[mythtv-users] Device permissions

Rod Smith mythtv at rodsbooks.com
Fri Nov 20 22:54:11 UTC 2009

On Friday 20 November 2009 02:56:22 pm aaron wrote:
> I figured the easy fix would be to add a udev rule to set the
> permissions to 0666:
> root at myth:/etc/udev/rules.d# cat 11-ivtv.rules
> KERNEL=="video[0-9]+", NAME=="video%n", MODE=="0666"
> But this doesn't seem to do anything. Is the above correct? Should it work?

I realize you've solved your problem in another way, but I thought I'd point 
out for your own future reference and/or for the benefit of others that 
you've used the udev equality test operator (==) in at least one place where 
you should have used the assignment operator (=). Specifically, 
'MODE=="0666"' just tests to find device files with a mode of 0666 (at least, 
that's what the syntax says; I don't know if udev actually supports this 
test), but you almost certainly meant 'MODE="0666"' to have it set the mode 
to 0666. The same might be true of the NAME test, although that should only 
appear in the primary definition for the device. On most distributions you 
wouldn't edit this definition; instead, you'd create a new definition (in a 
file you create yourself) that just adds whatever symbolic links, ownership 
changes, permissions changes, etc., that you want to add. That way, the 
distribution's package management tools won't erase your changes when it 
upgrades your udev package (or whatever package has the default file). Many 
of Slackware's package management and system configuration procedures are 
different from those for most other Linux distributions, though, so I'm not 
sure if the general procedure of adding new, rather than editing existing, 
udev rules applies to Slackware.

FWIW, the MythTV wiki has a section on udev, with examples tailored to the 
sorts of things MythTV users often need to do with udev:


Disclaimer: I'm the creator and primary author of that wiki page, although 
others have added some sections.

Rod Smith

More information about the mythtv-users mailing list