Linux-Misc Digest #410, Volume #21 Sun, 15 Aug 99 15:13:14 EDT
Contents:
Linux Frequently Asked Questions with Answers (Part 6 of 6) ([EMAIL PROTECTED])
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From: [EMAIL PROTECTED]
Crossposted-To: news.answers,comp.answers
Subject: Linux Frequently Asked Questions with Answers (Part 6 of 6)
Date: 15 Aug 1999 18:24:27 GMT
Archive-Name: linux/faq/part6
URL: http://www.mainmatter.com/
Posting-Frequency: weekly
Last-modified: 08/15/99
Linux is a very good memory tester--much better than MS-DOS based
memory test programs.
Reportedly, some clone x87 math coprocessors can cause problems. Try
compiling a kernel with math emulation ( How do I upgrade/recompile my
kernel? .) You may need to use the "no387" kernel command line flag
on the LILO prompt to force the kernel to use math emulation, or it
may be able to work and still use the '387, with the math emulation
compiled in but mainly unused.
More information about this problem is available on the Web at
http://www.bitwizard.nl/sig11/.
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9.8 shell-init: permission denied when I log in.
Your root directory and all the directories up to your home directory
must be readable and executable by everybody. See the manual page for
chmod or a book on Unix for how to fix the problem.
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9.9 No utmp entry. You must exec ... when I log in.
Your /var/run/utmp is screwed up. You should have
> /var/run/utmp
in your /etc/rc.local or /etc/rc.d/*. See ("I have screwed up my
system and can't log in to fix it.") Note that the utmp may also be
found in /var/adm/ or /etc/ on some older systems.
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9.10 Warning--bdflush not running.
Modern kernels use a better strategy for writing cached disk blocks.
In addition to the kernel changes, this involves replacing the old
update program which used to write everything every 30 seconds with a
more subtle daemon (actually a pair), known as bdflush.
Get bdflush-n.n.tar.gz from the same place as the kernel source code (
How do I upgrade/recompile my kernel? ) and compile and install it.
Bdflush should be started before the usual boot-time file system
checks. It will work fine with older kernels as well, so there's no
need to keep the old update around.
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9.11 Warning: obsolete routing request made.
This is nothing to worry about. The message means that your version
route is a little out of date, compared to the kernel. You can make
the message go away by getting a new version of route from the same
place as the kernel source code. ( How do I upgrade/recompile my
kernel? )
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9.12 EXT2-fs: warning: mounting unchecked file system.
You need to run e2fsck (or fsck -t ext2 if you have the fsck front end
program) with the -a option to get it to clear the `dirty' flag, and
then cleanly unmount the partition during each shutdown.
The easiest way to do this is to get the latest fsck, umount, and
shutdown commands, available in Rik Faith's util-linux package
("Where can I get Linux material by FTP?") You have to make sure that
your /etc/rc*/ scripts use them correctly.
NB: don't try to check a file system that's mounted read/write--this
includes the root partition if you don't see
VFS: mounted root ... read-only
at boot time. You must arrange to mount the root file system read/only
to start with, check it if necessary, and then remount it read/write.
Read the documentation that comes with util-linux to find out how to
do this.
Note that you need to specify the -n option to mount so it won't try
to update /etc/mtab, since the root file system is still read-only,
and this will otherwise cause it to fail.
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9.13 EXT2-fs warning: maximal count reached.
This message is issued by the kernel when it mounts a file system
that's marked as clean, but whose "number of mounts since check"
counter has reached the predefined value. The solution is to get the
latest version of the ext2fs utilities (e2fsprogs-0.5b.tar.gz at the
time of writing) from the usual sites. ("Where can I get Linux
material by FTP?")
The maximal number of mounts value can be examined and changed using
the tune2fs program from this package.
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9.14 EXT2-fs warning: checktime reached.
Kernels from 1.0 onwards support checking a file system based on the
elapsed time since the last check as well as by the number of mounts.
Get the latest version of the ext2fs utilities. "(EXT2-fs warning:
maximal count reached.")
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9.15 df says Cannot read table of mounted file systems.
There is probably something wrong with your /etc/mtab or /etc/fstab
files. If you have a reasonably new version of mount, /etc/mtab should
be emptied or deleted at boot time (in /etc/rc.local or /etc/rc.d/*),
using something like
rm -f /etc/mtab*
Some versions of SLS have an entry for the root partition in /etc/mtab
made in /etc/rc* by using rdev. This is incorrect--the newer versions
of mount do this automatically.
Other versions of SLS have a line in /etc/fstab that looks like:
/dev/sdb1 /root ext2 defaults
This is wrong. /root should read simply /.
