wordboundTest();

sub wordboundTest {
 print wordbound("rmi.port=1234", "port", "nport"),"\n"; 
 print wordbound("rmi.port=1234", "Port", "nport"),"\n"; 
 print wordbound("rmi.port=1234", "ort", "nport"),"\n"; 
 print wordbound("rmi.port=1234", "i.port", "nport"),"\n"; 
 print wordbound("s/\\brmi\\b/RMI", "\\brmi\\b","RMI"), "\n";
}
sub wordbound {
  my ($line, $fromword, $to)=@_;
  #print "$line:$fromword:$to\n";
  #my $regular=quotemeta($fromword);
  my $matched=$line =~ s/\b\Q$regular\E\b/$to/g;
  if ($matched) {
    #print "$line\n";
    return $line;
  } else {
    return undef;
  }
}