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<articleinfo>
<title>The Linux FAQ</title>
<author>
<firstname>David</firstname>
<othername>C.</othername>
<surname>Merrill</surname>
<affiliation><address>david -AT- lupercalia.net</address></affiliation>
</author>
<authorinitials>dcm</authorinitials>
<pubdate>2003-09-19</pubdate>
<version>2.1.1</version>
<revhistory>
<revision>
<revnumber>1.20</revnumber>
<date>2001-12-04</date>
<authorinitials>rk</authorinitials>
</revision>
<revision>
<revnumber>2.0</revnumber>
<date>2002-04-25</date>
<authorinitials>dcm</authorinitials>
<revremark>Some reorganization and markup changes.</revremark>
</revision>
<revision>
<revnumber>2.1</revnumber>
<date>2003-05-19</date>
<authorinitials>dcm</authorinitials>
<revremark>Fairly complete reorganization and conversion to WikiText.</revremark>
</revision>
<revision>
<revnumber>2.1.1</revnumber>
<date>2003-09-19</date>
<authorinitials>dcm</authorinitials>
<revremark>Minor corrections.</revremark>
</revision>
<revision>
<revnumber>2.1.2</revnumber>
<date>2004-02-28</date>
<authorinitials>dcm</authorinitials>
<revremark>Minor corrections.</revremark>
</revision>
</revhistory>
<abstract>
<para>This is the list of Frequently Asked Questions for Linux,
the Free/Open Source UNIX&trade;-like operating system kernel that runs on many
modern computer systems.
</para>
</abstract>
</articleinfo>
=Introduction|intro=
==About the FAQ==
This document contains a collection of the answers to the most common questions
people ask about Linux.
It is available as WikiText source, DocBook XML, an ASCII text file, an HTML World Wide
Web page, Postscript, PDF, Plucker, and as a USENET news posting.
DocBook XML is generated from WikiText source using
[[http://tldp.org/downloads|<command>wt2db</command>]].
HTML is generated from the XML using the LDP's XSL customization layer on top of
[[http://docbook.sf.net|Norm Walsh's standard DocBook XSL stylesheets]].
Text is generated from the HTML using <command>lynx</command>.
Most of these programs are found in most Linux distributions.
The Usenet version is posted regularly to
[[news:news.answers]], [[news:comp.answers]],
and [[news:comp.os.linux.misc]]. It is archived at
[[ftp://rtfm.mit.edu/pub/usenet-by-hierarchy/comp/os/linux/misc]].
The latest versions are available from the
[[http://tldp.org|Linux Documentation Project]].
==Asking Questions and Sending Comments|feedback==
If you have any comments, or if you have a question about Linux that was not
answered here, feel free to send it to the maintainer:
david -AT- lupercalia.net.
'''Place the letters FAQ in the subject of your message.'''
I won't guarantee to answer all questions, but I'll answer as many as I can.
Questions that I receive repeatedly will be added to the FAQ.
If you wish to refer to a question in the FAQ, please
include the title of the question in your email.
If you have an addition to the FAQ, by all means send it.
Contributions may be in any format, but I prefer comments in English to patch files.
Context diff is not my first language.
==Authorship and Acknowledgments|authorship-and-acknowledgments==
This FAQ is currently compiled and maintained by David Merrill,
with assistance and comments from Linux users
all over the world.
Over the years it has passed through several hands, and I'd like to
recognize all the folks who have worked on it.
In addition to those of us who have been official maintainers,
the FAQ is full of individual contributions.
The name of the contributor is listed along with the contribution.
The FAQ was maintained by Robert Kiesling until January, 2002
Freddy Contreras, [[mailto:the_blur_oc@hotmail.com]],
designed and GPL'd the Linux Frequently Asked Questions logos.
Special thanks are due to Matt Welsh, who moderated
[[news:comp.os.linux.announce]] and
[[news:comp.os.linux.answers]], coordinated the
HOWTO's and wrote substantial portions of many of them, Greg Hankins
the former Linux Documentation Project HOWTO maintainer, Lars
Wirzenius and Mikko Rauhala, the former and current moderators of
[[news: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.
Other contributors include:
*Doug Jensen [[mailto:djen@ispwest.com]]
/*
Last but not least, thanks to Linus Torvalds and the other
contributors to Linux for giving us something to talk about!
==Copyright and License|copyright==
Copyright (c) 2001 Robert Kiesling.
Copyright (c) 2002, 2003 David Merrill.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
or any later version published by the Free Software Foundation;
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts.
A copy of the license is provided in the appendix, [[link:fdl]].
The maintainer would be happy to answer any questions regarding the copyright.
Unix&trade; is a trademark of AT&amp;T Bell Laboratories.
Linux is a trademark of Linus Torvalds.
Other trademarks belong to their holders.
==Disclaimer|disclaimer==
While every attempt has been made to provide accurate and helpful
information, I make no promises or guarantees of any kind.
Use this information at your own risk.
=General Information|general=
Q: What Is Linux?|what-is-linux
A: The name "Linux" is used to refer to three similar yet slightly different things,
which can be confusing to all but the hardcore geek.
The three usages vary by how much of a complete software system the speaker is talking about.
At the lowest level, every Linux system is based on the '''Linux kernel'''
&mdash; the very low-level software that manages your computer hardware,
multi-tasks the many programs that are running at any given time, and other
such essential things.