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9.16 fdisk says Partition X has different physical/logical ...
If the partition number (X, above) is 1, this is the same problem as
in "fdisk: Partition 1 does not start on cylinder boundary."
If the partition begins or ends on a cylinder numbered greater than
1024, this is because the standard DOS disk geometry information
format in the partition table can't cope with cylinder numbers with
more than 10 bits. You should see "How can I get Linux to work with
my disk?"
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9.17 fdisk: Partition 1 does not start on cylinder boundary.
The version of fdisk that comes with many Linux systems creates
partitions that fail its own validity checking. Unfortunately, if
you've already installed your system, there's not much you can do
about this, apart from copying the data off the partition, deleting
and remaking it, and copying the data back.
You can avoid the problem by getting the latest version of fdisk, from
Rik Faith's util-linux package (available on all the usual FTP sites).
Alternatively, if you are creating a new partition 1 that starts in
the first cylinder, you can do the following to get a partition that
fdisk likes.
* Create partition 1 in the normal way. A `p' listing will produce
the mismatch complaint.
* Type `u' to set sector mode and do `p' again. Copy down the number
from the "End" column.
* Delete partition 1.
* While still in sector mode, re-create partition 1. Set the first
sector to match the number of sectors per track. This is the
sector number in the first line of the `p' output. Set the last
sector to the value you wrote down in the step above.
* Type `u' to reset cylinder mode and continue with other
partitions.
Ignore the message about unallocated sectors--they refer to the
sectors on the first track apart from the Master Boot Record, and they
are not used if you start the first partition in track 2.
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9.18 fdisk says partition n has an odd number of sectors.
The PC disk partitioning scheme works in 512-byte sectors, but Linux
uses 1K blocks. If you have a partition with an odd number of sectors,
the last sector is wasted. Ignore the message.
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9.19 mtools says cannot initialize drive XYZ
This means that mtools is having trouble accessing the drive. This can
be due to several things.
Often this is due to the permissions on floppy drive devices
(/dev/fd0* and /dev/fd1*) being incorrect--the user running mtools
must have the appropriate access. See the manual page for chmod for
details.
Most versions of mtools distributed with Linux systems (not the
standard GNU version) use the contents of a file /etc/mtools to
determine which devices and densities to use, in place of having this
information compiled into the binary. Mistakes in this file often
cause problems. There is often no documentation about this.
For the easiest way to access your MS-DOS files (especially those on a
hard disk partition) see How do I access files on my DOS partition or
floppy? Note--you should never use mtools to access files on an
msdosfs mounted partition or disk!
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9.20 At the start of booting: Memory tight
This means that you have an extra-large kernel, which means that Linux
has to do some special memory-management magic to be able to boot
itself from the BIOS. It isn't related to the amount of physical
memory in your machine. Ignore the message, or compile a kernel
containing only the drivers and features you need. ("How do I
upgrade/recompile my kernel?)"
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9.21 My syslog says `end_request: I/O error, ...'.
This error message, and messages like it, almost always indicate a
hardware error with a hard drive.
This commonly indicates a hard drive defect. The only way to avoid
further data loss is to completely shut own the system. You must also
make sure that whatever data is on the drive is backed up, and restore
it to a non-defective hard drive.
This error message may also indicate a bad connection to the drive,
especially with homebrew systems. If you install an IDE drive, ALWAYS
use new cables. It's probably is a good idea with SCSI drives, too.
In one instance, this error also seemed to coincide with a bad ground
between the system board and the chassis. Be sure that all electrical
connections are clean and tight before placing the blame on the hard
drive itself.
[Peter Moulder, Theodore T'so]
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9.22 You don't exist. Go away.
This is not a viral infection :-). It comes from programs like write,
talk, and wall, if your invoking UID doesn't correspond to a valid
user (probably due to /etc/passwd being corrupted), or if the session
(pseudoterminal, specifically) you're using isn't properly registered
in the utmp file (probably because you invoked it in a funny way).
======================================================================
10. The X Window System.
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10.1 Does Linux support X?
Yes. Linux uses XFree86 (the current version is 3.3.3, which is based
on X11R6). You need to have a video card which is supported by
XFree86. See the Linux XFree86 HOWTO for more details.
Most Linux distributions nowadays come with an X installation.
However, you can install or upgrade your own, from
/pub/Linux/X11/Xfree86-* on metalab.unc.edu and its mirror sites, or
from http://www.xfree86.org.
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10.2 Where can I get an XF86Config for my system?
See the Linux XFree86 HOWTO, recent versions of Installation and
Getting Started, and the instructions for the XF86Setup program.
