More 2 Cent Tips
See also: The Answer Gang's
Knowledge Base
and the LG
Search Engine
The Wonderful World of 2.6
Mon, 14 Jul 2003 11:42:39 -0700
David Benfell (
co from trek.parts-unknown.org)
Question by trek (trek from trek.starshine.org)
Of course a number change doesn't really mean all that much more than
that Linus Torvalds might be trying to push 2.6 out the door a little
faster than what happened with 2.4. Also, for what it's worth, Joe
Pranevich has just put out a draft version of the Wonderful World of
Linux 2.6, posting this to the kernel list:
|
...............
Hello,
I've recently put together the first draft of a features document
describing the changes in Linux 2.6. (I did similar documents for
both Linux 2.2 and Linux 2.4.) It's based almost entirely on
BitKeeper changelogs (with clarifying information pulled from the
lists and the web), so there is a chance that I misunderstood
something or that I missed something else entirely. Please give it
a look over and if you see anything that needs a look-over, please let
me know. As it stands now, I feel pretty good about how it
turned out so I'm finally comfortable mailing what I have around.
(There are still a couple areas that need expanding on, I think...)
As of right now, you can find the latest versions of the document
available online.
Text version: http://www.kniggit.net/wwol26.txt
Tersely formatted HTML: http://www.kniggit.net/wwol26.html
Please let me know what you think.
Thanks,
Joe Pranevich
jpranevich<at>kniggit.net
...............
|
Using 2.6 kernels - get the right tools
Sat, 25 Oct 2003 00:50:59 -0600
Heather Stern (
Linux Gazette Technical Editor)
You need a new modutils variety entirely for 2.5x, and 2.6 kernels.
Under Debian the package name to fetch is called
module-init-tools
The upstream source can be gotten from
ftp://ftp.kernel.org/pub/linux/kernel/people/rusty/modules
As LG goes to press the current available is 0.9.15-pre2.
The nice thing is, it doesn't conflict with modutils.
2.6 kernel - use the latest or expect a leak
Wed, 29 Aug 2003 10:50:59 -0600
Heather Stern (
Linux Gazette Technical Editor)
The current version of 2.6 (test 9) fixes some nasty memory leaks in the
VFS layer for filesystem management. If you've been experimenting along in
the 2.5.x/2.6 series, an upgrade is highly recommended.
[LG 92] 2c Tips #5 - PDF conversion
Mon, 7 Jul 2003 14:09:58 +0100 (BST)
Thomas Adam (
The LG Weekend Mechanic)
Question by Walt R (wmreinemer from tns.net)
In issue 92 Mike Martin asked: Has anyone any ideas on converting PDF's to decent text.
Several of the Gang answered with useful programs.
-- Heather
A loyal reader, Walt R, has sent in:
The tool pdftotext works, but
all formatting disappears.
Yes, an unfortunate side-effect. You might have to edit it by hand, to
re-instate formatting...
[LG 92] help wanted #1 - BiDi and SMARTDRAW
Thu, 03 Jul 2003 22:55:54 +0100
Jimmy O'Regan (
the LG Answer Gang)
In issue 92, Daniel Carneiro do Nascimento's question was pubbed in the
Mailbag's "Help Wanted" section.
-- Heather
BiDi in Wine is still being actively worked on, and is nowhere near
complete. You should resend your e-mail to wine-devel@winehq.com to get
to the people who /really/ know Wine.
[LG 92] help wanted #2 - Squid and FTP
Thu, 17 Jul 2003 12:38:02 +0200
Velibor Glisin (
velibor from uns.ns.ac.yu)
Tru IPcop. It is firewall router. EVERY connection from inside is
working and You are stealth to outsiders.
Not closed... stealth!
http://www.ipcop.org
Try. It is the best I ever used. I have had proxy two months before...
now never again
Bye!
[LG 95] help wanted #2 - webdialer
Tue, 7 Oct 2003 11:54:42 -0400
vlad.dvoichenko-markov (
vlad.dvoichenko-markov from verizon.com)
My solution may or may not be OK for you. I have a little P75 laptop that
acts as a NAT for my local area network. It runs OpenBSD with user PPP. I
am unsure whether user PPP is available for Linux. Maybe you can use pppd
and ipchains (or whatever its called now).
User PPP is configured in "auto" mode such that a request makes it dial out
if its not connected. So if my wife requests an html page, PPP dials out,
connects, and she gets her page. She uses Windows and is NATed thru the
P75.
No users are on the P75. I have had two windows boxes, one FreeBSD box, and
the P75 (ntpd) all sharing the same internet connection concurrently.
Format of Binaries in Linux....
Tue, 7 Oct 2003 04:02:32 -0700 (PDT)
sarfraz b (
bsarfraz_2000 from yahoo.com)
Answered By Thomas Adam, Jim O'Regan, Karl-Heinz Herrmann
Hi,
Could you please help me out to know the format of binaries in Linux.
thanks in advance.
regards
Sarfraz
[Thomas]
From last month's "Greetings from Heather Stern":
The same goes for you students out there with a take home light quiz. We
can spot those a handful of kilometers away, give or take a mile. Maybe
you should cc: your professor when you ask us the question, and he can
give us the passing marks in your class. The point is to learn a few
research skills - so for such questions, search google. Search our
KnowedgeBase - it's part of what it's here for. Search TLDP.org and
freshmeat if the problem is really about Linux.
To give you a hint, there's two types: ELF and a.out
[Jim O'Regan]
-
There's a nice discussion in the FreeBSD handbook
- http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/binary-formats.html
[K.-H.]
try also:
http://www.linuxjournal.com/article.php?sid=1059
as a starting point. Came up in google easily enough.
MS Research vs. open source
Mon, 20 Oct 2003 04:31:41 +0100
Jimmy O'Regan (
the LG Answer Gang)
I was looking at Dashboard (http://www.nat.org/dashboard), and noticed
a link to a Microsoft Research project, MyLifeBits
(http://research.microsoft.com/barc/mediapresence/MyLifeBits.aspx). I
had a look around the site, and noticed that a lot of the projects have
open source equivalents - some of them older than MS's version - and
figured I'd make a list. (Before Dashboard there was the Remembrance
Agent for Emacs, which I think outdates MyLifeBits).
* IntelliShrink (http://research.microsoft.com/~simonco/intellishrink.aspx)
Shrinks e-mail to SMS abrv8tns. Free version: email2sms
(http://adamspiers.org/computing/email2sms)
* World-Wide Media eXchange: (http://wwmx.org)
Tools for stamping image files with their location, as well as tools for
converting location information from GPS handsets to GPX. GPSBabel
<http://gpsbabel.sourceforge.net/>; can write GPX files, you can use
exiftags <http://johnst.org/sw/exiftags/>; to write this to an image.
* AutoDJ (http://research.microsoft.com/~jplatt/abstracts/autoDJ.html)
Automatically generates music playlists. Cymbaline
(http://silmarill.org/cymbaline.htm) does this.
* Media Computing (http://research.microsoft.com/mc)
which has several subprojects, including Audio Content Analysis, which
Maaate (http://www.cmis.csiro.au/maaate) does; Face Detection, Tracking
and Recognition, which OpenCV
(http://www.intel.com/research/mrl/research/opencv) does; Digital
Album, which facilitates the annotation of photos, and searching based
on these annotation - Gnome Storage
(http://www.gnome.org/~seth/storage) can do this, among other things;
Video Content Analysis, Representation and Access - VideoQuery
(http://videoquery.sourceforge.net) can do this.