These low-level functions are used by other programs, so their authors can
focus on the specific functionality they want to provide.
Without the kernel, your computer is a very expensive doorstop.
It has all of the features of a modern operating system: true multitasking,
threads, virtual memory, shared libraries, demand loading, shared, copy-on-write
executables, proper memory management,
loadable device driver modules, video frame buffering, and TCP/IP networking.
Most often, the name "Linux" is used to refer to the '''Linux Operating System'''.
An OS includes the kernel, but also adds various utilities &mdash; the kinds of programs
you need to get anything done.
For example, it includes a '''shell''' (the program that provides a command prompt and lets you run programs),
a program to copy files, a program to delete files, and many other odds and ends.
Some people honor the request of Richard Stallman and the [[http://www.gnu.org|GNU Project]],
and call the Linux OS '''GNU/Linux''', because a good number of these utility programs were written by the GNU folks.
Finally, software companies (and sometimes volunteer groups) add on lots of extra software, like the
[[http://www.xfree86.org|XFree86 X Window System]], [[http://www.gnome.org|Gnome]],
[[http://www.kde.org|KDE]], games and many other applications.
These software compilations which are based on the Linux OS are called '''Linux distributions'''.
So, there are three Linuxes: the Linux kernel, the Linux OS, and the various Linux distributions.
Most people, however, refer to the operating system kernel, system software,
and application software, collectively, as "Linux", and that convention is
used in this FAQ as well.
See also the Wikipedia articles on the
[[wiki:Linux kernel]] and the [[wiki:Linux operating system]].
Q: Is Linux Unix?|is-linux-unix
A: Officially an operating system is not allowed to be called a Unix until it
passes the Open Group's certification tests, and supports the necessary API's.
Nobody has yet stepped forward to pay the large fees that certification
involves, so we're not allowed to call it Unix.
Certification really doesn't mean very much anyway.
Very few of the commercial operating systems have passed the Open Group tests.
A: Unofficially, Linux is very similar to the operating systems which are known
as Unix, and for many purposes they are equivalent.
Linux the kernel is an operating system kernel that behaves and performs similarly
to the famous Unix operating system from AT&amp;T Bell Labs.
Linux is often called a "Unix-like" operating system.
For more information, see [[http://www.unix-systems.org/what_is_unix.html]].
[Bob Friesenhahn]
Q: Who Wrote Linux?|who-wrote-linux
A: Linus Torvalds and a loosely knit team of volunteer hackers from across
the Internet wrote (and still are writing) Linux from scratch.
Q: How Is Linux Licensed?|is-linux-public-domain-copyrighted
A: Linus has placed the Linux kernel
under the GNU General Public License, which basically means that you may
freely copy, change, and distribute it, but you may not impose any
restrictions on further distribution, and you must make the source code
available.
This is not the same as Public Domain. See the Copyright FAQ,
[[ftp://rtfm.mit.edu/pub/usenet/news.answers/law/copyright]],
for details.
Full details are in the file [[COPYING]] in the Linux kernel
sources (probably in [[/usr/src/linux]] on your system).
There is a FAQ for the GPL at: [[http://www.gnu.org/copyleft/gpl-faq.html]].
The licenses of the utilities and programs which come with the installations
vary. Much of the code is from the GNU Project at the Free Software
Foundation, and is also under the GPL. Some other major programs often included
in Linux distributions are under a BSD license and other similar licenses.
Note that discussion about the merits or otherwise of the GPL should be
posted to the news group gnu.misc.discuss, and not to the
[[news:comp.os.linux]] hierarchy.
For legal questions, refer to the answer:
[[link:where-are-linux-legal-issues-discussed]].
Q: How Does One Pronounce Linux?|pronounce-linux
A: This question produces an outrageous amount of heated debate.
If you want to hear Linus himself say how he pronounces it, download [[english.au]] or
[[swedish.au]] from [[ftp://ftp.funet.fi/pub/Linux/PEOPLE/Linus/SillySounds/]].
If you have a sound card or the PC-speaker audio driver you can hear them by
typing
<screen> $ cat english.au >/dev/audio </screen>
The difference isn't in the pronunciation of Linux but in the language
Linus uses to say, "hello".
For the benefit of those who
don't have the equipment or inclination: Linus pronounces Linux approximately
as '''Leenus''', where the '''ee''' is pronounced as in "feet," but rather shorter,
and the '''u''' is like a much shorter version of the French '''eu''' sound in
'''peur''' (pronouncing it as the '''u''' in "put" is probably passable).
Q: How Many People Use Linux?|how-many-people
A: Linux is freely available, and no one is required to
register with any central authority, so it is difficult to know.
Several businesses survive solely on selling and supporting Linux.
Linux newsgroups are some of the most heavily read on Usenet.
Accurate numbers are hard to come by, but the number is almost certainly in the millions.
However, people can register as Linux users at the Linux Counter project,
which has been in existence since 1993. In May of 2003 the project counted
more than 134,000 users, but that is certainly only a small fraction of all users.
The operator of the Linux Counter estimated 18 million users, as of May 2003.
Visit the Web site at [[http://counter.li.org/]] and fill in the registration form.
The current count is posted monthly to
[[news:comp.os.linux.misc]], and is always available from the
Web site.
