The nanoc command-line interface uniformly uses hyphens for multi-word commands and options (create-site, show-plugins, etc.). Names given to the check command, however, use underscores (external_links, internal_links, mixed_content), which is inconsistent with the rest of the command-line API and increases cognitive load since one has to remember when to use hyphens and when to use underscores.
Implementation details aside, it might be helpful for nanoc check to accept hyphenated names, as well. (Listing names in hyphenated, rather than underscore, form would be nice too.)
Migrated rom #1090: