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On Thu, Jul 24, 2008 at 11:01 PM, Alan Mackenzie <acm@×××.de> wrote: |
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> |
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> |
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> I'm still very confused by profiles, though I obviously need to get to |
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> grips with them. What is a profile, _EXACTLY_? Where in the |
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> documentation can I find a description which says something like ".... a |
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> profile is a directory which contains the following files" and then lists |
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> them? There are lots of instructions to "set foobar in your profile", |
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> but the only description I've found so far just says "A profile is a |
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> building block for any Gentoo system" in the Gentoo Linux x86 Handbook, |
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> and then goes on to describe what a profile _does_ in abstract terms but |
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> not what it _is_ in terms of directories and files. That section says |
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> that I "have" the option of choosing another profile too, but not how to |
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> recognise a profile from a random directory or file. I don't understand |
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> how to select it. |
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A profile is a starting point for a gentoo install, and a set of defaults. |
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They are stored in $PORTDIR/profiles in a sensible hierarchical structure |
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and contain information like default USE flags, the full collection of |
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packages |
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that make up the system set etc etc. Profiles are obviously tweaked to suit |
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the average needs of categories of users, so there are desktop and server |
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profiles. They also cascade which is to say a profile inherits common stuff |
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from it's parent profile (which minimizes the admin hassle of adding the |
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same new stuff to every profile in existence) |
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Setting a profile is a simply matter of creating the symlink as you have |
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done here: |
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> |
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> |
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> I have a link |
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> |
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> /etc/make.profile -> /usr/portage/profiles/default/linux/x86/2008.0 |
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> |
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> , set up as suggested in the handbook. Is .../2008.0 my profile? |
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Yes, this means the profile you are using is the 2008.0 profile for x86 |
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> Is |
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> this valid? There doesn't appear to be anything of substance there. |
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If you navigate to the directory the symlink points to, you will find a |
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bunch of files. |
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These define the profile, and the names and contents are by and large quite |
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self-explanatory |
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> |
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> On the other hand the handbook says a few lines lowere, I should select a |
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> profile with: |
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> |
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> # ln -snf /usr/portage/profiles/<profile name> /etc/make.profile. |
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> |
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> In that directory, /usr/portage/profiles, there are both subdirectories |
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> (e.g. default-linux) and some files (e.g., make.defaults, |
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> packages.builds). Is "<profile name>" one of the directories rather than |
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> a file? It looks almost as though there's some sort of hierarchical |
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> inheritance going on. |
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Correct. The profile is a directory name |
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> Please tell me that this is clearly explained somewhere. |
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The handbook tells you all you need to know actually. Perhaps you are |
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reading |
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more into the matter than is actually there. |
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As I said above, a profile is nothing more than the definition of a starting |
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point |
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and a bunch of defaults that are applied if you don't explicitly state what |
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you want. |
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When you installed gentoo, you might have run 'emerge -e system' which would |
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have built a whole bunch of stuff (toolchain, coreutils, etc, etc) with a |
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bunch of |
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USE flags already enabled. That info came out of the profile. When you edit |
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make.conf |
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to better suit YOUR needs, that edit overrides the profile. You hardly ever |
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need to |
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change your profile unless it is many years old and has been removed from |
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portage. |
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The longer you use gentoo, the more specific your system becomes to what you |
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want, |
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and the further away it moves from the default. |
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What you do do, is edit make.conf and the various files in /etc/portage/* to |
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get what you want. |
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Don't go editing the profile directories, your changes simply get nuked with |
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the next |
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'emerge --sync'. Only edit the user files, which are documented in 'man 5 |
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portage' |
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In four years of using gentoo I have had to mess around with profiles |
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exactly once. |
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I was building a highly customized install that is quite radically different |
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from the norm, |
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so I created a custom profile inherited from the one that was closest to |
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what I wanted, |
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stored it somewhere out of the way and pointed portage to it. In all other |
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cases I just used |
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what was there. I couldn;t even tell you right now what profile my home |
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machine is using :-) |
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Hope this help clear up the situation for you. |
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-- |
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Alan McKinnon |
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alan.mckinnon@×××××.com |
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