[Harald Tveit Alvestrand]
A: In 1999, International Data Corporation released its
first commercial forecast of Linux sales. The report quantifies Linux vendor
sales in 1996, 1997, and 1998, and forecasts through the year 2003.
To obtain the report, contact IDC at [[mailto:ctoffel@idc.com]].
Their Web site is [[http://www.itresearch.com/]].
=The Linux Kernel|kernel=
Q: What Platforms Does Linux Support?|platform-support
A: Linux runs on almost every general-purpose computer made in the
last 10 years. It runs on systems as small as PDAs (for example,
the Sharp Zaurus) and on systems as large as IBM mainframes.
There are Linux distributions specifically for mobile and handheld platforms.
Information on the Linux distribution for the Compaq iPAQ is at [[http://www.handhelds.org]].
A: Linux was written originally for Intel processor based PC's,
using the hardware facilities of the 80386 processor and its successors to implement its features.
The 80386 family includes the 80486 and all of the Pentium chips.
However, there are now many ports to other hardware platforms.
See [[link:what-ports-to-other-processors-are-there]].
Refer also to the Linux <citetitle>INFO-SHEET</citetitle> for more details as
well as the answers to
[[link:howtos-and-other-documentation]],
[[link:does-linux-run-on-my-computer]], and
[[link:what-ports-to-other-processors-are-there]], below.
Q: What Hardware Is Supported?|does-linux-run-on-my-computer
A: A minimal Linux installation requires a machine for which a port exists,
at least 2Mb of RAM, and a single floppy drive, but to do anything even
remotely useful, more RAM and disk space are needed. Refer to:
[[link:what-ports-to-other-processors-are-there]],
[[link:how-much-hard-disk-space-does-linux-need]], and
[[link:how-much-memory-does-linux-need]].
Intel CPU, PC-compatible machines require at least an 80386 processor to run
the standard Linux kernel.
Linux, including the X Window System GUI, runs on most current laptops. Refer
to the answer for: [[link:my-notebook-runs-linux]].
There are numerous sources of information
about specific PC's, video cards, disk controllers, and other hardware. Refer
to the [[ldp:INFO-SHEET]], [[ldp:Laptop-HOWTO]],
and the [[ldp:Unix-Hardware-Buyer-HOWTO]].
See [[link:howtos-and-other-documentation]].
Q: Ports to Other Processors|what-ports-to-other-processors-are-there
A: Ports are currently available for:
*[[http://www.linuxalpha.org|Compaq Alpha AXP]]
*[[http://www.ultralinux.org|Sun SPARC and UltraSPARC]]
*[[http://www.linux-m68k.org|Motorola 68000]]
*[[http://penguinppc.org|PowerPC]]
*[[http://linuxppc64.org|PowerPC64]]
*[[http://www.arm.linux.org|ARM]]
*[[http://linuxsh.sourceforge.net|Hitachi SuperH]]
*[[http://www.ibm.com/s390/linux|IBM zSeries and S/390]]
*[[http://www.linux-mips.org|MIPS]]
*[[http://www.parisc-linux.org|HP PA-RISC]]
*[[http://www.linuxia64.org|Intel IA-64]]
*[[http://linux-vax.sourceforge.net|DEC VAX]]
*[[http://www.x86-64.org|AMD x86-64]]
*[[http://developer.axis.com/software/linux|CRIS]]
/*
A: There are always efforts underway to port Linux onto new processors.
Linux Online maintains a
[[http://www.linux.org/projects/ports.html:list of ports currently in development]].
In addition, the following information is available about specific ports:
On Intel platforms, VESA Local Bus and PCI bus are supported.
MCA (IBM's proprietary bus) and ESDI hard drives are mostly supported. There
is further information on the MCA bus and what cards Linux supports on the
Micro Channel Linux Web page, [[http://www.dgmicro.com/mca]]. Refer also to
the answer for: [[link:world-wide-web-for-linux-stuff]].
There is a port of Linux to the 8086, known as the Embeddable Linux Kernel
Subset (ELKS). This is a 16-bit subset of the Linux kernel which will mainly
be used for embedded systems, at: [[http://www.linux.org.uk/Linux8086.html]].
Standard Linux does not run 8086 or 80286 processors, because it requires
task-switching and memory management facilities found on 80386 and later
processors.
Linux supports multiprocessing with Intel MP architecture. See the file
[[Documentation/smp.tex]] in the Linux kernel source code distribution.
An API specification and developers kit for the Crusoe Smart Microprocessor developed
by Transmeta Corporation are at [[http://www.transmeta.com]].
A project has been underway for a while to port Linux to suitable
68000-series based systems like Amigas and Ataris. The Linux/m68K FAQ is
located at [[http://www.clark.net/pub/lawrencc/linux/faq/faq.html]]. The URL
of the Linux/m68k home page is [[http://www.linux-m68k.org/faq/faq.html]].
There is also a linux-680x0 mailing list.
See [[link:what-mailing-lists-are-there]].
There is (or was) a FTP site for the Linux-m68k project on
[[ftp://ftp.phil.uni-sb.de/pub/atari/linux-68k]], but this address may no longer be
current.
Debian GNU/Linux has ports to Alpha, Sparc, Motorola 68k, PowerPC, ARM,
IBM S/390, MIPS, HP PA-RISC, and IA-64.
A Port to amd64 is being developed.
There are mailing lists for all of them.
