[gentoo-user] rc script opacity

[gentoo-user] rc script opacity

[Philip Webb]

The script  /etc/conf.d/rc  contains the following lines :

  # RC_USE_CONFIG_PROFILE allows you to have different /etc/conf.d files
  # based on your runlevel - if a conf.d file for your profile does not exist
  # then we try and use the default one.
  # To enable runlevel selection at boot, append "softlevel=foobar" to your
  # kernel line to change to the foobar runlevel. Or "rc foobar" at the command
  # prompt.

  RC_USE_CONFIG_PROFILE="yes"

Can anyone explain what this means ?

Eg how do you define different  conf.d  files ?
Why does it suddenly talk about enabling runlevel selection at boot ?
What does it mean by "kernel line" ?  What is the "command prompt" here ?

The kernel doc for parameters has nothing about "softlevel".

Have I had too long a day or is this something which needs updating ?

-- 
========================,,============================================
SUPPORT     ___________//___,  Philip Webb : purslow@chass.utoronto.ca
ELECTRIC   /] [] [] [] [] []|  Centre for Urban & Community Studies
TRANSIT    `-O----------O---'  University of Toronto
-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] rc script opacity

[Holly Bostick]

Philip Webb schreef:
> The script  /etc/conf.d/rc  contains the following lines :
> 
> # RC_USE_CONFIG_PROFILE allows you to have different /etc/conf.d 
> files # based on your runlevel - if a conf.d file for your profile 
> does not exist # then we try and use the default one. # To enable 
> runlevel selection at boot, append "softlevel=foobar" to your # 
> kernel line to change to the foobar runlevel. Or "rc foobar" at the 
> command # prompt.
> 
> RC_USE_CONFIG_PROFILE="yes"
> 
> Can anyone explain what this means ?
> 
> Eg how do you define different  conf.d  files ? Why does it suddenly 
> talk about enabling runlevel selection at boot ? What does it mean by
>  "kernel line" ?  What is the "command prompt" here ?

Some people,. for example, laptop users, may boot their computer under
varying conditions.

A laptop may be booted on "the street", in which case there is no network
available.

Or it may be booted when docked, in which case there may be a network
available (if you're at home or work), or there may be a network
available that only has limited capacity (if you're in a hotel or an
internet cafe).

So it can be useful to be able to create a profile for varying but known
conditions under which the computer may be booted (there's no point in
starting network services in the event that you know you're not
connected to a network, but there's also no point in making 'no network
startup' the only possible setting, because then it's a PITA to get the
network started on those occasions that you are connected to a network
at boot).

Therefore, you can have profiles for 'home' (which would start the
network with your known LAN settings), 'out' (which would not start the
network at all, because you're in a park or on a client's site), or
'away' (which would start a network, but detect the settings manually,
because you're in a hotel on a business trip, and you don't know their
settings offhand).

The 'kernel line' being referred to is the line in your bootloader that
specifies the kernel and parameters that should be called when you
select that entry in the bootloader menu.

The 'command prompt' referred to is probably the bootloader command
prompt (I don't remember how LiLO does it, but in GRUB you can edit menu
entries on the fly and boot from the edited entry).

I don't know how you define rc.conf files for softlevels, since I don't
need softlevels, but I have seen discussions of this on the list in the
past. There's probably a Wiki entry on the subject as well.

But if you don't boot your computer under varying conditions, you don't
really
need to worry about it anyway.

HTH,
Holly
-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] rc script opacity

[Neil Bothwick]

[-- Attachment #1: Type: text/plain, Size: 1034 bytes --]

On Wed, 31 Aug 2005 16:23:33 +0200, Holly Bostick wrote:

> The 'command prompt' referred to is probably the bootloader command
> prompt (I don't remember how LiLO does it, but in GRUB you can edit menu
> entries on the fly and boot from the edited entry).

It's the normal (root) shell prompt. You can use the rc command to switch
runlevels after booting. To use your example, you're using your laptop
on the train, with the out runlevel because there's no network. Then you
arrive at home or the office and want to switch to the relevant profile
and start the services, so you run "rc home".
 
> I don't know how you define rc.conf files for softlevels, since I don't
> need softlevels, but I have seen discussions of this on the list in the
> past. There's probably a Wiki entry on the subject as well.

There doesn't appear to be anything on the wiki, which is a shame,
because this looks a useful feature.


-- 
Neil Bothwick

If you're not part of the solution, you're part of the precipitate. *
Wright

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: [gentoo-user] rc script opacity

[Holly Bostick]

Neil Bothwick schreef:
> On Wed, 31 Aug 2005 16:23:33 +0200, Holly Bostick wrote:
> 
> 
>> The 'command prompt' referred to is probably the bootloader command
>>  prompt (I don't remember how LiLO does it, but in GRUB you can
>> edit menu entries on the fly and boot from the edited entry).
> 
> 
> It's the normal (root) shell prompt. You can use the rc command to
> switch runlevels after booting. To use your example, you're using
> your laptop on the train, with the out runlevel because there's no
> network. Then you arrive at home or the office and want to switch to
> the relevant profile and start the services, so you run "rc home".

oh, DUH! (What is wrong with my brain??) Now I see what devs (and you)
mean when they say that Gentoo is heavily customized. If I was still
running Slack, I would have immediately realized the similarity between
running 'rc softlevel' in the console, and running 'init 3' in the
console (so I would have remembered that it's perfectly possible and
feasible to change runlevels from the command prompt). But clearly, 'the
Gentoo way' is slowly erasing 'the Linux way' from my mind, not
dissimilar to the way that I often now can remember the word for a
concept easier in Dutch than I can in English.

It's perfectly normal, and not really a bad thing, but it's disturbing
when it pops up in your face like that.

> 
> 
>> I don't know how you define rc.conf files for softlevels, since I
>> don't need softlevels, but I have seen discussions of this on the
>> list in the past. There's probably a Wiki entry on the subject as
>> well.
> 
> 
> There doesn't appear to be anything on the wiki, which is a shame, 
> because this looks a useful feature.

Volunteers? :)

But isn't it in the docs somewhere, or has that not yet been written
either (that would be odd, especially given all the updates that the
Documentation team has been doing lately)?

Holly
-- 
gentoo-user@gentoo.org mailing list