Re: [BLUG] scp -p preserving ownership through root user

On Thu, 3 Jul 2008, Steven Black wrote:

> You put root's home directory in /home? Just FYI, that's not a
> safe thing to do. It means if you're trying to recover a system
> and /home isn't available you have no configuration files for
> root, and additionally, any files created by root in the home
> directory will land in /. There's nothing like being in a tough
> spot and trying to recover a system and having none of your
> carefully configured system behave as expected. This is what
> will happen if you have root's home directory in /home.
>
> The way the file-system should be structured is that you can
> perform all recovery operations with *only* the / partition
> mounted.
>
> Back in the day the root user didn't have a home directory. It
> was called "root", in part, because the home directory was in
> the root of the file-system. People decided this was a bad idea
> years and years ago, though.
>
> I highly recommend you spend some time playing around with some
> of the command-line options. It is a bad habit to
> over-complicate your command-lines. You can inadvertently find
> yourself having problems that other people just don't
> understand, as they're side-effects of command-line option
> interaction.
>
> Additionally, when you use a lot of command-line options,
> you're opening yourself up to more bugs and hard to reproduce
> behavior. While a lot of the programs you use are probably
> reliable and well-tested, in many environments the rare/obscure
> combinations command-line arguments are the exact places where
> the rare/obscure bugs lie. Option A may work well and be
> well-tested. Option B may work well and be well-tested. Option
> A+Option B may interact in ways that are non-obvious, flat-out
> buggy, and potentially unreproducible.
>
>> But the relevant point to what I was answering is only
>> that tar does not follow symlinks by default; if you want it
>> to track them down and include them, you have to tell it to.
>> Otherwise, using it for the purpose I did, you gradually
>> accumulate obscure but irritating failures of exactly the kind
>> of things I was trying to preserve.
>
> I had to scratch my head on this one.
>
> Why would you want tar to follow symlinks when copying home
> directories?
>
> Tar normally stores and restores symlinks as symlinks. If
> you're symlinking to things which change locations across
> machines in your network, then it is expected that things fall
> apart.
>
> For instance, at home with my personal user account, I keep all
> my data stored one level deep with a dash of source control,
> and a makefile here or there to establish symlinks. It allows
> me to easily backup the data I want to keep and ignore the crap
> that doesn't interest me. All of the symlinks I use in my home
> directory relate directly to other directories in my home
> directory. (And they should all be relative links, so they can
> be moved safely. This also allows me to have multiple copies of
> that data tree and retain internal consistency.)
>
> This also means that if symlinks were followed, I would get
> massive data duplication, some of the source control would be
> violated, and I'd no longer be able to as easily create backups
> of the stuff that is important to me. As an example of some of
> the massive data duplication: Some things have created both a
> 'Music' and a 'music' folder in my home directory in the past,
> both of these, for me, are symlinks to Media/Music, but Media
> itself is a symlink in to the directory I backup regularly. If
> you follow those symlinks, then all my music would be
> duplicated 3 more times.

Wow! What a haul! I'm going to have to go on chewing on
all that for quite a while yet to absorb it as t deserves; but I
thank you immensely for such a trove of clues. Like many
autodidacts, I'm probably stuffed to the ears with things I think
I know that just ain't so -- alas!

--
Beartooth Implacable, Neo-Redneck Linux Enthusiast
Freedom is my issue : I'm pro-choice, pro-right-to-die,
pro-gun, and pro-term-limits. Without defiance, no liberty.
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Re: [BLUG] recommendations on a good digi cam

I'd be interested in this info as well, particularly if there is one camera that is a little more Ubuntu friendlier than others.  (Though I suspect this won't be much of an issue.)
Thanks,
Matt

Ben Shewmaker wrote:

Hey everybody,

I'm in the market for a new digital camera.  I'm looking to spend between $200 and maybe as high as $300 depending on the camera and the deal.  I'm looking for a decent point and shoot, but I don't need anything really advanced or fancy, just want a good quality camera with a good lens that takes great pictures.  I was wondering if anyone has any recommendations?

Thanks!

Ben Shewmaker

 
 _______________________________________________ BLUG mailing list BLUG@linuxfan.com http://mailman.cs.indiana.edu/mailman/listinfo/blug   

[BLUG] recommendations on a good digi cam

Hey everybody,

I'm in the market for a new digital camera.  I'm looking to spend between $200 and maybe as high as $300 depending on the camera and the deal.  I'm looking for a decent point and shoot, but I don't need anything really advanced or fancy, just want a good quality camera with a good lens that takes great pictures.  I was wondering if anyone has any recommendations?

Thanks!

Ben Shewmaker

Re: [BLUG] scp -p preserving ownership through root user

On Thu, Jul 03, 2008 at 06:37:40AM -0700, Beartooth wrote:
> Well, I left out two things, anyway. I always do the full nine yards of
> scp -- with -r, and both IPs, full paths, the works -- just because
> that's the only I have a better than even chance of getting it right and
> making it do what I mean it to. Also, for the record, I usually did all
> of /home, as root (in order to get things like root's .bash_history); so
> of course I also had to do a chown at the other end.

You put root's home directory in /home? Just FYI, that's not a safe
thing to do. It means if you're trying to recover a system and
/home isn't available you have no configuration files for root, and
additionally, any files created by root in the home directory will land
in /. There's nothing like being in a tough spot and trying to recover
a system and having none of your carefully configured system behave as
expected. This is what will happen if you have root's home directory in
/home.

The way the file-system should be structured is that you can perform all
recovery operations with *only* the / partition mounted.