* Mobile IPv6 (http://research.microsoft.com/mobileipv6)
Mobile IPv6 support is available for Linux - MIPL
(http://www.mipl.mediapoli.com)
* Advanced Compiler Technology (http://research.microsoft.com/act)
Optimising C# compilation. Mono (http://www.go-mono.net) follows
Microsoft's research in this area, and generally implements it.
* Natural Language Processing (http://research.microsoft.com/nlp)
There are several projects available for NLP, for example OpenNLP
(http://opennlp.sourceforge.net)
* Camera Calibration (http://research.microsoft.com/~zhang/Calib)
OpenCV does this too.
* Audio fingerprinting (http://research.microsoft.com/~cburges)
Free Tantrum: (http://sourceforge.net/projects/freetantrum)
* Pastry (http://research.microsoft.com/~antr/Pastry)
A peer to peer system - it's open source, and written in Java, so it
should run on Linux.
* IceCube (http://research.microsoft.com/camdis/icecube.htm)
IceCube allows for disconnected use by mobile clients... just like CODA
(http://www.coda.cs.cmu.edu) does.
* .NET Generics (http://research.microsoft.com/projects/clrgen)
Mono is working on this too.
* SML.NET (http://www.cl.cam.ac.uk/Research/TSG/SMLNET)
SML.NET is Open Source
* The Social Computing Group (http://research.microsoft.com/scg) has a
few projects which have open source equivalents --
** Sapphire: is pretty similar to Gnome Storage
** Conversation clusters: is similar to the vfolders in Ximian's Evolution
** Smart Previews: looks almost exactly like the previews in KDE 3.1
** Shared browsing: You can do this in Mozilla with DerTandemBrowser
(http://dertandembrowser.mozdev.org)
ssh -L 1234:localhost:22 remotehost -s sftp
Wed, 8 Oct 2003 14:36:40 -0400
Ledford, Shaun K [IT] (
shaun.k.ledford from citigroup.com)
Answered By Karl-Heinz Herrmann
The above command is supposed to tunnel all request on port 1234
to secure port 22 and allow a SFTP.
So.. on localhost I should be able to do:
"ftp localhost 1234" and connect via ssh to remotehost ftp remote files.
The problem is, it doesnt work. Is such a thing possible?
Thanks
Shaun.
[K.-H]
well -- I've no idea of sftp as such. according to the manpage this feature
is SSH2 only. Are you sure your connection is protocoll level 2? Check with
"-v".
To put localhost in there confused me for a moment, but it seems to be fine.
You might want to out a real hostname to make it less confusing. Assuming
your ssh is to the ftp-target "remotehost" would do fine.
I get the error:
khh > ssh -L 1234:localhost:22 dachbox -s sftp
usage: sftp [-vC1] [-b batchfile] [-o option] [-s subsystem|path] [-B
buffer_size]
If I force level 2:
ssh -2 -L 1234:localhost:22 khhlap -s sftp
it just sits there. ftp localhost 1234 gets me a ftp interface which is
unconnected. I don't have an ftpd running so I can't test further.
It would be a lot easier to answer anything if you would have sent the
error message or what exactly does not work.
I'm not familiar with the ssh2 "-s" option. I've never used it. But I've
successfully tunneled (using -L) http, smtp, ssl-imap and news ports through
a firewall -- so basically it should work as long as ftp is in passive mode.
[LG #95] answer gang: "a linux solution for the office"
Fri, 17 Oct 2003 01:38:47 -0400
Dave Phillips (
family_of_phillips from yahoo.com)
Answered By Thomas Adam, Ben Okopnik
Reading through the answer to this question I noticed that the hyperlink
for http://ltsp.org was incorrect, included a >, as well as the link for
SIAG office suite was completely wrong. He said http://www.siag.org when
it should have been http://siag.nu.
You guys are doing a great job, but... I think somebody should take the
time to make sure the links are correct at least to avoid sending people
off on snipe hunts.
[Thomas]
OK, that "he" to which Dave refers was actually me. However, as this
goes to press, I cannot help but feel malace towards the tone of this
e-mail. As Ben rightly goes on to say, don't complain or expect anything
to be resolved unless you yourself can do something about it. This is a
volenteer effort afterall.
OK, I admit that I did guess the URL for siag office, but I'm sure that
you, the gentle reader, know how to use google.com/linux? I certainly
hope so...
[Ben]
Cool idea - thanks for voluntering! We'd love to have a proofreader. I
have to warn you, though, that the quantity of mail, submissions, etc.
that we get can be fairly overwhelming, so I hope you're offering a
significant chunk of your time.
HINT: we're all volunteers here. Complaining about someone not taking
the time - when that is the specific resource we contribute (especially
since a number of us are consultants and normally get paid for that very
resource) - is ungracious at the very least.
Helpful suggestions are always welcome. Complaints that aren't coupled
with an offer to help, well, our /dev/null stays hungry no matter how
many pretzels we feed it...
[Thomas]
I almost got my hand bitten off the other day when I tried to feed it
all the MIME-encoded e-mails we get. It seems that /dev/null hates them
even more than we do
I'd watch your fingers in the future, Ben.
That /dev/null device doesn't take any passengers....
LD_DEBUG coolness
Wed, 15 Oct 2003 15:50:50 -0600
Jason Creighton (
androflux from softhome.net)
Hi,
I was reading comp.unix.programmer and came across a comment about setting
the LD_DEBUG environmental varible to 'help' and running a dynamic
executable. Okay, let's try it:
~$ export LD_DEBUG=help
~$ ls
Valid options for the LD_DEBUG environment variable are:
libs display library search paths
reloc display relocation processing
files display progress for input file
symbols display symbol table processing
bindings display information about symbol binding
versions display version dependencies
all all previous options combined
statistics display relocation statistics
help display this help message and exit
To direct the debugging output into a file instead of standard output
a filename can be specified using the LD_DEBUG_OUTPUT environment variable.
See attached ls_output.txt
Fun thing to play with. And who knows, I might actually have a use for
it someday.
[Ben]
*Nice!*
Thanks, Jason - that's a really fine tidbit. It now reposes comfortably
in my toolbox in the little niche by "strace" and keeps it from rolling
around and rattling. I've spent the past week teaching people how to use
the "grep" drill, the "awk" chopsaw, and the "sed" jackhammer, and can
appreciate the finesse of a precision instrument all the more for that
reason...
ximian email backups
Thu, 9 Oct 2003 04:10:44 -0700 (PDT)
- E J - (
vts_ej from yahoo.com)
Answered By Thomas Adam, Jim Dennis, Raj Shekhar
Could someone let me know what files I need to pull
from my current system (where I get my email) to a new
system? I would like to backup all the data and
restore it to a new system and get the email over
there; yet, have all my email folders/emails restored
to the new system.?
Thanks in Advance
EJ
[Raj Shekhar]
If you are using evolution , then in your home directory you will find a
folder called evolution which will have all the mails + contacts + other
settings. If you want to just find your emails, you will find them in
~/evolution/local/Inbox .
A piece of advice, if you back up your mail to a CD and then restore it,
you will have the files which are read-only. I would suggest that you
tar and gunzip your evolution folder before burning it to the CD , that
way your file-permissions will be preserved.
