use strict;
use warnings;

my $str = "a history of u.s. coast guard aviation.  M.C. Esher";

$str =~ s/(?<=\W\w)\.//g;

print $str, "\n";

##</code><code>##

# Remove periods and capitalize, so we have US instead of us.
$str =~ s/(?<=\W)(\w)\./\U$1/g;