Hi Colin,

I find this quite intriguing.  Using a space in place of an underscore
in the name of a manual page seems to work, but using two seems to not
work.  This seems inconsistent.  I'd say this should either work for any
and/or all spaces, or for none of them.

	$ man -aw proc_sys_fs_inotify
	/usr/local/man/man5/proc_sys_fs_inotify.5
	$ man -aw proc sys_fs_inotify
	/usr/local/man/man5/proc_sys_fs_inotify.5
	$ man -aw proc_sys fs_inotify
	/usr/local/man/man5/proc_sys_fs_inotify.5
	$ man -aw proc_sys_fs inotify
	/usr/local/man/man5/proc_sys_fs_inotify.5
	$ man -aw proc sys fs_inotify
	/usr/local/man/man5/proc_sys.5
	/usr/share/man/man5/proc_sys.5.gz
	No manual entry for fs_inotify
	$ man -aw proc sys_fs inotify
	/usr/local/man/man5/proc_sys_fs.5
	/usr/share/man/man5/proc_sys_fs.5.gz
	/usr/local/man/man7/inotify.7
	/usr/share/man/man7/inotify.7.gz
	$ man -aw proc_sys fs inotify
	/usr/local/man/man5/proc_sys_fs.5
	/usr/share/man/man5/proc_sys_fs.5.gz
	/usr/local/man/man7/inotify.7
	/usr/share/man/man7/inotify.7.gz
	$ man -aw proc sys fs inotify
	/usr/local/man/man5/proc_sys.5
	/usr/share/man/man5/proc_sys.5.gz
	/usr/local/share/man/man5/filesystems.5
	/usr/share/man/man5/filesystems.5.gz
	/usr/local/man/man7/inotify.7
	/usr/share/man/man7/inotify.7.gz

The same thing happens with dashes:

	$ man -aw user-session-keyring
	/usr/local/man/man7/user-session-keyring.7
	/usr/share/man/man7/user-session-keyring.7.gz
	$ man -aw user session-keyring
	/usr/local/man/man7/user-session-keyring.7
	/usr/share/man/man7/user-session-keyring.7.gz
	$ man -aw user-session keyring
	/usr/local/man/man7/user-session-keyring.7
	/usr/share/man/man7/user-session-keyring.7.gz
	$ man -aw user session keyring
	No manual entry for user
	/usr/local/man/man7/session-keyring.7
	/usr/share/man/man7/session-keyring.7.gz

And also with combinations:

	alx@devuan:~/src/linux/man-pages/man-pages/contrib$ man -aw proc_sysrq-trigger
	/usr/local/man/man5/proc_sysrq-trigger.5
	/usr/share/man/man5/proc_sysrq-trigger.5.gz
	alx@devuan:~/src/linux/man-pages/man-pages/contrib$ man -aw proc sysrq-trigger
	/usr/local/man/man5/proc_sysrq-trigger.5
	/usr/share/man/man5/proc_sysrq-trigger.5.gz
	alx@devuan:~/src/linux/man-pages/man-pages/contrib$ man -aw proc_sysrq trigger
	/usr/local/man/man5/proc_sysrq-trigger.5
	/usr/share/man/man5/proc_sysrq-trigger.5.gz
	alx@devuan:~/src/linux/man-pages/man-pages/contrib$ man -aw proc sysrq trigger
	/usr/local/man/man5/proc.5
	/usr/share/man/man5/proc.5.gz
	No manual entry for sysrq
	No manual entry for trigger

The (one) space is well-known to work, and helps find documentation for
things like 'git diff' as 'man git diff', so that behavior should stay.
I suspect we also want to make it work for more than one space, though.
Or are there any important issues with handling more than one space?

Here's the version of man-db I have installed (Devuan unstable):

	$ dpkg -l man-db | tail -n1
	ii  man-db   2.13.1-1   amd64          tools for reading manual pages


Have a lovely night!
Alex

-- 
<https://www.alejandro-colomar.es>