[Thomas]
Actually, that is inaccurate -- one can preserve permissions on CD quite
easily, if they're copied with "cp -p". Also, why put them on CD at all?
You could easily move them to another partition, which would preserve file
permissions as well.
[JimD]
More obviously you can simply create an archive (tar, cpio, dump, pax)
which will preserve the ownership and permissions. That's what Unix
archives do, archive data with meta-data.
Then burn the .tar (or whatever) file into your CDR. Basically you'll
create an ISO containing just one or a few archive files.
(newbie) alsa module ?
Wed, 9 Apr 2003 11:37:33 -0700
Rick Moen (
the LG Answer Gang)
Question by JK Malakar (cave_man from hotpop.com)
here is a confusing problem. I like to insert the alsa module in my woody.
but the alsa-driver source has been located at
*/usr/src/modules/alsa-driver* & the kernel source at
*/usr/src/kernel-source-2.4.18*
make xconfig doesn't show the alsa option. do I need to move the alsa-driver
at a particular directory (?) under the kernel-source to get the alsa option
during make xconfig ??
-
All of this is covered at
- http://www.sonic.net/~rknop/linux/debian_alsa.html
Linux CD trial
Sun, 20 Jul 2003 16:31:32 +0100
Neil Youngman (
n.youngman from ntlworld.com)
Question by Amgam3 (amgam3 from arabia.com)
Hi,
I am interested in Linux and open source in general.I am new to linux, I
read more about it but till now
havn`t tried it. I downloaded small distributions like ' small linux '
but didn`t work. Having only
dial up connection to the Internet it is difficult to download those big
distros over analog phone,
so what I ask is can you send a free CD of a distro of linux to get my
feet wet or point me out
to some sources where to find this.
-
I suggest buying a knoppix CD from
- http://www.linuxemporium.co.uk/index.php?PAGE=4
HTH
Neil Youngman
For those in the US, Cheap Bytes seems to carry it also. And a few more
distros, too, in case a particular one strikes your fancy.
-- Heather
Sendmail 8.12.9 - recreating db files
Sat, 12 Jul 2003 14:26:36 -0500 (COT)
John Karns (
the LG Answer Gang)
Question by francis matsika (tsikaz from yahoo.com)
just finished installing Sendmail, but now
if i run make all in /etc/mail after running
/usr/bin/newaliases, i am getting the following error:
make: No rule to make target 'domaintable.db', needed
by 'all' . Stop
Info
rehat 7.2
Rather than DL'ing the pkg in parts via ftp, I think it would be much more
striaght forward to DL the pkg as a tar or rpm and install from that.
plz help --- Rh9 connecting to ISA server
Thu, 10 Jul 2003 10:41:41 +0100 (BST)
Mike Martin (
the LG Answer Gang)
Hello
I recently installed RH 9 and i have a LAN
running on ISA server, tried to connect it but
could't.
somebody told me configure samba
so i did and now i could also see the computers on
my
network
and even the PING to the server is OK
when i try to browse the network it gives me:
"HTTP 607 proxy Authentication required,
The ISA server requires authorization to fullfill
the request. Access to web proxy service denied (12209)"
it will be very helpful if
anyone can plz suggest me a way out of this problem
Excuse me being a Newbie
Weather i have to configure the ISA (a bit dificult
to access for me) or is there any other way
plz lemme know in either cases
Thanks
FAHAD
-
see this
- http://ibiblio.org/gferg/ldp/Web-Browsing-Behind-ISA-Server-HOWTO.html
Burning ISO's under windows
Sat, 19 Jul 2003 19:58:39 +0000
Jim Dennis (
the LG Answer Guy)
Question by Graham Banks (gjcbanks1 from netscape.net)
Having read the previous answers to this question I would like to
recommend a software program taht I recieved with my Sony Recorder, '
B's Recorder Gold5 ' http://www.bhacorp.com . I found this program to
be very easy, I just loaded the program, cancelled the wizard. Next I
found the ISO file and dragged into the bottom layer, then from the file
menu I selected record and that was it a perfict disk.
Having read mail to this address since before it was a list I would like
to recommend that software recommendations to MS Windows and Mac OS
(non-portable to other forms of UNIX) products be sent just to the
querent and other interested parties.
This is linux-questions-only; the LINUX Gazette "Answer Gang."
Naturally, we'd like to encourage a "Linux-answers-mostly" policy.
A quick search of http://www.freshmeat.net on "ISO CD burn":
http://freshmeat.net/search/?q=iso+cd+burn§ion=projects
... gives me a list of about 25 ISO CDR programs --- I'm sure there
are more than that it's a popular programming and scripting exercise.
Almost all of them are simply GUI, command line or curses (text dialog)
driven front ends to Joerg Schilling's cdrecord and mkisofs
Some also support cdrdao, mkybrid, or related command line tools.
As for DVD-R/RW and DVD+R/RW drives, the support for them seems to be
a bit sketchy. I think they're getting closer but I still haven't
gotten my Ikebana DVD+R/RW drive working yet (except as a CD-R/RW).
(I haven't tried it recently either).
See also the "Best of ISO Burning Under Windows" in our KnowledgeBase.
-- Heather
mail files.
Thu, 3 Jul 2003 11:15:37 +0200
Jimmy O'Regan (
the LG Answer Gang)
Question by Hans Borg (Hans.Borg from physics.umu.se)
Sorry if this is not a "pure" linux item, but I take the chance.
Am trying to convert (import) Eudora (version 3.0.5) .mbx files to the KDE
Kmail. For this I have used the Eudora2Unix.py script. That seems to
work. It reports eg. 529 messages found for a given "folder".
The problem: When having moved the converted .mbx to the appropriate
Kmail folder, I only see the first mail. I can guess that it depends on
the fact that Kmail keeps each mail in a separate file, while my Eudora
stacks them in a single file referred to as folder (thus not a real
folder in normal terminology). It should not be too hard to split the
messages into separate files, but then comes the file naming convention
in Kmail. What I have seen, it looks like a fancy (many digits) running
number.
So, have I missed something with Kmail (option to set) or are there any
s/w available to fix eg. messages -> separate-files.
Hoping for some hints.
Have you tried kmailcvt?
Thanks for your answer.
I have found out the problem. KMail have two folder modes,
maildir and mbox. I happened to move the Eudora mbox folder
into a KMail maildir folder.
What to choose? Mac or PC?
Thu, 20 Feb 2003 12:44:31 -0600
Hubert Chan on debian-laptops (
hubert from uhoreg.ca)
Question by Nate Bargmann (n0nb from networksplus.net)
Just use a repeat_type of raw, so that XFree86 sees exactly the same
thing as it would see if there was no GPM. BTW, I use a mouse type of
autops2, and GPM can recognize the middle button.
Hey, thanks, Hubert. That did the trick. Sometimes I wish tips like
this were a bit more clearly documented, but I digress...
ok, you said winmodems don't work right? - Quick and Dirty Kernel Compile
Tue, 8 Jul 2003 11:01:12 +0100 (BST)
Mike Martin (
the LG Answer Gang)
Question by fire wing (deathmune from hotmail.com)
www.linmodem.org.
i downloaded the driver (most lucent winmodems that aren't AMR
work, )
On the page you can load a binary driver, which means you dont have
to recompile (check the versions tho)
now, i need help working with this beast. i'm using redhat 8.0. it
says i
have to recompile the kernel (i think) and since i am a complete
newbie at
working this stuff (the more i go into linux, the more i learn)
could you
give me some cut and dry instructions on how to install this driver
as
either a module or as a full part of the kernel. I have the kernel
sources
from kernel.org's website (i don't know if the headers come with it
though,
so i need help with this too). i'm an ultra newbie at linux, but in
windows
i am an advanced user.
