USE variable question

[Athernigy]

If I am understanding correctly, USE var is for manpages?

If above is correct, how can I do so that no manpages are installed?
Do I need to add a minus infront of all possible variables and put it in the 'USE="..."' variable?

Thank you.

[kimchi_sg]

[Athernigy]

What is USE variable for then?

I don't want manpages because there is no reason to waste disk space on a server. All manpages are available online anyways.

I don't think I am understanding what the USE variable is for???

Thanks.

[kimchi_sg]

[Athernigy]

"It is for controlling which optional parts of a program to include during installation.

Only 100% optional features of a program can be controlled with USE flags. "

Yes, this is what it said in the manual also, but how does it work exactly?

Looking in /usr/portage/profiles/use.desc all the tags in there seem to be for some sort of support. If this isn't for manpages, what support is it for?

Are all of these installed by default? If I wrote USE tag, does it assume no support for all packages or all support or some. I guess I wanna figure out what is best method of customizing. Do I need to add a - infront of all items I don't want, and put the names of the items I do want?

First doc for 'man emerge' on google:
http://gentoo-wiki.com/MAN_emerge

Also, if anything I can store manpages on a personal laptop. I still don't think there is any reason to have anything but the bare minimum on a server.

[falcon_za]

Let's say first things first. I will say very obvious things, but since I am not sure where you got it wrong, and what your knowledge level, better go from the begginning.

USE variable has an influence on how a program is compiled (ie: translated from human written/readable program to computer executable program). In some case, the original developper planned different possibilities for compilations, different options. if you compile this way, you will have support for feature A, if you compile that way, you wont. Sometimes, the developper didn't put any options, and there is only one way to build the program.

When there are options, USE flag is the way to tell the gentoo software installer (portage, via the command emerge) that which one you want to compile in. it may also have an influence on the dependecies, ie: what must be installed in addition to you program to let it work properly.

for example, a music player could be sensitive to the use flag "mp3" if it is there, it will install an mp3 decoder, and compile in such a way it can use it. If you know you won't need mp3, you can set -mp3, and it will remove this optional support. but if you install an mp3 encodin software, it won't pay attention to the useflag mp3, because for it, is it a core functionality, not an option.

Some use flags are defined for a large range of software (support for gnome, kde, X, dvd, ipv6....), some are specific to one package (activate/disactivate the mail client in mozzila, for instance)

by seting some use flags and unsetting others, you can specify to a quite fine level what kind of functionality you want your system to support. by unsetting everything you know you wont need, you get a system with less unneeded software install, thus saving disk space, possibly some speed. It is also nice to note that if there is a security bug in something you don't need, you can more easily let it out of you system thank to use flags.

Most binary distros compile with maximum options activated, so you won't miss anything, but this leed to a more-than-you-need system, with all the space waste and security risks implied.

I hope I have been clear enough, and not too dumb.

About having man pages on a server or not, I'd say keep them. they are not that big, they are not a program, so there is no security risk, they don't comsume processor unless you read them, and they might come in handy. your internet connexion my be down for a while. maybe by your fault. How to fix it if you don't have the doc? but if you really don't want them you can allway manualy remove the directory where they are stored. Not that i would do it, but you can.

[Athernigy]

"If you want to conserve disk space, just choose what to install very carefully. Also, use as few USE flags as possible to minimise program linkage to unnecessary libraries. And do not use genkernel if possible, compile the kernel manually and select only the options that you really need."

I am trying to figure out how I can start with a clean state, where there are no USE Flags ... and maybe I can add on to that?

I don't think I am explaining myself well enough ...


"If you are setting up a webserver, you may be interested in the discussion on "what USE flags to use?" here: https://forums.gentoo.org/viewtopic-t-316212.html"


Not that simple, because I am setting up a few machines. Some will have apache ... some wont, some will have postgre some wont.

I'd rather get a good understanding of what it is and how it works then use a generic version.

[Athernigy]

[kimchi_sg]

[Athernigy]

[kimchi_sg]

[Athernigy]

[kimchi_sg]

[Athernigy]

Okay, so the USE flag will only be used strictly after the installation of gentoo is complete? (ie. meaning it isn't used within the installation of any parts of gentoo, the kernel, etc.)

[kimchi_sg]

[Athernigy]

Thx.

Do I need to explicitly turn each USE flag on or off? Meaning do I have to do mp3 or -mp3 (and so on for each flag)? ... or are some flags set by default, how can I find out which is set as what?

[kimchi_sg]

[tuam]

[wjholden]

[kimchi_sg]