Many distros come with Ruby standard, it's not very big and I think it has a lot to recommend it over Python or Perl when it comes to lightweight scripting for sysadmins and day to day automation. I wouldn't necessarily pull it into an open source project where they weren't already present, but I would definitely choose it for personal use well before Python or Perl
Ubuntu, Debian, Arch, CentOS - none of these, as far as I know, ship with a Ruby interpreter by default. I’d like to be wrong, but I don’t think many do.