Quick and dirty RH recompile
First dont use kernel.org sources - RH patch to high heaven.
get kernel source rpm from
ftp.redhat.com/pub/redhat/linux/updates/8.0/en/os/i386/
rpm -ivh <package> to install
cp /usr/src/linux-2.4/configs/<your chosen arch config>
/usr/src/linux-2.4/.config
cd /usr/src/linux-2.4
make menuconfig
then make any changes
save
then
make dep&&make clean&&make bzImage&&make modules&&make
modules_install
then when this is all done
cp boot/arch/i386/bzImage /boot/vmlinuz<your name for kernel here>
cp System.map /boot/System.map<same version as above>
rm -rf /boot System.map
ln -s /boot/System.map etc //boot/System.map
mkinitrd /boot/initrd-<version of kernel>.img version number
then edit /boot/grub.conf to add these details as in the current
entries.
Although RH normally add so many modules you may not need to
recompile.
If this does not work you may not have the dev packages you need.
you need at least
gcc
make
bison
glibc-kernheaders
glibc-devel
ld
cpp-devel
libgcc-devel
(this is from memory so you could need a few more - rpm should tell
you)
thank you for the support.
Cool toy of the week: rlcompleter2
Fri, 11 Jul 2003 06:15:41 +0000
Jason Creighton (
the LG Answer Gang)
Answered By Jim Dennis
http://codespeak.net/rlcompleter2
Tab completion for Python. Cool stuff, now all I can think about is how to
implement this in Ruby.
I've been using the standard rlcompleter for years. What does
rlcompleter2 add to the the standard module?
/me browses(*)
Ahhh, I see; it's sort of like Ian MacDonald's bash-completion package.
It adds context sensitive completions and adds support for displaying
the docstrings (.doc__ attributes for any function, module, or class)
and apparently it displays the function signatures (argument list)
as well.
I'll have to play with it.
/me downloads, plays, configures
Now my PYTHONSTARTUP for python2.2 and python2.3 are set to
~/.pythonrc.rlcompleter2
Thanks.
The startup for interactive sessions is a little slower. there is a
noticeable hesitation during rlcompleter2 .setup() but it's not bad
enough to worry about.
- /me is a IRCism --- traditional IRC clients have a /me command that
highlights one's statement as an "action" --- a description rather
than an utterence
Sendmail Problem
Wed, 16 Jul 2003 20:05:05 +0000
Jim Dennis (
the LG Answer Guy)
Question by Francis Matsika (frmatsika from yahoo.co.uk)
I getting this error : Connection failed to
192.168.0.1,25 Connection refused if i try to sent
mail straight from the server using pine
192.168.*.* are unroutable on the Internet (as per RFC191
. It may
be that the server to which you are connecting is refusing you due to
some internal (anti-spam and/or anti-relaying) configuration rules.
If i try to from windows workstations, the client are
failing to get a response from the server
I checked sendmail status and it is running
I also restarted sendmail and i can only use pine
twice and the third time it will throw the same error
if i run ps -aux | grep sendmail , there is this
process [ sendmail < defunc and at one time there was
sendmail rejected connections running , which i do not understand
I see you've tried to provide additional information but a careful
perusal reveals that you don't give enough RELEVANT information to
actually answer your question.
Try to formulate a better question after you read the following
LDP (Linux Documentation Project) HOWTOs and Guide chapters:
-
Network Administrator's Guide: E-mail
- http://tldp.org/LDP/nag/node186.html
-
Linux E-mail User's HOWTO
- http://tldp.org/HOWTO/Mail-User-HOWTO
-
Linux Administration Made Easy: Sendmail Configuration
- http://tldp.org/LDP/lame/LAME/linux-admin-made-easy/sendmail-upgrades.html
-
ISP-Connectivity-mini-HOWTO: Electronic Mail on your Linux Box
- http://tldp.org/HOWTO/mini/ISP-Connectivity-3.html
-
Forwarding Mail to a Relay Host
- http://tldp.org/LDP/nag/node247.html
-
Linux Mail-Queue mini-HOWTO: Delivering e-mail
- http://tldp.org/HOWTO/mini/Mail-Queue-4.html
... note: I've tried to arrange these roughly in the best order for you
to read them. Basically the first one should explain the concepts and
terminology a little better, then next one might just help you solve
the problem, and the others may help if you're still fighting with it
beyond that. In other words, I don't expect you to read all of those,
just read enough to solve the problem (or at least to be able to better
explain it).
Help needed - Simputer
Wed, 9 Jul 2003 11:39:20 -0700
Heather Stern (
Linux Gazette Technical Editor)
Question by Mythili Srinivasan (s_mythili from da-iict.org)
Hi!
I'm in need of your help. I'm trying to flash some programs into
Simputer and tried using pfc. The configuration for serial communication
is 115200/9600 baud and I get the following response on pfc's debug window.
Debug Messages are Displayed Here..
At first it wasn't clear how this is Linux-y...
> Using port /dev/ttyS0
> Please wait... Initializing....
> This will take about a minute..
> []
> []
> [This is a PicoPeta Simputer...you are assimilated]
:D
> Simputer booted
> Preparing...
> Sending [init 2]
At this time the progress bar stops and the application hangs forever.
Similarly, when I tried using minicom(9600 8N1),I get response from
simputer till the 'Simputer login' prompt and when I entered the login
name, the getty process in Simputer doesn't respond with authetication
validation or anyother message it is suppose to send. I saw the
Is it expecting a PPP connection? or does it have the wrong parity and
databits setting?
rc.sysinit file which spawned a getty with 9600 baud... As in someother
place where I was looking for the solution mentioned that we got to set
the serial port for 115200 baud, I tried to change in the file even
after providing write permission but couldn't write on to the file. So,
You almost certainly have to be root to write into /etc/inittab, and I
cannot imagine any good reason that a regular user account should have
writable access to it.
rc.stsinit itself might not be the right place to put this.
I killed the old getty process and spawned one with the new baud rate.
Set the ispeed and ospeed to same... But,it doesn't work. One thing
clean about the scenario is that from simputer the messages reach the PC
which the other way it is not. It would be of great help if I can get it
working.
Thanks in Advance.
regards,
Mythili
The most popular program to run on Linux boxes to answer on their serial
port, is called 'mgetty'. It has a man page which is amazingly enough,
usually kind of useful, and the typical /etc/inittab has an example line
about how to activate it, commented out. getty is good, but mgetty has
some special features for dealing with serial lines.
115200 is a common max speed for old style serial ports. 9600 is the
bits frequency if using common voice (300 baud or so) with a fairly
popular old line discipline to get bits on different parts of the
carrier wave. Compression tricks are most of what gives faster modems
their claimed speed.
Hope that helps.
telnet prb in linux7.3
Fri, 11 Jul 2003 09:12:11 +0100 (BST)
Ashwin N (
yodha8 from yahoo.co.uk)
Question by S. Rathana Prasad (prasad from jivainfotech.com)
hi every one,
i have two systems one is windows2000 advanced server and another is
linux7.3
iam unable to access it through telnet as superuser.