The contents of the XF86Config file depend on the your exact
combination of video card and monitor. It can either be configured by
hand, or using the XF86Setup utility. Read the instructions that came
with XFree86, in /usr/X11R6/lib/X11/etc. The file you probably need to
look at most is README.Config.
You should not use the sample XF86Config.eg file which is included
with newer versions of XFree86 verbatim, because the wrong video clock
settings can damage your monitor.
Please don't post to comp.os.linux.x asking for an XF86Config, and
please don't answer such requests.
----------------------------------------------------------------------
10.3 What desktop environments run on Linux?
Linux with XFree86 supports the KDE, GNOME, and commercial CDE desktop
environments, among other desktop managers. Each uses a different set
of libraries and provides varying degrees of MS Windows-like look and
feel.
Information on KDE is available from http://www.kde.org/. The KDE
environment uses the Qt graphics libraries, available from
http://www.qt.org. The desktop uses its own window manager, kwm, and
provides a MS Windows-like look and feel.
The GNOME home page is http://www.gnome.org/. The environment uses the
free GTK libraries, available from http://www.gtk.org/, and the
Enlightenment window manager, available from
http://www.enlightenment.org/.
The commercial CDE environment uses the Motif libraries and window
manage, mwm. It is available from various commercial vendors. A free
version of Motif, called LessTiF, is available from
http://www.lesstif.org/.
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10.4 xterm logins show up strangely in who, finger.
The xterm that comes with XFree86 2.1 and earlier doesn't correctly
understand the format that Linux uses for the /var/adm/utmp file,
where the system records who is logged in. It therefore doesn't set
all the information correctly.
The Xterms in XFree86 3.1 and later versions fix this problem.
----------------------------------------------------------------------
10.5 I can't get X to work right.
Read the XFree86 HOWTO--note the question and answer section.
Try reading comp.windows.x.i386unix--specifically read the the FAQ for
that group.
Please don't post X or XFree86 related questions to comp.os.linux.x
unless they are Linux-specific.
======================================================================
11. How to get further assistance.
----------------------------------------------------------------------
11.1 You still haven't answered my question!
Please read all of this answer before posting. I know it's a bit long,
but you may be about to make a fool of yourself in front of 50,000
people and waste hundreds of hours of their time. Don't you think it's
worth spending some of your time to read and follow these
instructions?
If you think an answer is incomplete or inaccurate, please e-mail
Robert Kiesling at [EMAIL PROTECTED]
Read the appropriate Linux Documentation Project books--see "Where
can I get the HOWTO's and other documentation?"
If you're a Unix or Linux newbie, read the FAQ for
comp.unix.questions, and those for any of the other comp.unix.* groups
that may be relevant.
Linux has so much in common with commercial unices, that almost
everything you read there will apply to Linux. The FAQs, like all
FAQs, be found on rtfm.mit.edu in /pub/usenet/news.answers (the
[EMAIL PROTECTED] can send you these files, if you don't have
FTP access). There are mirrors of rtfm's FAQ archives on various
sites--check the Introduction to *.answers posting, posted, or look in
news-answers/introduction in the directory above.
Check the relevant HOWTO for the subject in question, if there is one,
or an appropriate old style sub-FAQ document. Check the FTP sites.
Try experimenting--that's the best way to get to know Unix and Linux.
Read the documentation. Check the manual pages (type "man man" if
you don't know about manual pages. Try "man -k subject"--it often
lists useful and relevant manual pages.
Check the Info documentation (type C-h i, i.e. Control H followed by I
in Emacs). This isn't just for Emacs. For example, the GCC
documentation lives here as well.
There will also often be a README file with a package that gives
installation and/or usage instructions.
Make sure you don't have a corrupted or out-of-date copy of the
program in question. If possible, download it again and re-install
it--you probably made a mistake the first time.
Read comp.os.linux.announce--this often contains very important
information for all Linux users.
General X Window System questions belong in comp.windows.x.i386unix,
not in comp.os.linux.x. But read the group first (including the FAQ),
before you post.
Only if you have done all of these things and are still stuck, should
you post to the appropriate comp.os.linux.* newsgroup. Make sure you
read the next question first. "(What to put in a request for help.)"
----------------------------------------------------------------------
11.2 What to put in a request for help.
Please read the following advice carefully about how to write your
posting or email. Making a complete posting will greatly increase the
chances that an expert or fellow user reading it will have enough
information and motivation to reply.
This advice applies both to postings asking for advice and to personal
email sent to experts and fellow users.
Make sure you give full details of the problem, including:
* What program, exactly, you are having problems with. Include the
version number if known and say where you got it. Many standard
commands tell you their version number if you give them a
--version option.
