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HenryPeters
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PostPosted: Sun Jun 02, 2013 5:28 pm    Post subject: handbook availability & uninstall questions, pre install Reply with quote

Hi,

In reading the Gentoo Handbook, I see that in "Portage Introduction" it says:

Quote:
Removing Software

When you want to remove a software package from your system, use emerge --unmerge. This will tell Portage to remove all files installed by that package from your system except the configuration files of that application if you have altered those after the installation. Leaving the configuration files allows you to continue working with the package if you ever decide to install it again.

However, a big warning applies: Portage will not check if the package you want to remove is required by another package. It will however warn you when you want to remove an important package that breaks your system if you unmerge it.


So my question is: At least my current flavor of Linux (Debian Squeeze) has the consideration (via Synaptic Package Manager) to let one know that certain dependencies will also be removed (though not necessarily show the implications for removal, one still has to know something about inter-dependencies). I consider this an especially troubling mater, as I am having a great time (sarcasam alert) just learning how to install, with out really understanding (experientially) what I will, or will not be installing. I have suffered enough wasted time in Debian with removing (as it turned out) critical files, doing this trying-out, & then because of various problems with try-out programs (etc.), uninstalling... with serious problems then ensuing (or possibly ensuing, because I hesitated, etc.).

So there may be a reasonable solution here, but so far, I have not found it.

The second question I have is (probably) easier to answer:

How does one have access on line, during the install point where one goes out of the install from (in my case, the LiveDVD), to that of the CPU?

Thanks very much!

Henry
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NeddySeagoon
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PostPosted: Sun Jun 02, 2013 5:54 pm    Post subject: Reply with quote

HenryPeters,

You can rip out any random package you like with emerge -C (--unmerge). As the message says, dependencies are your problem but you will get a waring if the package in the in @system set.
You may also use
Code:
emerge --depclean
to remove packages that are installed but no longer required, e.g. your removed the package that needs them or they have become orphans.

I don't think that there is any package you can remove that cannot be recovered one way or another.
You can certainly make your system unbootable but its very hard to do something that can't be fixed to Gentoo. e.g.
Code:
emerge --unmerge glibc
is a very bad thing to do. Recovering from it and other very bad things will take from a few minutes to a few hours and you will learn some things you cannot learn any other way :)
Anyway, thats outside the scope of this post.

--unmerge does not remove dependencies.

I don't understand your second question.
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HenryPeters
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PostPosted: Sun Jun 02, 2013 6:29 pm    Post subject: Reply with quote

NeddySeagoon wrote:
I don't understand your second question.


Thanks for reply Neddy; gives me more confidence to proceed :)

As to the "second question," In the handbook (ch. 1) it outlines the install process:

Quote:
How is the Installation Structured?

The Gentoo Installation can be seen as a 10-step procedure, corresponding to chapters 2 - 11. Every step results in a certain state:
[snip]
After step 4, your installation environment is prepared and you are ready to chroot into the new environment
After step 5, core packages, which are the same on all Gentoo installations, are installed
After step 6, you have compiled your Linux kernel
After step 7, you have written most of your Gentoo system configuration files
After step 8, necessary system tools (which you can choose from a nice list) are installed
After step 9, your choice of bootloader has been installed and configured and you are logged in into your new Gentoo installation
After step 10, your Gentoo Linux environment is ready to be explored

I assume one is going from what ever medium one uses to do the first steps... then after step 4, I'm guessing one is still in the terminal environment... but (probably obvious to many) is one still able to view the handbook, from as I said "in my case, the LiveDVD?" Or is there a way to view it from the terminal, or... (what?)? I'm going to need it (!), I have printed out some of the early chapters... Hoping I don't have to do this for the rest (i.e., where I may not be in a gui/desktop environment).

Hope that's clearer (but possibly a simpleminded question, sorry 'bout that)...

Henry
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NeddySeagoon
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PostPosted: Sun Jun 02, 2013 11:21 pm    Post subject: Reply with quote

HenryPeters,

In your case, you boot the liveDVD and open a root shell, which is just another window. You perform all of the install steps there.

You have all of the DVD facilities available in other windows. You could switch to a real virtual terminal but there is no need.