Access which one of those two?
Maybe you are trying to login as "root" directly at the telnet login. This is
not allowed. You can login as an user and then change to root by using the "su"
command.
Windows
Thu, 24 Jul 2003 09:06:29 +0100 (BST)
Thomas Adam (
The LG Weekend Mechanic)
Question by Frederick Feyertag (fredf from execpc.com)
Dear Mr. Dennis,
Actually, the days when TAG was a one-man-band have long since diminished.
You have actually reached a whole "gang" of us who try and answer
questions based on what querents write in.
I know very little about Linux. I've ran it a few years ago on a 386.
However at the time there weren't too many applications for it. I want a
reliable CAD station but, I have only Windows programs. Does Linux run
Windows applications reliably?
Umm, I think reliably is the operative word. If it is stability you're
after then I would recommend running that application in its native
environment -- windows. However to answer your question, WINE is what
you're after:
http://winehq.com
That does a pretty good job at running Windows apps. There is also the
option of using VMWare if the computer you're connecting to is remote.
If you look through our back issues and also check the KB out:
http://www.linuxgazette.net/tag/kb.html
I remember there being a thread on CAD software for Linux.
True. In fact we have so many CAD and CASE programs that Freshmeat
has to seperate sections for various types. And then there's
modelling.. I understand that you can get very nice, if imprecise,
3D effects with these apps.
-- Heather
LJWNN Tech Tips
Mon, 27 Jan 2003 15:41:22 -0800
Linux Journal Weekly News Notes (
ljwnn from linuxjournal.com)
Apologies, folks - I had published several large LJWNN Tech Tips in
issue 93, but I must have been in too much of a hurry. A few of them were
damaged there, thanks to a formatting mistake on my part. Sorry! Here
are the repaired Tips, please enjoy them.
We will probably not republish Linux Journal Weekly News Notes tips in
future issues of Linux Gazette.
-- Heather
Wireless but Wary - Print Safely
If your main home network is a wireless network, you don't want to
wake up in the morning and find some joker has printed many pages of
stuff to your networked printer. Put the printer on a wired, private
network segment, and print to it with ssh.
To do this, install this script as lpr on your wirelessly connected
laptop:
See attached lpr-ssh.bash.txt
Capture Those Errors
(Thanks to the GAR project:
http://www.lnx-bbc.org/README.html for the tip.)
If you have a lengthy command-line task, such as building complicated
software, and need to catch an error that whizzes by in the middle,
use script. It will run a shell and log all input and output to a file
called "typescript" that you can then search or submit with a bug
report.
Dave's Not Here
The vacation program lets you send an automatic message when you'll be
away from your e-mail. You can see who received your message with
vacation -l | cut -d ' ' -f 1 - > people_who_got_vacation_message
Cure Num Lock Madness
When you boot Linux, the kernel turns off Num Lock by default. This
isn't a problem if, for you, the numeric keypad is the no-man's-land
between the cursor keys and the mouse. But if you're an accountant, or
setting up a system for an accountant, you probably don't want to turn
it on every single time.
Here's the easy way, if you're using KDE. Go to K --> Preferences -->
Peripherals --> Keyboard and select the Advanced tab. Select the radio
button of your choice under NumLock on KDE startup and click OK.
If you only run KDE and want Num Lock on when you start a KDE session,
you're done. Otherwise, read on.
To set Num Lock on in a virtual console, use:
setleds +num
If you choose to put this in a .bashrc file to set Num Lock when you
log in, make it:
setleds +num &> /dev/null
...to suppress the error message you'll get if you try it in an xterm or
over an SSH connection.
Finally, here's the way to hit this problem with a big hammer--make
the numeric keypad always work as a numeric keypad in X, no matter
what Num Lock says. This will make them never work as cursor keys, but
you're fine with that because you have cursor keys, right? Create a
file called .Xmodmap in your home directory, and insert these lines:
(from a Usenet post by Yvan Loranger:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=3BFD087F.2000300%40iquebec.com&rnum=3+)
See attached numpad.Xmodmap.txt
The last line takes the now-useless Num Lock key and makes it an extra
Escape key. If your favorite accounting software uses one of the F
keys frequently, you might prefer that.
The number to the left of the equals sign is an X "keycode", the key
on the keyboard you pressed, and the number or name to the right is an
X "keysym", the character or function X thinks it is. You don't have
to look these up in some X manual. To find out the keycode and keysym
for any key, run xev in an xterm, move the mouse to the small white
xev window and watch the keycodes and keysyms scroll by in the xterm.
SSH a little too forward, use more keys
If you'd like to do SSH port forwarding with a passphrase, but require
a passphrase to run commands, make a separate key for port forwarding
only.
Dramatis personae
dmarti: example user name
bilbo: your desktop system
frodo: host running sshd
linuxjournal.com: some web site
Port forwarding also is called tunneling, so I'll call the key
"tunnel". cd to your .ssh directory and create the key:
dmarti@bilbo:~/.ssh$ ssh-keygen -t dsa -f tunnel
Generating public/private dsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in tunnel.
Your public key has been saved in tunnel.pub.
The key fingerprint is:
77:b4:02:d9:32:c2:cc:18:58:c3:23:0a:13:46:a7:fa dmarti@capsicum
Now edit tunnel.pub and add the following options to the beginning of
the line:
command="/bin/false",no-X11-forwarding,no-agent-forwarding,no-pty
That means this key is no longer any good for anything but port
forwarding, because the only command it will run is /bin/false, and it
won't forward X or agent commands.
sshd understands the options only when reading the key from
authorized_keys, but if you put the options into the original .pub
file, they'll stay with the key wherever it goes.
Now copy tunnel.pub to the end of your .ssh/authorized_keys at all the
hosts to which you want to tunnel, and try it:
dmarti@bilbo:~$ ssh -i ~/.ssh/tunnel frodo
Connection to zork.net closed.
No errors, nothing runs; that's what you want. If you get errors, you
may have mangled the authorized_keys file on the server end; if you
get a shell you need to check and fix the options.
Another possibility is that if you're running with ssh-agent and have
the SSH_AUTH_SOCK environment variable set, you could be using a key
provided by ssh-agent instead of the one on the command line. Put env
-u in front of the command line to be sure not to use the agent.
Tunnel time! Let's use the long-suffering linuxjournal.com web server
as a guinea pig and make a tunnel:
dmarti@bilbo:~$ ssh -i ~/.ssh/tunnel -N -L 8000:linuxjournal.com:80 frodo
To review that command line:
- -i ~/.ssh/tunnel to use our tunnel-only ssh key
- -N to not run a command (this is necessary, otherwise SSH will run
only /bin/false and exit)
- -L 8000:linuxjournal.com:80 to forward local port 8000 to port 80
on linuxjournal.com.
- And finally, the hostname to which we're making the connection--it
doesn't have to be the same as the host to which we're tunneling.
This page edited and maintained by the Editors of Linux Gazette
HTML script maintained by Heather Stern of Starshine Technical Services, http://www.starshine.org/
Published in Issue 96 of Linux Gazette, November 2003
The Answer Gang
Linux Gazette 96: The Answer Gang (TWDT)The Answer Gang 96:
Contents:
- ¶: Greetings From Heather Stern
mandrake linux v9.1 fresh install crashing on first bootup,
- rm : command not found
- Linux "read" issue
- Kernel 2.6.0-test2 and qm_modules error
Greetings from Heather Stern
Greetings, everyone, and welcome once more to the world of The Answer
Gang.