See [[http://www.debian.org/MailingLists/]] for general information, then follow
the "subscription" link, and find the mailing list you are interested in.
One of the Linux-PPC project pages is [[http://www.linuxppc.org]],
and the archive site is [[ftp://ftp.linuxppc.org/linuxppc]].
There are two sites for the Linux iMac port:
[[http://w3.one.net/~johnb/imaclinux]], and
[[http://www.imaclinux.net:8080/content/index.html]].
A port to the 64-bit DEC Alpha/AXP is at
[[http://www.azstarnet.com/~axplinux/]]. There is a mailing list at
<literal>vger.redhat.com</literal>: see [[link:what-mailing-lists-are-there]].
Ralf Baechle is working on a port to the MIPS, initially for the R4600 on
Deskstation Tyne machines. The <citetitle>Linux-MIPS</citetitle> FTP sites
are [[ftp://ftp.fnet.fr/linux-mips]] and
[[ftp://ftp.linux.sgi.com/pub/mips-linux]]. Interested people may mail their
questions and offers of assistance to [[mailto:linux@waldorf-gmbh.de]].
There is (or was) also a MIPS channel on the Linux Activists mail server and
a linux-mips mailing list. See [[link:what-mailing-lists-are-there]].
There are currently two ports of Linux to the ARM family of processors. One
of these is for the ARM3, fitted to the Acorn A5000, and it includes I/O
drivers for the 82710/11 as appropriate. The other is to the ARM610 of the
Acorn RISC PC. The RISC PC port is currently in its early to middle stages,
owing to the need to rewrite much of the memory handling. The A5000 port is
in restricted beta testing. A release is likely soon.
For more, up-to-date information, read the newsgroup
[[news:comp.sys.acorn.misc]].
There is a FAQ at [[http://www.arm.uk.linux.org]].
The Linux SPARC project is a hotbed of activity. There is a FAQ and plenty of
other information available from the UltraLinux page,
[[http://www.ultralinux.org]].
The Home Page of the UltraSPARC port ("UltraPenguin") is located at
[[http://sunsite.mff.cuni.cz/linux/ultrapenguin-1.0/]], although the URL may
not be current.
There is also a port to SGI/Indy machines ("Hardhat"). The URL is
[[http://www.linux.sgi.com]].
Q: How Does Linux Kernel Versioning Work?|linux-versioning
A: At any given time, there are several "stable" versions of Linux, and one
"development" version. Unlike most proprietary software, older stable versions
continue to be supported for as long as there is interest, which is why multiple versions exist.
Linux version numbers follow a longstanding tradition. Each version has three numbers,
i.e., X.Y.Z. The "X" is only incremented when a really significant change happens,
one that makes software written for one version no longer operate correctly on the other.
This happens very rarely -- in Linux's history it has happened exactly once.
The "Y" tells you which development "series" you are in. A stable kernel will
always have an even number in this position, while a development kernel will
always have an odd number.
The "Z" specifies which exact version of the kernel you have, and it is
incremented on every release.
The current stable series is 2.4.x, and the current development series is 2.5.x.
However, many people continue to run 2.2.x and even 2.0.x kernels, and they als
o continue to receive bugfixes. The development series is the code that the Linu
x developers are actively working on, which is always available for public
viewing, testing, and even use, although production use is not recommended!
This is part of the "open source development" method.
Eventually, the 2.5.x development series will be "sprinkled with holy penguin
pee" and become the 2.6.0 kernel and a new stable series will then be established,
and a 2.7.x development series begun. Or, if any really major changes happen,
it might become 3.0.0 instead, and a 3.1.x series begun.
Q: Where Is the Latest Kernel Version on the Internet?|where-can-i-get-the-latest-kernel-version
A: The easiest way to update your kernel is to get the update directly
from the distribution which you are running.
A: If you need or want to configure and compile your own kernel, the web page at
[[http://www.kernel.org/]] lists the current versions of the development and production kernels.
If you want to download the source code, FTP to
<literal>ftp.xx.kernel.org</literal>, where <literal>xx</literal> is the
two-letter Internet domain abbreviation of your country; e.g.,
<literal>us</literal> for United States, <literal>ca</literal> for
Canada, or <literal>de</literal> for Germany. Kernel versions 2.2.x are
archived in the directory [[pub/linux/kernel/v2.2]], as are
patches for the prerelease versions. The kernel source code is archived as a
<literal>.tar.gz</literal> file, and as a <literal>.tar.bz2</literal> file.
Follow the instructions in any of the standard references to compile the
kernel, as you would with any other custom kernel. The
[[Documentation]] subdirectory contains information by the
authors of various subsystems and drivers, and much of that information is
not documented elsewhere.
If you want to participate in kernel development, make sure that you sign on
to the linux-kernel mailing list to find out what people are working on.
Refer to the answer: [[link:what-mailing-lists-are-there]].
There is a story about the features of the 2.4 series kernels at
[[http://features.linuxtoday.com/stories/8191.html]].
Q: Does Linux Support Threads or Lightweight Processes?|threads-or-lightweight-processes
A: As well as the Unix multiprocessing model involving heavyweight processes, which is of course
part of the standard Linux kernel, there are several implementations of
lightweight processes or threads. Recent kernels implement a thread model,
kthreads. In addition, there are the following packages available for Linux.
*GNU glibc2 for Linux has optional support for threads.
