Although somewhat detached from the original bug description, I
encountered a similar issue with git (1.9.1, 2.11.0) while using trusty
on WSL. I received the following error message when running 'git help':
warning: failed to exec 'man': Is a directory
fatal: no man viewer handled the request
man-db should be at most a recommendation because (1) it’s only
documentation and (2) the man viewer is configurable. However, it is
not normal for packages to either depend or recommend man-db. It’s in
ubuntu-standard, and if you don’t have ubuntu-standard there might be a
reason you don’t want