I suppose you would think it obvious what the Peeve Of The Month is.
I'm actaully deeply saddened that this move became necessary, and in fact I
resisted the need at every turn. I resisted the CMS idea too - I think
it's a solution to a problem we don't actually have, and "yet another
slashdot" is not a unique magazine on the scene. But I had hopes that
a talented webmaster could bring a template engine out of its doldrums
and make something amazing and new in a basically already filled niche
of the web. In fact, they still might. But if it can't retain a
regular release schedule, it wouldn't be a Gazette:
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Gazette \Ga*zette"\, n. [F. gazette, It. gazzetta, perh. from
gazetta a Venetian coin (see {Gazet}), said to have been the
price of the first newspaper published at Venice; or perh.
dim. of gazza magpie, a name perh. applied to the first
newspaper; cf. OHG. agalstra magpie, G. elster.]
A newspaper; a printed sheet published periodically; esp.,
the official journal published by the British government, and
containing legal and state notices.
With a basis in official matters (okay, who's perfect) but most
especially in a periodic nature, the only way for the Gazette
to retain its true nature is to remain... a periodical.
But enough of that. 'Tis the time of All Hallow's Eve, and everyone
is dressing up. Me, I'm dressing up my computer. There are some
people doing some really crazy and fun things with new computers. The
silliest that I've seen so far I have to say is the glowing sphere.
That guy's great. His set top box makes it look like that thing is now
a TARDIS or that the aliens who control "The Outer Limits" really have
left their control module visible in your living room. There a bunch of
toasters out there - really! I'm not kidding! Go visit
Mini-ITX.com if you don't
believe me. Cubes even. But the glowing sphere is a winner.
At a basically 7" square motherboard (170 mm, but who's counting) and
about an inch, inch and a half clearance above it, you have anything
from a 500 Mhz to 1 Ghz Cyrix or Eden chipset and most of the useful
peripherals already on board. If you're willing to call it 2.5"
clearance, get a riser card to let you put a PC card in sideways.
I don't know how it is out there with the rest of you but I can run
down to my local computer store here in the Silicon Valley and have my
pick of cases that have clear sections, glowing parts, mounting brackets
for ultraviolet lighting, and ... well I wasn't ready for this at the
time, so make sure you're sitting ... water cooled motherboards. With
somewhat yellow water that glows under blacklight.
Spoooooky. But not half as spooky as the idea that killing a part
of the cooling system isn't just a dead fan and maybe one of the hard
disks will run a risk of much early MTBF - mean time between failures,
the silicon lifeform's equivalent to risk of stroke and heart attack.
Water splattered all over the inside of a 2.3 or 3 Ghz gaming monster
sounds even spookier.
Okay. So maybe I just should stick with a normal case with sort of
bubbly effects on the front. One popular model of this is called the
"alien glow". Sounds like a GIMP filter. If I feel really inventive
maybe I can paint a mural on the side of one of the cases whose sides
pop off easily so techies can get at the parts.
And then, there's making my desktop a little more fun! In this I
have an unfair advantgae. The window manager I happen to favor is
Enlightenment (16 of course. Will 17 never release? Probably.) and
there is an uncountable community of goth kids out there who
really enjoy the spooky backgrounds, razor thin lines, and
dark colors that movie magic reminds us is supposed to be spooky.
Combine that with a decent pile of wallpapers from the K desktop - named
things like "Whirling Spirit" - and all I need is a pumpkin. TuxEyes
can be customized, I think. So someone ought to give it a pumpkin and
flickering littel triangle eyes! Or I can set the root window to
pick up photos of storms and change them every once in a while. Of
course I have a great big hard disk, so loading it up with apropos
music for the spooky little visitors seems perfect too.
Sound, light, Thunder, am I missing anything? Of course. I'll have
to consider getting a remote mouse, or setting my computer up for LIRC -
infrared remote control - so I can toggle the spooky effects without
touching them. Maybe I should set my /etc/hosts file to recognize 127.0.0.1
as localghost. while I'm in here.
Well kids, it's time to wait at the door with the chocolates. For
any of you who haven't run off to the parties, I suggest that a
dessicated pumpkin will not make a good case. Try a big Millenium
Falcon or Enterprise model instead. And... pleasant dreeeeeaams ...
mwa hahahahah ha ha!
mandrake linux v9.1 fresh install crashing on first bootup,
From Michael
Answered By: Thomas Adam, Mike "Sluggo" Orr, Ben Okopnik
hi, i'm fairly new to linux other than i had red hat successfully
installed and working on another computer before. now i got a new
computer and i decided to try mandrake this time because i heard it's
more user friendly which would work well for trying to convert my
finacee from windows.
anyways, i installed mandrake on the second of 3 hard drives in a
dual-boot system.
anyways i ran into a couple big problems. first i installed LILO
graphical boot loader on my seagate 4GB, leaving my main 20GB drive
completely alone but still having the option to boot to windows in lilo,
thankfully because after install i found that if i boot to my 20 GB
drive to get windows my screen types 9A repeatedly for about 6 lines or
so and then goes to a black screen with the message "press a key to
reboot" as i said, thankfully i still can access windows via lilo booted
on my 4GB seagate and i have a rescue mbr and boot record stored on my
6GB.
[Thomas]
Sounds like whatever bootloader is in your MBR (I can't tell from your
description if it is LILO or not) is broken.
now when i try to load linux (my biggest problem really) it does the
initial bios check (ok) and says loading kernel but then my monitor goes
into standby mode as if i shut the computer off.
[Thomas]
Did you read the backpages. I remember that I answered a question on this
very subject. Here is the URL:
http://linuxgazette.net/issue77/tag/2.html
ok, i let it run for a
while while it reads the hard drive, eventually i let it sit for 30
minutes or so with no change and i end up rebooting and here i am. i did
try to turn the monitor back on manually and it just does it's self test
and says check cable connection. i still haven't been able to get linux
to load successfully even in failsafe and no framebuffer modes. i did
have this same install on my second partition of my 20GB but removed it
after hearing that you can't have windows and linux on the same drive
and expect linux to work,
[Thomas]
That is nonsense. You can indeed have Linux and Windows on the same drive,
either by partitioning the free space on that drive for Linux, or by using
the "win4lin" idea, whereby flat files are stored on your windows
partition.
i hoped giving it it's own drive would fix the
problem especially since that was how i had red hat installed and
working on another computer. i don't know why it's not working on this
comp. if anyone out there happens to have a solution for this and !
maybe a reason why the install hashed my mbr on my 20GB i would =
appreciate it.
[Thomas]
Sounds like your monitor's modelines are off. I'd be interested to know
whether or not it is FrameBuffer that causes the monitor to bork. Try this
at the LILO prompt:
linux video="vga16:off"
sorry to sound like an idiot but so you know i'm self taught as far as
computers go and i learned over the years how to do just about anything in
windows, buid a computer, and install and run linux with some intelligence, i
know it doesn't sound like much to the more educated types out there but
[Sluggo]
Not an idiot.
[Ben]
Clearly not, since he's managed to do all of that. To me, "idiot" ==
"uneducable", no matter how "intelligent" someone may be in the common
meaning. Not knowing something does not make you an idiot; being
unwilling to learn when you need to would.