The archive is available from the same place as glibc2, [[ftp://ftp.gnu.org/pub/gnu/]]
*In [[ftp://sipb.mit.edu/pub/pthread/]] or [[ftp://ftp.ibp.fr:/pub/unix/threads/pthreads]].
Documentation isn't in the package, but is available on the World Wide Web at
[[http://www.mit.edu:8001/people/proven/home_page.html]].
Newer Linux libc's contain the pthreads source. The GNU Ada compiler on
[[ftp://metalab.unc.edu/pub/Linux/devel/lang/ada/]]
contains binaries made from that source code.
*In [[ftp://ftp.cs.washington.edu/pub/qt-001.tar.Z]] is QuickThreads.
More information can be found in the technical report,
available on the same site is [[/tr/1993/05/UW-CSE-93-05-06.PS.Z.]]
*In [[ftp://ftp.cs.fsu.edu/pub/PART/]], an Ada
implementation. This is useful mainly because it has a lot of Postscript
papers that you'll find useful in learning more about threads. This is not
directly usable under Linux.
/*
Please contact the authors of the packages in question for details.
Q: What Version of Linux and What Machine Name Is This?|version-of-linux-and-what-machine
A: Type:
<screen> $ uname -a </screen>
Q: What is a BogoMip?|bogomip
A: "BogoMips" is a combination of '''Bogus''' and
'''Mips'''. MIPS stands for (depending on who you ask)
'''Millions of Instructions per Second''', or
'''Meaningless Indication of Processor Speed'''.
The number printed at boot time is the result of a kernel timing
calibration, used for very short delay loops by some device drivers.
According to the <citetitle>BogoMips mini-HOWTO</citetitle>, the
rating for your machine will be:
<screen>
Common BogoMips Ratings
Processor BogoMips Comparison
--------- -------- ----------
Intel 8088 clock * 0.004 0.02
Intel/AMD 386SX clock * 0.14 0.8
Intel/AMD 386DX clock * 0.18 1 (definition)
Motorola 68030 clock * 0.25 1.4
Cyrix/IBM 486 clock * 0.34 1.8
Intel Pentium clock * 0.40 2.2
Intel 486 clock * 0.50 2.8
AMD 5x86 clock * 0.50 2.8
Mips R4000/R4400 clock * 0.50 2.8
Nexgen Nx586 clock * 0.75 4.2
PowerPC 601 clock * 0.84 4.7
Alpha 21064/21064A clock * 0.99 5.5
Alpha 21066/21066A clock * 0.99 5.5
Alpha 21164/21164A clock * 0.99 5.5
Intel Pentium Pro clock * 0.99 5.5
Cyrix 5x86/6x86 clock * 1.00 5.6
Intel Pentium II/III clock * 1.00 5.6
Intel Celeron clock * 1.00 5.6
Mips R4600 clock * 1.00 5.6
Alpha 21264 clock * 1.99 11.1
AMD K5/K6/K6-2/K6-III clock * 2.00 11.1
UltraSparc II clock * 2.00 11.1
Pentium MMX clock * 2.00 11.1
PowerPC 604/604e/750 clock * 2.00 11.1
Motorola 68060 clock * 2.01 11.2
Motorola 68040 Not enough data (yet).
AMD Athlon Not enough data (yet).
IBM S390 Not enough data (yet).
</screen>
If the number is wildly lower, you may have the Turbo button or CPU speed set incorrectly,
or have some kind of caching problem (as described in
[[link:add-memory-system-slows]]).
For values people have seen with other, rarer, chips, or to
calculate your own BogoMips rating, please refer to the <citetitle>BogoMips
Mini-HOWTO</citetitle>, on [[ftp://metalab.unc.edu/]].
See [[link:howtos-and-other-documentation]].
[Wim van Dorst]
Q: Does Linux Support USB Devices?|does-linux-support-the-usb-bus
A: Linux supports a few dozen USB devices at present,
and work is underway to develop additional device drivers.
There is a Web page devoted to the subject, at
[[http://www.linux-usb.org]]. There is also LDP documentation, at:
[[link:world-wide-web-for-linux-stuff]].
Support for USB version 2.0 was recently added to development kernels, but is
not yet available in the 2.4 series.
Q: Can Linux Use More than 3 Serial Ports by Sharing Interrupts?|serial-ports-by-sharing
A: Yes, but you won't be able to use simultaneously two ordinary ports which share an interrupt
(without some trickery). This is a limitation of the ISA Bus architecture.
See the <citetitle>Serial HOWTO</citetitle> for information
about possible solutions and workarounds for this problem.
=Disk Drives|disk-drives=
Q: Does Linux Support SCSI Drives?|scsi-support==
A: Coming soon...
Q: Does Linux Support IDE Drives?|ide-support==
A: Coming soon...
Q: Does Linux Support CD-ROM Drives?|cd-rom-support
A: Coming soon...
Q: Does Linux Support DVD Drives?|dvd-support
A: Coming soon...
Q: Why Doesn't the AHA1542C Card Work With Linux?|AHA1542C-doesnt-work
A: The option to allow disks with more than 1024 cylinders, which the AHA1542C card can recognize, is only required as a workaround for a PC-compatible BIOS misfeature and should be turned off under Linux. For older Linux kernels you need to turn off most of the advanced BIOS options all but the one about scanning the bus for bootable devices.
