Re: zsh portable script

[Atom Smasher <atom@smasher.org>]

On Tue, 13 Jul 2010, Benjamin R. Haskell wrote:

> But, I don't recall ever needing root to read the battery status.  (In 
> the /proc/acpi subsystem that you're using, 
> /proc/acpi/battery/BAT{0,1}/{info,state} are chmod 0444 on my laptop and 
> netbook; same for the /sys/class/ stuff I used above.)  And on my 
> FreeBSD webhost where I have pretty resticted access, I seem to be able 
> to grab a lot of hardware-related info via sysctl.
==============

from what i've seen, linux permissions to anything in /proc depend on the 
distro, but the same *info* is available to anyone with local access on a 
bsd box via sysctl.

i'm more familiar with freebsd than linux. are you saying that 
/sys/class/power_supply/BAT0/charge_* will be readable when 
/proc/acpi/battery/BAT0/* isn't? if that's the case, i'll update the 
script.


> Are permissions the reason you suggest running it under cron? Otherwise, 
> why not just regenerate in precmd()?
==================

on my bsd laptop i always have at least one mrxvt with ten shells open. it 
seems to make sense to just have root get the info once per minute and let 
the shells read it from a file, than have a bunch of shells all invoking 
sysctl and all figuring out about the battery.

i suppose it can be done without privileges, and it shouldn't burden the 
machine; then i suppose it might make sense to get rid of the battery 
script and put the logic into precmd. i suppose the worst case is a 
hundred or so shells all working it out for themselves... that shouldn't 
cause any problems... except if the machine is bogged down and it takes 
that much longer to wait for a prompt that's hung while something it needs 
to generate a battery notice is blocked (although that risk is probably 
there already with the load monitor). i might be able to add a short 
timeout, in which case it will just skip it... something to think about, i 
guess.


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