After Step 10 and you reboot into your own Gentoo, all it can do is build more software. There is no GUI, no Xorg.
Its just you and the shell. However, you can continue installing things while chrooted, or if you have another system, you can ssh in and install remotely, just like you were on the live DVD still. Even Windows will provides a ssh client. PuTTY is one of several.
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Computer users fall into two groups:-
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HenryPeters
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PostPosted: Mon Jun 03, 2013 12:28 am    Post subject: Reply with quote

NeddySeagoon wrote:
HenryPeters,

In your case, you boot the liveDVD and open a root shell, which is just another window. You perform all of the install steps there.

You have all of the DVD facilities available in other windows. You could switch to a real virtual terminal but there is no need.

After Step 10 and you reboot into your own Gentoo, all it can do is build more software. There is no GUI, no Xorg.
Its just you and the shell. However, you can continue installing things while chrooted, or if you have another system, you can ssh in and install remotely, just like you were on the live DVD still. Even Windows will provides a ssh client. PuTTY is one of several.


Thanks much again Neddy!

That gives me some better understanding. One thing more, here, I do not know about, having never done or used it: the 'ssh' command... Is there a link to some more detailed info, technical enough to actual use, by someone just learning this command, that you, or someone might point me toward? (I'm guessing I'll be more comfortable in the shell, but as the poet said; "How can you learn less?")

In appreciation,
Henry
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NeddySeagoon
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PostPosted: Mon Jun 03, 2013 6:37 pm    Post subject: Reply with quote

HenryPeters,

ssh comes in two parts, a server that listens for connections and a client that connects to the server.

On your Gentoo install, ssh (both parts) are provided in the stage3 but the server is not configured to start by default.
You fix this by adding sshd to your default runlevel or by starting the sshd service by hand.

This gets sshd listening for connections.
To be able to connect to the sshd server, (called a daemon) you need three pieces of information

A username that the server will accept
The password for the above username
The IP address of the server.

The default user on the system is root and you set the root password as a part of the install.
You discover the IP address with ifconfig
Code:
$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.100.20  netmask 255.255.255.0  broadcast 192.168.100.255


To connect to the above system the command would be
Code:
ssh root@192.168.100.20

It goes something like
Code:
$ ssh root@192.168.100.20
The authenticity of host '192.168.100.20 (192.168.100.20)' can't be established.
ECDSA key fingerprint is 80:9c:8b:6d:1d:9c:6d:53:f1:59:9e:1b:0d:4a:76:61.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.100.20' (ECDSA) to the list of known hosts.
Password:


There are a few gotchas. If you run sshd on the liveDVD, it will make new host keys every time it starts. The system you connect from will complain loudly about a man-in-the-middle attack because of the key change. It will also tell you how to fix it.

Allowing ssh access to the root user is a gaping security hole, so as soon as you can, install sudo and configure sshd to reject root logins.
It will still go through the motions, but the password will never succeed.

I mentioned above that Gentoo provides both a ssh client and a server. This means that if you start the server, you can ssh to yourself.
Thats of no practical value whatsoever but it demonstrates that the system works.

The liveDVD scrambles the root password at boot, so you need to set it every boot so you know what it is.
Get a root shell and issue the passwd command.

Further reading
Code:
man ssh
man passwd
actually, that will make your eyes glaze over but they are useful references.
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Computer users fall into two groups:-
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HenryPeters
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PostPosted: Fri Jun 07, 2013 12:56 am    Post subject: Reply with quote

NeddySeagoon wrote:
HenryPeters,
Further reading
Code:
man ssh
man passwd
actually, that will make your eyes glaze over but they are useful references.


Eyes glazed! :roll: :) But more seriously, I'm at another stage... I did the install... but a previous earlier try with another OS (via Knoppix liveDVD), put some version of GRUB on my FIRST hd, where I boot Windows XP; bad news! So then, though, after several tries with GENTOO LiveDVD, finally got a (possible) install using the genkernel... I must have also installed the GRUB (w/ GENTOO) probably on the wrong hd (the first, as mentioned above), & only got my boot into Windows back after I found a good description on how to make a fix on the Windows MBR, via the Win XP install disk... (last night).

So my question now is (something like) can I \ do I remove/uninstall GRUB from my (possibly) working install of GENTOO (to get it to (hopefully) booting)? Or need I, or should I just do a complete new install... (one thing, my install of GENTOO is on my second hd, everything that I read about GRUB, seems to say that it installs it on the first hd, & when I did a 'ls' in GRUB rescue (which was all I had functioning, aside from the liveDVDs), I get, as the naming by GRUB (something like):
Quote:
'(hd0)(hd0,msdos2) (hd0,msdos1) (hd1,)(hd1,msdos3)(hd1,msdos2)(hd1,msdos1)
<--- this order (backward) & the msdosx labels rather confuse me, though the partitions do correspond correctly to what it is.

