[Techtalk] Debugging/ Troubleshooting book

[Carla Schroder]

On Wednesday 31 July 2002 09:22 pm, hobbit at aloss.ukuu.org.uk wrote:
<Ker-snip>
>
> Indeed. For learning how Unix works, Jon Lasser's "Think UNIX" is a
> great book. I've mentioned this (repeatedly) before, and I don't
> think I'm the only one to like his approach.

Yessum!
>
> > to find the appropriate patch, service pack, or magic combination of
> > reboots and incantations, because applications are allowed to hose the
> > OS, thereby introducing a million zillion skillion possible interactions.
> > Unlike the Unix world, where such interactions are much more limited,
> > plus you can actually dig under the hood to solve problems.
>
> I'm not sure about this. I think distros deliberately limit the
> possible combinations by shipping only one or two or so possible
> apps out of twenty or so apps which all perform the same function.
> Examples are MTAs (which send mail between machinces), MUAs (which
> you use to read mail), window managers, ftp clients, ftp servers,
> editors and shells... and a billion other things.

What I meant was, apps on Windows are much more intermingled with the OS, 
that is why there are so many zillions of unintended consequences and 
botches. The most famous example is .dll hell. For those unfamiliar with 
Windows shared libraries, differing versions have the same name: foo.dll can 
actually have a hundred different incarnations, and often does. Applications 
install these at will and overwrite the existing ones, which often breaks 
other apps.

Not like the sane Unix world, where different versions of a shared library 
are named differently: foo.so.1.1, foo.so.1.2, etc. In the sane Unix world, 
apps are not allowed to modify system files, as they do in Windows.

Interactions in Linux are complex, as you pointed out, but they are 
predictable and logical. Unix is like good mechanics: electricity sparks 
air-fuel mix, which moves piston, which moves crankshaft, which turns 
driveshaft, which turns drive wheel. Windows is like organic chemistry, a 
real unpredictable witches' brew.

> > Sometimes apps have their own troubleshooting utilities, that check
> > syntax and file permissions and such.
>
> Oooh. I haven't met these. Can you give an example or two?

Amanda and Postfix, to name two off the top of my head. Apache. Probably 
others too.

>
> Now that Gnome 2 is out and I have some free time, I am in the
> process of putting together stuff for a website about bug-hunting.
> Any trouble-shooting routines that are intelligible to the, hmm,
> interested amateur rather than the experienced sysadmin, I would
> love to hear about. It currently has notes on everything from
> debugging tools both virtual (script, rpm -V, strace, lsof..)
> and non-virtual (when a screenshot is worth a thousand words..)
> to how to tell the difference between an X hang/crash and a kernel
> hang/crash. More trouble-shooting routines are very welcome:
> saves me having to think them up!
>
> Telsa

For me, the biggest thing is learning the existing Unix utilities. My gosh, 
there's a utility for every damn thing in the world! It's a treasure hunt. I 
browse Running Linux and Linux In A Nutshell just to find new ones. 

Carla