[Sluggo]
There's no way to distinguish EDO and "regular" 72-pin
memory unless says on the chip (good manufacturers) or you've memorized
their numberic codes (which nobody except those who work in the memory
industry do). Most people who put memory in 72-pin computers just sort
their spare memory chips by what "looks similar" and then experiment to
see which ones work together. Of course it depends on the motherboard
too. Most motherboards insist 72-pin memory (SIMM) be installed in
pairs of the same size (megabytes). But my mom's computer works happily
with three 8 MB SIMMs and one slot empty.
DIMMs (168-pin memory) are designed with notches along the bottom to
distinguish their type. You don't have to know the types; you just have
to know that if it's the wrong type, the notches won't fit the
protrusions in the slot and it won't go in.
[Ben]
*AHEM!* Yes it will, Mike. You just haven't repaired enough computers to
know better.
I've seen two floppies "go into" a 5.25" floppy drive
before... and DIMMs would be much simpler: you could _easily use a
hammer to drive them into position. I've seen people jam the 30-pin
SIMMS in backwards, completely uncaring that only one corner of it
actually touched the connector instead of the entire strip being solidly
plugged in. It was in there, by gosh, and *that's* what counted.
[Sluggo]
The manufacturers must have
realized the problem of identical-looking incompatible memory types and
gone to this system to cut down support calls. Fortunately, there's a
company where I live (CompuCare in Seattle) that sells memory with a
lifetime warranty, and they've been good about exchanging it if anything
goes bad.
It's easy to tell whether DIMM memory is the right type,
because if it's not the notches on the bottom won't line up with the slot
and it won't go in.
You think we're not self taught? Some of us have had formal education
in Computer Science and/or as hardware technicians, but I just learned
by trial and error over the years same as you. I worked in workstation
support and at a small ISP for a few years, and that gave me an
opportunity to learn from more knowledgeable ppl whenever it related to
a task at hand. I still remember what a big ordeal it was when I
installed my first CD-ROM (pre-IDE) at home, but now it's a snap.
haven't had the advantages of having a computer my entire life either.
[Sluggo]
I used my first computer in junior high school. It was an Apple II.
how to switch my swap file from hdb2 to hdc* i would
appreciate it.
[Sluggo]
- Create the partition (e.g., /dev/hdc1) and set the type to "Linux swap". Use one of the *fdisk programs (my favorite is cfdisk) or your distribution's GUI installer.
- Run "mkswap /dev/hdc1" to format it.
- Run "swapon /dev/hdc1" to activate it, and "swapoff" the old partition to deactivate it.
- Add a line in /etc/fstab for the new swap partition; comment out the line for the old partition. Linux runs "swapon -a" at boot to activate all swap partitions listed in /etc/fstab.
- (Optional) Change the type of your old partition to Linux, and reformat it with your favorite filesystem (ext3, ext2, reiserfs, etc).
rm : command not found
From requain
Answered By: Ben Okopnik, Thomas Adam
bonjour
depuis un crash de mon serveur X
j'ai sans cesse lors du reboot des messages
rm : command not found
le serveur X ne se lance plus qu 'en faisant en mode console
init 3
/etc/init.d xfs start
init 5
startx
bien sur je pense qu'il me faudrait d'abord recouvrer l'usage de cette
commande rm , qui ne fonctionne plus , en root comme en user
[Thomas]
I'll try and give this my best shot at translation...
Hello,
"My X server crashed, and when I rebooted it, I got the following error:
rm: command not found
The X server doesn't do anything even though I type:
init 3
/etc/init.d/xfs start
init 5
startx
of course, I cannot recover from the error messagem even as the root
user."
[Ben]
This is a much bigger problem than just an "X server crash", although
I'm not sure in what way you're using the term "X server". However, one
thing is apparent: your "rm" command is gone - and since it is part of
"/bin", the directory that contains all your basic system commands, this
is a sign of serious trouble.
[Thomas]
I would summise X crased because it couldn't remove either the temp
files stored in /tmp, or that the various lock files couldn't be removed
from /var/run
[Ben]
In order to delete "rm", someone would have to have root access to your
system. If someone got it and deleted "rm" (which, by the way, is the
command that is used for deleting files), there's nothing to say that
they didn't delete the entire "/bin" directory - or anything else they
wanted to.
[Thomas]
If that were the case, Ben then the system would fail to boot at all,
since "/bin/dmesg" and "/bin/login" woudn't run, hence a huge failure.
[Ben]
This scenario gets just as bad as you want to imagine it, but
in all cases, you need to reinstall the system, change all the
passwords (particularly root), and make sure the system is properly
secured.
There are other, somewhat milder possibilities - like someone with root
access (maybe even you!) accidentally deleting "/bin/rm", or messing up
the PATH variable used in the startup files in "/etc/init.d" (this is a
best-case and very doubtful possibility.) If you're unfamiliar with the
files in "/bin", you need to look at a working system and compare yours
against it; in any case, "rm" should be in there.
Unless you can definitely establish that the problem was caused by
your own mistake (or by anyone else who is authorized to have root
access), I suggest reinstalling as I described above. If some cracker
got into your system (a very incompetent one, if so - deleting "rm" is
obvious _and stupid!), there's no way to tell what sort of traps or
back-doors he may have left in place.
[Thomas]
While it is true that it is often hard to see what a malicious cracker
may or maynot have left behind in his/her wake, there are certain things
known as rootkits which you can use to check to see if the security of
your system has been comprimised or not. But as a general rule, a
re-installation of the base files is usually a good idea.
Linux "read" issue
From Sanford, Kurt
Answered By: Jim Dennis
Hi Jim and Dennis,
Actually, "Jim Dennis" is one person, and the original founder of the
Answer Gang....
-- Thomas Adam
Regarding the problem with:
echo 1 2 3 | read a b c
echo $a $b $c
on Linux ksh (see http://linuxgazette.net/issue57/tag/1.html
<http://linuxgazette.net/issue57/tag/1.html>; ), why are Red Hat and
SuSe using such an old version of ksh? That version of ksh must be
quite old because I have been writing UNIX ksh scripts that do "echo 1 2
3 | read a b c" since at least 1996. Why hasn't the Linux version of
ksh been updated?
[JimD]
I think you misunderstand my point. Some shells read run the implicit
subshell to the right of the pipe (bash, older versions of ksh, etc)
while others run it on the left (newer ksh and zsh).
As far as I know POSIX doesn't specify which behavior is correct.
Therefore the authors of each shell are left to their own judgement for
their own implementations. I personally believe that the new ksh and
zsh semantics are better and provide for cleaner shell scripting code.
The test for any Bourne compatible shell to disambiguate one set of
semantics from the other:
unset foo; echo bar | read foo; echo $foo
If that prints nothing but a blank line, you're running ash, bash, or
and old pdksh or other Bourne shell. If it prints "bar" then you're
running Korn '93(?) or newer, or zsh.
Notice that, around any pipe operator in any shell command there is an
implicit subshell (child process). The pipe is an inter-PROCESS
communications mechanism so there have to be a pair of processes as the
writer and reader to and from the pipe. We're simply asking which side
of the pipe is handled in the sub process and which is handled in the
current process.
