Well, there are ~12,000 gems(rubygems.org/ says 12,442) $ gem list -r | wc -l 12202 Of which ~6,000 have underscores or dashes in their name $ gem list -r | grep -e '-|' -c 6022 dash has more than than underscore $ gem list -r | grep -c '-' 3570 $ gem list -r | grep -c '' 2734 and there are even a few with both $ gem list -r | grep '_' | grep '-' -c 282
Dash has a fair lead, and is also domain-name friendly. So, for my next project, I'll probably use it as the spacer in my gem's name.