Q: How Can I Get Linux to Work With My Disk?|linux-to-work-with-my-disk
A: If your disk is an IDE or EIDE drive, you should
read the file [[/usr/src/linux/drivers/block/README.ide]]
(part of the Linux kernel source code). This [[README]]
contains many helpful hints about IDE drives. Many modern IDE controllers do
translation between "physical" cylinders/heads/sectors, and "logical" ones.
SCSI disks are accessed by linear block numbers. The BIOS
invents some "logical" cylinder/head/sector fiction to support DOS.
Older IBM PC-compatible BIOS's will usually not be able to access
partitions which extend beyond 1024 logical cylinders, and will make booting
a Linux kernel from such partitions using LILO problematic at best.
You can still use such partitions for Linux or other operating systems
that access the controller directly.
It's recommend that you
create at least one Linux partition entirely under the 1024 logical cylinder
limit, and boot from that. The other partitions will then be okay.
Also there seems to be a bit of trouble with the newer Ultra-DMA
drives. I haven't gotten the straight scoop on thembut they are becoming a
very common problem at the SVLUG installfests. When you can get 8 to 12 Gig
drives for $200 to $300 it's no wonder.
[Jim Dennis]
=Partitions And Filesystems|partitions=
Q: Does Linux Support Virtualized File Systems Like RAID?|virtualized-file-systems-like-raid
A: The most recent Linux kernels support software RAID, and they will work with RAID disk
controllers.
An automounter for NFS partitions is part of most
Linux distributions.
In addition, several virtual file system
projects exist. One of them, the <citetitle>Linux Logical Volume
Manager</citetitle>, is located at [[http://linux.msede.com/lvm/]].
Q: Can Linux Use the Same Hard Drive as MS-DOS? OS/2? 386BSD? Win95?|can-linux-share-my-disk-with-dos
A: Yes. Linux supports many, many filesystems, including the standard MS-DOS partitioning scheme, so it can share your disk with other operating systems.
Linux supports all known versions of the Microsoft FAT and VFAT file systems,
including those used by Windows 95, Windows 98, Windows NT, Windows 2000 and Windows ME through loadable kernel modules. In a correctly configured system, they should load automatically when the partitions are mounted.
Note, however, that many other operating systems may not be exactly
compatible. DOS's [[FDISK.EXE]] and
[[FORMAT.EXE]], for example, can overwrite data in a Linux
partition, because they sometimes incorrectly use partition data from the
partition's boot sector rather than the partition table.
In order to prevent programs from doing this, it is a good idea to zero
out under Linux the start of a partition you created, before you use
MS-DOS or whatever to format it. Type:
<screen> $ dd
if=/dev/zero of=/dev/hdXY bs=512 count=1</screen>
where '''hdXY''' is the relevant partition; e.g.,
[[/dev/hda1]] for the first partition of the first (IDE)
disk.
Linux can read and write the files on your DOS and OS/2
FAT partitions and floppies using either the DOS file system type built into
the kernel or <command>mtools</command>.
There is reportedly a GPL'd OS/2
device driver that will read and write Linux ext2 partitions.
For information about FAT32 partition support, see
[[http://bmrc.berkeley.edu/people/chaffee/fat32.html]].
See [[link:what-software-does-linux-support]] for details and status of the
emulators for DOS, MS Windows, and System V programs.
See also, "Can Linux access Amiga file systems?", "Can Linux access Macintosh
file systems?", "Can Linux access BSD, SysV, etc., UFS?", and "Can Linux
access SMB file systems?"
There are said to be NTFS drivers under development, which should support compression
as a standard feature.
Q: How Do I Access Files on a MS-DOS Partition or Floppy?|how-do-i-access-files-on-my-dos-partition
A: Use the DOS file system, type, for example:
<screen> $ mkdir /dos $
mount -t msdos -o conv=text,umask=022,uid=100,gid=100 /dev/hda3 /dos</screen>
If it's a floppy, don't forget to <command>umount</command> it before ejecting it!
You can use the
<literal>conv=text/binary/auto</literal>, <literal>umask=nnn</literal>,
<literal>uid=nnn</literal>, and <literal>gid=nnn</literal> options to control
the automatic line-ending conversion, permissions and ownerships of the files
in the DOS file system as they appear under Linux. If you mount your DOS file
system by putting it in your [[/etc/fstab]], you can record
the options (comma-separated) there, instead of defaults.
Alternatively, you can use mtools, available in both binary and source form
on the FTP sites. See [[link:get-linux-material-by-ftp]].
A kernel patch (known as the fd-patches) is available which allows floppies
with nonstandard numbers of tracks and/or sectors to be used; this patch is
included in the 1.1 alpha testing kernel series.
Q: Does Linux Support Compressed Ext2 File Systems?|support-compressed-ext2-file-systems
A: The <literal>ext2compr</literal> project provides a kernel patch Information
about them is located at [[http://e2ompr.memalpha.cx/e2compr/]].
There is also a Web site for the e2compr patches. The code is still
experimental and consists of patches for the 2.0 and 2.1 kernels. For more
information about the project, including the latest patches, and the address
of the mailing list, look up the URL at [[http://debs.fuller.edu/e2compr/]].
[Roderich Schupp, Peter Moulder
A: <citetitle>zlibc</citetitle> is a program that allows existing applications
to read compressed (GNU gzip'ed) files as if they were not compressed. Look
at [[ftp://metalab.unc.edu/pub/Linux/libs/]]. The author
is Alain Knaff.
