'match' if $s =~ /[^\1]/;
 print 'count: ', $s =~ tr/\1//;
"
count: 4