Any suggestions as to how I might proceed would be appreciated. & if all this seems too far afield from my original question, will be glad to move it to another new topic... just let me know if you might. THANKS.

Henry

P.s., I do believe, my previous Linux Debian Squeeze, I installed GRUB on the MBR of the second hd, it was partitioned in two parts, the first was formatted with NTFS (as a storage space, not the OS), for my XP OS, & second part. was ext3 (& now, I followed as exactly as I could the examples of the handbook as seemed relevant). Any way, GRUB worked great, then. & one other possibly relevant fact is that I am now using the entire second hd (500GiB) for GENTOO.
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PostPosted: Sun Jun 09, 2013 10:02 am    Post subject: Reply with quote

You get to choose where you install grub.

You have 3 choices. The MBR of your first HDD. You may not want to do that as your Windows bootloader is there.
The MBR of your second HDD, this is a good idea as you can tell your BIOS to load it.
The first partition of your second HDD is also a possibility but less useful as your BIOS cannot read it.

Conventional wisdom is that you put GRUB on the MBR of your 2nd HDD and tell your BIOS to boot from there.

You will learn the following process quite well, it how you regain control of your gentoo, when it won't boot.
Feel free to restore the Windows bootloader any time, this process will not be affected.

Boot the liveDVD, open a root shell and do all of the filesystem mounting steps from the handbook.
Do not make any partitions, do not make any filesystems. Yours are already there intact.
Do not forget /proc and /dev
Do the chroot steps, including env-update, source /etc/profile.

You are now back in your gentoo as if you had never left it.
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PostPosted: Sun Jun 09, 2013 10:35 am    Post subject: Reply with quote

I tend to use Gentoo on laptops, which have fairly neurotic MBRs (recovery
partitions and so on) which I don't like to tinker with. So I boot Gentoo
with the sequence MBR => Windows => Grub => Gentoo. It takes ten
seconds longer, but it seems worthwhile - Windows has no clue that
Linux exists, really, and continues on its way without fuss, and once
I've installed Grub 1.x on it's own partition I never have to touch it
again except to edit grub.conf

Look up Windows boot loader and BCDEdit. ISTR that XP, if you are
using that, has a text configuration file that you can edit by hand.

Will
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HenryPeters
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PostPosted: Sun Jun 09, 2013 2:47 pm    Post subject: Reply with quote

Thanks for reply & info, Neddy & cwr, do appreciate it...

Yes, I figured out how to chroot again... & now in a rather different place... I decided that I, accordingly, had better post a new (GRUB) question, I did so at

http://forums.gentoo.org/viewtopic-t-961532-highlight-.html

The short of it is, I got the Gentoo Grub loading... it recognizes my OS's (Gentoo/XP), but get 'file not found' error msgs when I try booting any of them... I tried editing the boot configuration in Gentoo Grub, to no avail ( I may need to do more, like w/ my .config file, as more or less stated in the handbook ??? & still rather confused, by the nomenclature of hd by Grub, (versus, the listing, say, from fdisk)). Anyway XP will load if I turn off the Gentoo partition, so I did, apparently not mess up my XP MBR.

I think the above link states the question I now have (more) clearly (?), & while I will in the interest of time & sanity (small joke), experiment today... I still could use some advice at the above link... as I am not really that confident of happy resolution... (but still hopefull :))

Thanks much again for you time & energies.

Regards,
Henry
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PostPosted: Sun Jun 09, 2013 7:46 pm    Post subject: Reply with quote

NeddySeagoon wrote:
Allowing ssh access to the root user is a gaping security hole, so as soon as you can, install sudo and configure sshd to reject root logins.
It will still go through the motions, but the password will never succeed.


ssh localhost
password: entered
$USER # su
password: entered
root #

no sudo required.
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cat /etc/*-release
Funtoo Linux - baselayout 2.2.0
consider this warning no. 1
https://wiki.gentoo.org/index.php?title=Special:Contributions/666threesixes666&offset=&limit=500&target=666threesixes666
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PostPosted: Tue Jun 11, 2013 8:36 am    Post subject: Reply with quote

666threesixes666,

True. Well caught!

I set my root password to something very long that I don't intend to remember.
Then I use
Code:
 sudo su -
to get root access with roots environment.

I also use sudo for performing odd root only commands in my normal command flow.
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