* Which Linux release you're using (Red Hat, Slackware, Debian, or
whatever) and what version of that release.
* The exact and complete text of any error messages printed.
* Exactly what behavior you expected, and exactly what behavior you
observed. A transcript of an example session is a good way to show
this.
* The contents of any configuration files used by the program in
question and any related programs.
* What version of the kernel and shared libraries you have
installed. The kernel version can be found by typing uname -a, and
the shared library version by typing ls -l /lib/libc.so.4.
* Details of what hardware you're running on, if it seems
appropriate.
You are in little danger of making your posting too long unless you
include large chunks of source code or uuencoded files, so err on the
side of giving too much information.
Use a clear, detailed Subject line. Don't put things like `doesn't
work', `Linux', `help', or `question' in it--we already know that.
Save the space for the name of the program, a fragment of an error
message, or summary of the unusual behavior.
If you report an `unable to handle kernel paging request' message,
follow the instructions in the Linux kernel sources README file for
turning the numbers into something more meaningful. If you don't do
this, no one who reads your post will be able to do it for you. The
mapping from numbers to function names varies from one kernel to
another.
Put a summary paragraph at the top of your posting.
At the bottom of your posting, ask for responses by email and say
you'll post a summary. Back this up by using Followup-To: poster.
Then, actually post the summary in a few days or a week or so. Don't
just concatenate the replies you got--summarize. Putting the word
SUMMARY in your summary's Subject line is also a good idea. Consider
submitting the summary to comp.os.linux.announce.
Make sure your posting doesn't have an inappropriate References:
header line. This marks your article as part of the thread of the
article referred to, which will often cause it to be junked by
readers, along with the rest of a boring thread.
You might like to say in your posting that you've read this FAQ and
the appropriate HOWTO's--this may make people less likely to skip your
posting.
Remember that you should not post email sent to you personally without
the sender's permission.
----------------------------------------------------------------------
11.3 I want to mail someone about my problem.
Try to find the author or developer of whatever program or component
is causing you difficulty. If you have a contact point for your Linux
distribution, you should use it.
Please put everything in your e-mail message that you would put in a
posting asking for help.
Finally, remember that, despite the fact that most of the Linux
community are very helpful and responsive to e-mailed questions,
you're asking for help from unpaid volunteers, so you have no right to
expect an answer.
======================================================================
12. Acknowledgments and administrivia.
----------------------------------------------------------------------
12.1 Feedback is invited.
Please send me your comments on this FAQ.
I accept contributions to the FAQ in any format. All contributions,
comments, and corrections are gratefully received. Please send e-mail
to [EMAIL PROTECTED]
If you wish to refer to a question in the FAQ, it's better for me if
you do so by the question heading, rather than number. The question
numbers are generated automatically, and I don't see them in the
source file I edit.
I prefer comments in English to patch files--context diff is not my
first language.
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12.2 Formats in which this FAQ is available.
This document is available as an ASCII text file, an HTML World Wide
Web page, Postscript, and as a USENET news posting.
All of these formats are generated from SGML source using SGML Tools
and the LinuxDoc DTD.
The Usenet version is posted regularly to news.answers, comp.answers,
comp.os.linux.misc, and comp.os.linux.announce. It is archived at
ftp://rtfm.mit.edu/pub/usenet-by-hierarchy/comp/os/linux/misc/.
If you would like to receive the archived version of the FAQ by
e-mail, send the following in the body of an e-mail message to
[EMAIL PROTECTED]:
send faqs/linux/faq
The text, HTML, SGML, and Postscript versions are available from the
Linux archives at metalab.unc.edu, and from
http://metalab.unc.edu/LDP/, but they may be out of date, owing to
lack of time on the LDP maintainers' parts.
The up-to-date text and HTML versions are available at
http://www.mainmatter.com and directly from the FAQ maintainer,
[EMAIL PROTECTED]
----------------------------------------------------------------------
12.3 Authorship and acknowledgments.
This FAQ is compiled and maintained by Robert Kiesling
[EMAIL PROTECTED], with assistance and comments from Linux
activists all over the world.
Special thanks are due to Matt Welsh, who moderated
comp.os.linux.announce and comp.os.linux.answers, coordinated the
HOWTO's and wrote substantial portions of many of them, Greg Hankins
and Timothy Bynum, the former and current Linux Documentation Project
HOWTO maintainers, Lars Wirzenius and Mikko Rauhala, the former and
current moderators of comp.os.linux.announce, Marc-Michel Corsini, who
wrote the original Linux FAQ, and Ian Jackson, the previous FAQ
maintainer. Thanks also to Roman Maurer for his many updates and
additions, especially with European Web sites, translations, and
general miscellany.
