my $string;
$string = 'lasdufaner%.alsdfi,' x 100;
# $string = 'freddy\'s wife wilma, ' x 100;

my $max  = 100;

if ( $string and length $string > $max ){
   $string = substr( $string, 0, $max);
   my ($tmp) = $string =~ /(.+)\s.*?$/; # last space if possible
   $tmp or ($tmp) = $string =~ /(.+)\W.*?$/; # bust on last non-word
   $tmp and $string = $tmp;
   print $string
}