A: There is also a compressing block device
driver, "DouBle," by Jean-Marc Verbavatz, which can provide on-the-fly disk
compression in the kernel. The source-only distribution is located at
[[ftp://metalab.unc.edu/pub/Linux/patches/diskdrives/]].
This driver compresses inodes and directory information as well as
files, so any corruption of the file system is likely to be serious.
A: There is also a package called tcx (Transparently Compressed
Executables), which allows you to keep infrequently used executables
compressed and only uncompress them temporarily when in use. It is located at
[[ftp://metalab.unc.edu/pub/Linux/utils/compress/]].
Q: Can Linux Use Stacked/DBLSPC/Etc. DOS Drives?|can-i-use-my-stacked
A: Until recently, not very
easily. You can access DOS 6.X volumes from the DOS emulator ("What software
does Linux support? "), but it's harder than accessing a normal DOS volume
via the DOS kernel option, a module, or mtools.
There is a
recently added package, dmsdos, that reads and writes compressed file systems
like DoubleSpace/DriveSpace in MS-DOS 6.x and Win95, as well as Stacker
versions 3 and 4. It is a loadable kernel module. Look at
[[ftp://metalab.unc.edu/pub/Linux/system/filesystems/dosfs/]].
Q: Can Linux Access OS/2 HPFS Partitions?|can-i-access-os2-hpfs
A: Yes, but Linux access to HPFS partitions is
read-only. HPFS file system access is available as an option when compiling
the kernel or as a module. See the
[[Documentation/filesystems/hpfs.txt]] file in the kernel
source distribution. See [[link:upgrade-recompile-kernel]].
Then you can mount HPFS partition, using, for example:
<screen> $ mkdir /hpfs $ mount -t hpfs
/dev/hda5 /hpfs</screen>
Q: Can Linux Access Amiga File Systems?|can-linux-access-amiga-file-systems
A: The Linux kernel has support
for the Amiga Fast File System (AFFS) version 1.3 and later, both as a
compile-time option and as a module. The file
[[Documentation/filesystems/affs.txt]] in the Linux kernel
source distribution has more information.
See [[link:upgrade-recompile-kernel]].
Linux supports AFFS hard-drive partitions only. Floppy access
is not supported due to incompatibilities between Amiga floppy controllers
and PC and workstation controllers. The AFFS driver can also mount disk
partitions used by the Un*x Amiga Emulator, by Bernd Schmidt.
Q: Can Linux Access BSD, SysV, Etc. UFS?|can-linux-access-bsd-sysv
A: Recent kernels can mount (read only) the
UFS file system used by System V; Coherent; Xenix; BSD; and derivatives like
SunOS, FreeBSD, NetBSD, and NeXTStep. UFS support is available as a kernel
compile-time option and a module.
See [[link:upgrade-recompile-kernel]].
Q: Can Linux Access MacIntosh File Systems?|can-linux-access-macintosh-file-systems
A: There is a set of user-level programs that read and write the older Macintosh Hierarchical File
System (HFS). It is available at
[[metalab.unc.edu/pub/Linux/utils/disk-management/]].
Access to the newer, HFS+ file systems is still under development.
Q: How Do I Create a File System on a Floppy?|create-file-system-on-a-floppy
A: If you are running recent Gnome or KDE desktops, you have a GUI tool that makes formatting floppies easy.
A: To format a 3.5-inch, high density floppy at the command prompt:
<screen> $ fdformat /dev/fd0H1440
$ mkfs -t ext2 -m 0 /dev/fd0H1440 1440</screen>
For a 5.25 inch floppy, use [[/dev/fd0h1200]] and 1200 as appropriate.
For the [[B:]] drive use [[/dev/fd1]]
instead of [[/dev/fd0]].
The <command>-m 0</command> option tells <application>mkfs.ext2</application>
not to reserve any space on the
disk for the superuserusually the last 10% is reserved for root.
The first command performs a low-level format. The second creates an
empty file system. You can mount the floppy like a hard disk partition and
simply <command>cp</command> and <command>mv</command> files, etc.
Device naming conventions generally are the same as for other unices.
They can be found in Matt Welsh's <citetitle>Installation and Getting
Started</citetitle> guide. Refer to [[link:howtos-and-other-documentation]].
A more detailed and technical
description is <citetitle>Linux Allocated Devices</citetitle> by H. Peter
Anvin, [[mailto:hpa@zytor.com]],
which is included in LaTeX and ASCII form in the kernel source distribution
(probably in [[/usr/src/kernel/Documentation/]]), as
[[devices.tex]] and [[devices.txt]].
Q: Does Linux Support File System Encryption?|support-file-system-encryption
A: Yes. One file system, ppdd, is archived at [[http://pweb.de.uu.net/flexsys.mtk/]].
Q: How Do I Resize a Partition Non-Destructively?|resize-a-partition-non-destructively
A: Use the <command>FIPS.EXE</command> program, included with most Linux
distributions,under MS-DOS.
A: GNU <command>parted</command>, a partition editor, is stable enough for non-guru, mere-mortal use with
relative confidence. Source code for the latest version is at: [[ftp://ftp.gnu.org/pub/gnu/parted/]]. There's also a
boot disk image for resizing root partitions and for running <command>parted</command>
on non-Linux machines. The disk image may be easier
for beginners. Building from source could require some extra configuration.
