knoppix@Microknoppix:/media/sda1/perl/Monks$ perl -E '
> $str = q{6 - 10, 14 - 17, 19};
> $str =~ s{-}{..}g;
> say $str;'
6 .. 10, 14 .. 17, 19
knoppix@Microknoppix:/media/sda1/perl/Monks$