Also note that in many cases (when the commands to either side of the
pipe are external) the whole issue is moot. Both will be in child
processes:
cat ./foo | less
... since cat and less are both external commands both are in
subprocesses of the current shell and it doesn't matter what order
the forks were in.
The shell will create one subshell (child process), that will create
the pipe (using the pipe system call) and dup them to stdin and stdout,
then it will create another subshell/process. The (first) child will
then close one of the ends of the pipe (either the read or the write)
and the (second) grandchild will close the other. Then one of them
(with the write end of the pipe still open) will exec*() the cat command
while the other (on the read end of the pipe will exec the less command.
There may be other sequences of system calls that net comparable
results. You could run strace on a number of shells to see.
Kernel 2.6.0-test2 and qm_modules error
From Thomas Adam
Answered By: Thomas Adam, Kapil Hari Paranjape, Jim Dennis
Dear All,
I decided to upgrade my kernel from 2.4.20 to 2.6.0-test2. "No probem",
I thought. So off I trotted to www.kernel.org, selected my UK mirror and
downloaded it, and bunzip/untarred it in /usr/src.
I had planned to implement an ACPI/swsusp patch so that I could
effectively make use of some of the more advanced features of my laptop
in terms of power management. I applied to ACPI patch fine, but the
swsusp patch didn't work, so I removed it.
I copied my /boot/config-2.4.20 to /usr/src/.config and ran a "make
menuconfig". Yay, no problems. I simply added my ACPI settings,
eye-balled the rest of the options, removed support for things like ADFS
and AFS (Andrew's File System) and did a classic:
fakeroot make-kpkg --revision=rev0.1 kernel_image modules_image
Prior to this I had installed and setup "ccache". For those of you who
haven't got this: "apt-get install ccache". Seriously, I recommend it.
It makes successive compilations much faster; by ccache caching the
results. But I digress...
The make went fine, and I was soon "dpkg -i ../kernel_image-rev0.1*.deb"
I did notice that as this was happening, I got a lot of "** Unresolved
Symbols **", but that was alright, because it was in modules that I was
never really going to load, and had put them there for a "just in case"
scenario.
So I went through the motions of "liloconfig" et al and was soon
rebooting my nice new kernel. I have to say that I am impressed thus far
with 2.6.0-test2. Finally Framebuffer support is getting better with the
maintainer of that section actually removing that huge flashing block
and replacing it with a static "_" cursor
As I watched the screen, nothing out of the ordinary was happening, and
I was soon at a login prompt. I did notice that "acpid" (the acpi
software control) didn't load due to "QM_MODULES function not
implemented". Odd I thought. So I logged in (as 'root'), and did a:
lsmod
hmm, I got the following error message:
QM_MODULES function not implemented
"Ok", I thought, how about this:
depmod -a
hmm, same error message.
I wasn't sure what was causing this error, and it was nothing that I had
seen before. So I did the following:
cd /usr/src/linux-2.6.0-test2 && find . | xargs grep -i qm_modules
...guess what? I got nothing! Grep had let me down
. So now I am
thinking that maybe the error isn't listed in any of the textual based
files but that it is statically built into the ".o" files. So....
find . | xargs strings | grep -i qm_modules
...sigh. Nothing, zilch. Of course this last command is slightly
superfluous because in order for the string "qm_modules" to be there, it
would have to come from one of the ".c" files that created the compiled
object file, but I couldn't see how the command could hurt. Now what
should I do???
.... enter "strace"
One of my friends. At this point I was thinking
that maybe I should see just where the "depmod -a" command was failing.
Why did I choose this command and not "lsmod"? Well, in order for the
kernel to know about it's modules and dependencies, it has to make use
of "/lib/modules/$(uname -r)/modules.dep". So, I typed:
strace -o ~/.strace/depmod_2.6.0-test2 depmod -a
had a quick look in the file and yes, sure as I was I could see it
complaining about "qm_modules". Pah, makes no sense to me, really.
What I did next was to boot my "old" 2.4.20 kernel. "liloconfig" is
sufficiently clever to actually keep your old kernel for you. I did
that, and ran:
strace -o ~/.strace/depmod_2.4.20 depmod -a
had a look and that worked fine. Hmmmm, what could be wrong? I ran a
"diff" on the two files, but my brain just cannot make any head nor tail
of what it all means.
I cannot see what, or more importantly where the "QM_MODULES" function
exists. The fact that grepping the kernel source tree returns no
results, suggests that this is a function that is called from no where
within the kernel but rather externally, perhaps from one of the rarer
"glibc" libs?
I tried a google/linux search, but found nothing conclusive. Perhaps I
have compiled something incorrectly in the kernel? I have tried
compiling it many times now, but still the same result. While I am aware
that 2.6.0-test3 exists, the ACPI patch only works for the test-2
branch.
Three files to help you...
1. depmod_2.4.20
2. depmod_2.6.0-test2
3. diff
They can be found here:
http://www.darksatanic.net/ta
My thanks to Hugo Mills for very kindly hosting them. Cheers, Hugo
(number 3 is the difference between the two files. I neglected to do a
unified diff).
Any ideas, tips, points of error would be appreciated.
[Kapil]
Hello,
On Tue, Aug 12, 2003 at 11:48:28AM +0100, Thomas Adam wrote on the
problems he had with the upgrade from 2.4.20 to 2.6.0-test2.
1. Problem with module loading.
2. Problem with Software Suspend (swsusp).
Has any tagger got 2.6.0-testn working successfully?
I did manage to solve problem (1) --- one needs a newer version of
modutils.
[JimD]
:r!ssh vega.starshine.org uname -r
2.6.0-test3
I've been running 2.5.x and 2.6.x kernels most of the time for most
of the last year on vega (my living room desktop system). One of my
housemates (Tabitha) used that system's console more than I did for
most of the last year (she was made to sit in the "comfy chair"
).
I used it quite alot from the other machine in the living room
(usually booted off of KNOPPIX, with ssh and X11 forwarding making it
mostly just a really smart terminal). (An Xterminal with a local
running copy of OpenOffice.org ... hmmmm).
[Kapil]
Problem (2) eludes me. The swsusp patch from swsusp.sf.net for 2.4.21 is
working fine with 2.4.21. I notice that swsusp in 2.6.0 has run into
stormy weather developer-wise so maybe that's the reason.
My main reason for trying out 2.6.0-textn was the support for the i815
framebuffer---just can't do without the Penguin at boot-time
[Thomas]
I did mention that the original reason I was using 2.6.0-test2 was to do
with the swsusp patch. Because 2.6.0 at the time was VERY new (in terms of
the latest stable release), the swsusp people hadn't yet released one that
would work with that version -- hence I dropped it from my patch'd kernel.
I did, however, apply the ACPI patch so that actions such as "lid_close"
on my laptop would be registered by the kernel.
Having updated "module-init-tools" (as I mentioned in my original thread
to this) it still didn't work -- what I did do to try and fix it was to
NOT use "make-kpkg" to compile the kernel. This then fixed my problem.
The only thing i can think of here (albeit loosely) is that fakeroot
caused some weird permissions and/or the package that was produced was
corrupt somehow.
Copyright © 2003
Copying license http://www.linuxgazette.net/copying.html
Published in Issue 96 of Linux Gazette, November 2003
Published in Issue 96 of Linux Gazette, November 2003
Ben is the Editor-in-Chief for Linux Gazette and a member of The Answer Gang.
Memory is the second thing to go, what's the first?
Mobilix