Last but not least, thanks to Linus Torvalds and the other
contributors to Linux for giving us something to talk about!
----------------------------------------------------------------------
12.4 Disclaimer and Copyright.
Note that this document is provided `as is'. The information in it is
not warranted to be correct. Use it at your own risk.
Linux Frequently Asked Questions with Answers is Copyright (c) 1997,
1998 by Robert Kiesling [EMAIL PROTECTED], under the copyright of
the Linux Documentation Project. The full text of the LDP copyright is
available via anonymous FTP from metalab.unc.edu, in the directory
/pub/Linux/docs/LDP, and is included below.
Portions are Copyright (c) 1994, 1995, 1996 by Ian Jackson, the
previous Linux FAQ maintainer.
Linux Frequently Asked Questions with Answers may be reproduced and
distributed in its entirety (including this authorship, copyright, and
permission notice), provided that no charge is made for the document
itself, without the author's consent. This includes "fair use"
excerpts like reviews and advertising, and derivative works like
translations.
Note that this restriction is not intended to prohibit charging for
the service of printing or copying the document.
Exceptions to these rules may be granted. I would be happy to answer
any questions regarding this copyright. E-mail me at
[EMAIL PROTECTED] As the license below says, these restrictions
are here to protect the contributors, not to restrict you as educators
and learners.
LINUX DOCUMENTATION PROJECT COPYING LICENSE
Last modified 6 January 1997
The following copyright license applies to all works by the Linux
Documentation Project.
Please read the license carefully---it is somewhat like the GNU
differ from what you may be used to. If you have any questions, please
email the LDP coordinator, [EMAIL PROTECTED]
The Linux Documentation Project manuals may be reproduced and
distributed in whole or in part, subject to the following conditions:
All Linux Documentation Project manuals are copyrighted by their
respective authors. THEY ARE NOT IN THE PUBLIC DOMAIN.
* The copyright notice above and this permission notice must be
preserved complete on all complete or partial copies.
* Any translation or derivative work of Linux Installation and
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* If you distribute Linux Installation and Getting Started in part,
instructions for obtaining the complete version of this manual
must be included, and a means for obtaining a complete version
provided.
* Small portions may be reproduced as illustrations for reviews or
quotes in other works without this permission notice if proper
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* The GNU General Public License referenced below may be reproduced
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Exceptions to these rules may be granted for academic purposes: Write
to the author and ask. These restrictions are here to protect us as
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code in Linux Installation and Getting Started is placed under the GNU
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PUBLISHING LDP MANUALS
If you're a publishing company interested in distributing any of the
LDP manuals, read on.
By the license given in the previous section, anyone is allowed to
publish and distribute verbatim copies of the Linux Documentation
Project manuals. You don't need our explicit permission for this.
However, if you would like to distribute a translation or derivative
work based on any of the LDP manuals, you must obtain permission from
the author, in writing, before doing so.
All translations and derivative works of LDP manuals must be placed
under the Linux Documentation License given in the previous section.
That is, if you plan to release a translation of one of the manuals,
it must be freely distributable by the above terms.
You may, of course, sell the LDP manuals for profit. We encourage you
to do so. Keep in mind, however, that because the LDP manuals are
freely distributable, anyone may photocopy or distribute printed
copies free of charge, if they wish to do so.
We do not require to be paid royalties for any profit earned from
selling LDP manuals. However, we would like to suggest that if you do
sell LDP manuals for profit, that you either offer the author
royalties, or donate a portion of your earnings to the author, the LDP
as a whole, or to the Linux development community. You may also wish
to send one or more free copies of the LDP manual that you are
distributing to the author. Your show of support for the LDP and the
Linux community will be very appreciated.
We would like to be informed of any plans to publish or distribute LDP
manuals, just so we know how they're becoming available. If you are
publishing or planning to publish any LDP manuals, please send email
to Matt Welsh (email [EMAIL PROTECTED]).
We encourage Linux software distributors to distribute the LDP manuals
(such as the Installation and Getting Started Guide) with their
software. The LDP manuals are intended to be used as the "official"
Linux documentation, and we'd like to see mail-order distributors
bundling the LDP manuals with the software. As the LDP manuals mature,
hopefully they will fulfill this goal more adequately.
Matt Welsh, [EMAIL PROTECTED]
------------------------------
** FOR YOUR REFERENCE **
The service address, to which questions about the list itself and requests
to be added to or deleted from it should be directed, is:
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You can send mail to the entire list (and comp.os.linux.misc) via:
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Linux may be obtained via one of these FTP sites:
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End of Linux-Misc Digest
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