Re: bin/47701: apropos doesn't work

[Abhinav Upadhyay <er.abhinav.upadhyay%gmail.com@localhost>]

The following reply was made to PR bin/47701; it has been noted by GNATS.

From: Abhinav Upadhyay <er.abhinav.upadhyay%gmail.com@localhost>
To: NetBSD GNATS <gnats-bugs%netbsd.org@localhost>
Cc: gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: bin/47701: apropos doesn't work
Date: Fri, 29 Mar 2013 01:36:36 +0530

 Hi,
 
 On Thu, Mar 28, 2013 at 9:05 AM,  <root%garbled.net@localhost> wrote:
 > The new apropos in 6, doesn't seem to give reasonable results.  While trying
 > to find the usbdevs(8) command, I ran:
 > apropos -C usb
 >
 > and got:
 > alcyone# apropos -C usb
 > usb (4) Universal Serial Bus driver
 > usbhid (3) USB HID access routines
 > cdce (4)   USB Communication Device Class Ethernet driver
 > ulpt (4)   USB printer support
 > uep (4) USB eGalax Touchpanel
 > ukbd (4)   USB keyboard support
 > cue (4) CATC USB-EL1201A USB Ethernet driver
 > uts (4) USB generic touchscreens
 > umodem (4) USB modem support
 > ucom (4)   USB tty support
 >
 > If I want to find usbdevs, apparently I have to do -C8 ??
 
 As others have mentioned, the new apropos displays only the top 10
 results, which some times might not be enough to get the expected
 results.
 There is a -n option as well to specify exactly how many results you
 want to see.
 
 As far as usbdevs(8) not appearing in the top results is concerned,
 its a hard problem to figure out what exactly the user is looking for
 :)
 But on a more serious note, apropos uses term frequency to compute the
 rank of matching man pages in search results (apart from few other
 factors).  In case of usbdevs(8) man page, its length is too short
 (which should not be too big a contributing factor, since the
 algorithm tries to normalize it). But more importantly, the keywords
 usbdevs and usb are treated as two different keywords by apropos,
 which means an occurrence of usbdevs in the man page does not
 contribute towards a higher rank.
 
 I will try to experiment, if the ranking algorithm can be tweaked in
 some way to improve behaviour in such cases.
 
 >
 > Aside from that, I find the new format of man -k to be obnoxious.  Can we
 > revert to the historical display, or maybe make it sensitive to an 
 > environment
 > var, like OLDMAN=YES ? :)
 
 Not possible to get the exact same behaviour as the old apropos, but
 it is still possible to just perform search in the NAME section (like
 the old apropos).  You can disable indexing of complete content of man
 pages by using makemandb -lf, after which apropos automatically will
 search in the NAME section. However, if there is a demand, I can add
 an option to apropos itself to just search in the NAME section.
 
 --
 Abhinav