LinuxSA Mailing list archives

  From: David Newall <davidn@rebel.net.au>
  To  : Tyson LT <ua973599@student.adelaide.edu.au>
  Date: Sun, 23 May 1999 15:18:57 +0930 (CST)

Re: SIOCADDRT: invalid argument (???)

Tyson LT <ua973599@student.adelaide.edu.au> wrote:
>> 1. Having fully attempted to resolve the problem before asking for help
>> on the list.
>
> Crap...had it occured to any of you that I did try??? (Why else would I
> *risk* a post...)

I meant you might try to resolve the problem yourself *in light of the new
information which you gained from your first question*.



>    - man -k SIOCADDRT found nothing.

And now you have another tool to add to your repertoire (namely grep in
the manual pages.)


>    - when I ran ALL of the programs mentioned in Redhat's rather
> (over?) complicated network init-scripts, I couldn't reproduce the error
> message.

Despite it not being the purpose of this list, allow me to present some
quite basic thoughts on debugging:  You can't expect to get the same
results from two different runs of a series of complicated, state changing
programs, unless you reset the system to it's initial state between runs.
To put that a little less ambiguously, the state of the networking stack
is (obviously) changed after running the network initialisation scripts.
If you get an error message when you first run those scripts, you must not
expect to get it when you run them the second time.

Here's the single most basic debugging technique: insert trace statements
into the script.  That's where you take:

  #!/bin/sh
  ifconfig blah blah
  route add blah blah blah

and change it to:

  #!/bin/sh
  echo /etc/network/script1 point 1
  ifconfig blah blah
  echo /etc/network/script1 point 2
  route add blah blah blah
  echo /etc/network/script1 point 3

Then restart your computer and instead of getting:

  SIOCADDRT: invalid argument

you get:

  /etc/network/script1 point 1
  /etc/network/script1 point 2
  /etc/network/script2 point 1
  /etc/network/script1 point 3
  /etc/network/script4 point 1
  /etc/network/script4 point 2
  /etc/network/script4 point 3
  SIOCADDRT: invalid argument

The beauty of doing this is that when you subsequently make "a stab in
the twilight," you give people reason to trust your judgment.  (You also
give them more information, like the name of the program, and its arguments,
and the state of the system up to that point.  These *are* the things
which give people reason to trust your judgment.)


> The man page David Newall pointed me to was a kernel programming page, for
> goodness sake.

Yes, for goodness sake!  That's because it was the right man page.


> I think I might cool off trying to persuade my NT-admin friends to try
> Linux, if this is the case. (I think I might be echoing an old religious
> war about elitism amongstUnix users here...)

We're not elitist, we just expect people to hold their own hands (or pay
money to have someone hold their hands for them.) Some people don't want
to learn anything technical, and for them Win NT might be just the ticket.
Of course, they'll end up paying for it at every step of the way.  When
they want to run email: Kaching! goes the cash register; when they want
to connect exchange email via the Internet: Kaching! again; when they
want to serve up web pages: Kaching! Kaching!  And even after all that
Kaching!ing it still won't work quite right.  But at least they'll have
a GUI to point and click at.  By all means do cool off persuading your
NT-admin friends to try Linux, it won't be us playing the cash register
medley.  Kaching!


> Call that basic research?

Yes, actually.  It's called "RTFM", which stands for "read the f manual."
There's nothing advanced about that.

If you don't want to read the whole manual, then use tools to find the
section you need.  It's easy to perform sophisticated searches in Unix,
for example for a manual page which mentions "SIOCADDRT" but doesn't
mention "X.25" unless it also mentions "IP".  Windows doesn't have tools
nearly as powerful, and even if it did, it's help files aren't have as
complete.


> Please forgive me if I sound a little pissed off, but if you can't stand
> newbies, then...well I don't know.

Well yes, you do sound pissed off, which is a pity because if you were
a little less defensive you might notice that you've been getting some
damned good tuition; and for free.  Try getting an MCSE for free.


> I'm also curious about what "Signal 11" means, but I can't find and
> explanation in the manpages...do I dare ask the masters? I might try
> somewhere else first.

I wouldn't advise asking, at least not until after doing basic research.
For the record, I followed the advice you offered, namely man -k, and found
the answer after just three manual pages.


> I think it's a bit sad that some people can set a rather high standard of
> knowledge on SA's (I presume) only Linux list, which I was previously proud
> of, but then refuse to split the list when people that know less than them
> bug them with "dumb" questions.

The problem with splitting the list is that you'd have all the cluefull
people on one list, and all the clueless people on the other, and then
the clueless nobody with any clue to learn from.  At least this way you
are given clue in exchange for occassionally wearing asbestos undies.
I'd say you're on to a good deal, wouldn't you?

Never forget that you are a member of a community.  If you were an artist
you wouldn't expect your peers to draw your preliminary sketches for you;
and you wouldn't expect them to keep giving you paper, pens or paint.
If they did lend you the odd tin or turps to clean your brushes, you
probably would be grateful, and you certainly wouldn't abuse them when
they grumble that you might just go to Eckersley's to buy your own.
Linux is not so different.

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