Re: [gentoo-user] Two portage questions

[Alan Mackenzie <acm@muc.de>]

Hi, Alan.

On Sat, May 14, 2011 at 12:51:14PM +0200, Alan McKinnon wrote:
> Apparently, though unproven, at 12:31 on Saturday 14 May 2011, Alan Mackenzie 
> did opine thusly:

> > 1. Where is it specified what is in "system" in the same way that
> > "world" is in the file /var/lib/portage/world?

> That is defined in your system profile, not by you.

> /etc/make.profile is a symlink to something in $PORTDIR/profiles/ and that 
> defines the profile you are using. A profile is nothing more than a bunch of 
> files that define what your basic system consists of - things like minimum 
> packages to install, things that must not be installed, starting point for USE 
> flags, etc etc.

> Profiles are cascading, meaning that more specific profiles can include other 
> more general ones, defined in files called "parent". These contain paths to 
> other directories (which themselves can have parents), and the whole lots os 
> recursively traversed from the bottom up till all the branches dead-end. The 
> full complete set of data you get out of all that is your complete profile.

> The specific files that define the system set are called "packages"

OK.  Some of these directories have got three parents.  ;-)  The people
deciding what goes into the "packages"es must have very steady hands.

> > 2. How does emerge know which mutt to build when I do "emerge mutt"?
> > There are three candidate files in /usr/portage/mail-client/mutt, e.g.
> > mutt-1.5.21-r1.ebuild.

> It will pick the ebuild with the highest version number, modified by your 
> rules concerning ACCEPT_KEYWORDS=, unmasked and masked packages.

> If your system is set to stable (ACCEPT_KEYOWRDS=amd64 for example), it will 
> pick between mutt-1.5.20-r18 and mutt-1.5.21-r1 as those are both stable. 
> Usually it will be 1.5.21-r1 as that is the most recent version. Normally you 
> will find two or more stable versions for most packages. This is by design so 
> that if an update on a stable system by chance breaks something, you still 
> have an earlier version to fall back on should the need arise.

OK, I get it.

> If your system is set to unstable (ACCEPT_KEYOWRDS=~amd64 for example), it 
> will pick mutt-1.5.21-r2 as that version is unstable (displayed with a 
> ~ symbol next to it in output).

I think I'll leave the unstable stuff alone.

> Sometimes you get packages that are masked, indicated with [m] or [M]. These 
> are for lunatics to test, and there are rules concerning masking that you can 
> use to free these up for use (it's all in the man pages). Mutt does not have 
> any such packages but nvidia-drivers for example does. You must take explicit 
> steps to obtain the latest version. This is so that the odds of validly being 
> able to blame anyone at all when nvidia trashes your system are reduced to 
> exactly zero.

> Do you have eix installed? You should, great tool, and makes figuring all this 
> out a whole lot easier.

I've got it now.  I'll go and have a look at it's /usr/share/doc / man
page.

Thanks!

> -- 
> alan dot mckinnon at gmail dot com

-- 
Alan Mackenzie (Nuremberg, Germany).