Back in the day the root user didn't have a home directory. It was
called "root", in part, because the home directory was in the root of
the file-system. People decided this was a bad idea years and years ago,
though.

I highly recommend you spend some time playing around with some of
the command-line options. It is a bad habit to over-complicate your
command-lines. You can inadvertently find yourself having problems
that other people just don't understand, as they're side-effects of
command-line option interaction.

Additionally, when you use a lot of command-line options, you're opening
yourself up to more bugs and hard to reproduce behavior. While a lot
of the programs you use are probably reliable and well-tested, in many
environments the rare/obscure combinations command-line arguments are
the exact places where the rare/obscure bugs lie. Option A may work well
and be well-tested. Option B may work well and be well-tested. Option
A+Option B may interact in ways that are non-obvious, flat-out buggy,
and potentially unreproducible.

> But the relevant point to what I was answering is only that tar does not
> follow symlinks by default; if you want it to track them down and include
> them, you have to tell it to. Otherwise, using it for the purpose I did,
> you gradually accumulate obscure but irritating failures of exactly the
> kind of things I was trying to preserve.

I had to scratch my head on this one.

Why would you want tar to follow symlinks when copying home directories?

Tar normally stores and restores symlinks as symlinks. If you're
symlinking to things which change locations across machines in your
network, then it is expected that things fall apart.

For instance, at home with my personal user account, I keep all my data
stored one level deep with a dash of source control, and a makefile here
or there to establish symlinks. It allows me to easily backup the data
I want to keep and ignore the crap that doesn't interest me. All of the
symlinks I use in my home directory relate directly to other directories
in my home directory. (And they should all be relative links, so they
can be moved safely. This also allows me to have multiple copies of that
data tree and retain internal consistency.)

This also means that if symlinks were followed, I would get massive
data duplication, some of the source control would be violated, and
I'd no longer be able to as easily create backups of the stuff that is
important to me. As an example of some of the massive data duplication:
Some things have created both a 'Music' and a 'music' folder in my
home directory in the past, both of these, for me, are symlinks to
Media/Music, but Media itself is a symlink in to the directory I backup
regularly. If you follow those symlinks, then all my music would be
duplicated 3 more times.

Cheers,
Steven Black

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Re: [BLUG] scp -p preserving ownership through root user

On Wed, 2 Jul 2008, Shing-Shong Shei wrote:

> It doesn't look like you were using tar??? If you use tar, you
> should have only one file and you don't need 'scp -r'; e.g.,
[...]
> Am I missing something?

Well, I left out two things, anyway. I always do the full
nine yards of scp -- with -r, and both IPs, full paths, the works
-- just because that's the only I have a better than even chance
of getting it right and making it do what I mean it to. Also, for
the record, I usually did all of /home, as root (in order to get
things like root's .bash_history); so of course I also had to do
a chown at the other end.

But the relevant point to what I was answering is only
that tar does not follow symlinks by default; if you want it to
track them down and include them, you have to tell it to.
Otherwise, using it for the purpose I did, you gradually
accumulate obscure but irritating failures of exactly the kind of
things I was trying to preserve.

--
Beartooth Staffwright, Not Quite Clueless Power User
Fedora 8 & 9; Alpine 1.10, Pan 0.132; Privoxy 3.0.6;
Dillo 0.8, Epiphany 2, Firefox 2 & 3, Galeon 2, Opera 9
Remember I know little (precious little!) of where up is.

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[BLUG] NEXT BLUG meeting- July 15 at the library

All-

I'm pushing the meeting back by one week this month, to July 15th (a
week after we'd normally have it) and have updated the wiki to reflect
this (yep, I remembered to update the wiki; shocking, I know!).

What: Next BLUG Meeting
Why: Mark Krenz will be demonstrating Asterisk
Where: Monroe County Public Library, meeting room 1A
When: Tuesday, July 15 2008

I'll be very difficult to reach from the 4th (Friday) up until a day or
two before the meeting; if you write and I don't respond, don't be
surprised.

What is Asterisk? Asterisk is an open source phone system for Linux.
It can run (with special hardware) connected to POTS (plain old
telephone service; the outside world), or it can run as a pure VOIP
system using IP phones and "softphones" (with your mic and headset, or
similar). It can be connected to a single line or many lines and then
run to extensions for everybody with voice mail, on-hold music, etc (if
you like).

Asterisk is mature, *very* full-featured, relatively easy to program (as
they say: easy to learn, a challenge to master), and suitable for
anything from talking amongst friends, to an enterprise phone system for
your company (I really mean that).

If you have any interest in telephony, VOIP, or real-time communication
via the internet, I strongly suggest you come along and check out Mark's
talk.

Happy Independence Day!
Cooley

--
Dave Cooley
dcooley@kiva.net

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Re: [BLUG] scp -p preserving ownership through root user

It doesn't look like you were using tar??? If you use tar, you should
have only one file and you don't need 'scp -r'; e.g.,

cd /home
tar cvzf user.tar.gz user
scp user.tar.gz remote_machine:

Later you do

cd /home
scp remote_machine:usr.tar.gz
tar xvzf usr.tar.gz

Am I missing something?

Shing-Shong

>
> Here's one more. Before any fresh install, I used to do tar -xvzf
> on /home/user, then scp -r the tarball to another machine, then scp -r
> back after the install. But all sorts of oddments got messed up; I
> found out eventually that tar -xvzf doesn't follow symlinks.
>
> There's another switch for that, I disremember which. Instead of
> learning it, I got lazy, and just took to using some third machine
> while scp took up the bandwidth -- this on a mere home LAN, of course.
>

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