Parted also has tutorial-style, plain-text documentation for
Linux and FAT (MS-DOS) file systems.
A: Also, some commercial distributions come with their own partitioning software,
like <application>Partition Magic</application>.
Q: Where Is the Journalling File System on the Net?|find-the-journalling-file-system
A: Linux actually supports several journalling file systems. ext3 is now included in current 2.4.x kernels.
A: The journalling file system named <application>Reiserfs</application> has just been released from testing. It is said to make Linux even faster than Linux with the
<application>Ext2</application> file system installed, particularly when dealing with many small files.
Complete information is available at [[http://devlinux.org/namesys/]].
A: JFS is still under development.
Q: Why Isn't My Virtual Memory Swap Area Working?|swap-area-isnt-working
A: When you boot (or enable swapping manually) you should see
<screen> Adding Swap: NNNNk swap-space</screen>
If you don't see any messages at all you are probably missing
<screen> swapon -av </screen>
(the command to enable swapping) in your [[/etc/rc.local]] or
[[/etc/rc.d/*]] (the system
startup scripts), or have forgotten to make the right entry in [[/etc/fstab]]:
<screen> /dev/hda2 none swap
sw </screen>
for example.
If you see:
<screen> Unable to find swap-space signature</screen>
you have forgotten to run <command>mkswap</command>. See the manual page for
details; it works much like <command>mkfs</command>.
Running the command <command>free</command>, in addition to showing free memory, should display:
<screen> total used free Swap: 10188 2960 7228</screen>
If typing <literal>cat /proc/swaps</literal> reveals only file or
partition names, but no swap space information, then the swap file or
partition needs re-initialization.
Use <command>fdisk</command> (as root) to determine which partition on a hard
drive has been designated as the swap partition. The partition still needs to
be initialized with <command>mkswap</command> before enabling it with
<command>swapon</command>.
[Andy Jefferson, Steve Withers]
Q: How Do I Add Temporary Swap Space?|add-temporary-swap-space
A: In addition to a swap partition, Linux
can also use a swap file. Some programs, like <application>g++</application>,
can use huge amounts of virtual memory, requiring the temporary creation of
extra space. To install an extra 64 MB of swap space, for example, use the
following shell commands:
<screen># dd if=/dev/zero of=/swap bs=1024 count=65535
# mkswap /swap
# swapon /swap</screen>
The <command>count=</command> argument to <command>dd</command> determines how
big the swap file will be. In this example the swap file's name is
[[/swap]], but the name and location are, generally,
arbitrary, depending only on the file system's available space and your
having write permissions in the directory.
When you don't need the swap space any more, remove it with the following statements:
<screen># swapoff /swap
# rm /swap</screen>
Take a look also at the <citetitle>Installation HOWTO</citetitle> and
<citetitle>Installation &amp; Getting Started</citetitle> for detailed
instructions.
If that still doesn't provide enough swap space,
refer to [[link:more-than-128mb-of-swap]].
=System Libraries|system-libraries=
Q: Where Can I Find Linux System Specifications?|linux-standards
A: As a start, look at the Linux Standards Base,
[[http://www.linuxbase.org]]. The site contains
information about test software, file system organization, and shared library
naming conventions.
Q: What Is <application>ld.so</application> and How Do I Get It?|ld-so-and-where-do-i-get-it
A: <application>ld.so</application> is the dynamic library loader. Each binary
using shared libraries used to have about 3K of start-up code to find and
load the shared libraries. Now that code has been put in a special shared
library, [[/lib/ld.so]], where all binaries can look for it,
so that it wastes less disk space, and can be upgraded more easily.
<literal>ld.so</literal> can be obtained from
[[http://tsx-11.mit.edu/pub/linux/packages/GCC/]] and
mirror sites. The latest version at the time of writing is
[[ld.so.1.9.5.tar.gz]].
[[/lib/ld-linux.so.1]] is the same thing for ELF ("What's
all this about ELF? ") and comes in the same package as the
[[a.out]] loader.
Q: How Do I Upgrade the Libraries without Trashing the System?|upgrade-libraries-withough-trashing
A: <warning>You should always have a rescue disk set ready when you perform this
procedure, in the likely event that something goes wrong!</warning>
This procedure is especially difficult if you're upgrading very old
libraries like <application>libc4</application>. But you should be able to
keep <application>libc4</application> on the same system with
<application>libc5</application> libraries for the programs that still need
them. The same holds true for upgrading from <application>libc5</application>
to the newer-yet <application>glibc2</application> libraries.
The problem with upgrading dynamic libraries is that the moment you remove
the old libraries, the utilities that you need to upgrade to the new version
of the libraries don't work. There are ways around around this. One is to
temporarily place a spare copy of the run time libraries, which are in
[[/lib/]], in [[/usr/lib/]], or
[[/usr/local/lib/]], or another directory that is listed in the [[/etc/ld.so.conf]] file.
For example, when upgrading <application>libc5</application> libraries, the files in
[[/lib/]] might look something like:
<screen>libc.so.5 libc.so.5.4.33 libm.so.5 libm.so.5.0.9</screen>
These are the C libraries and the math libraries. Copy them to another
directory that is listed in [[/etc/ld.so.conf]], like
[[/usr/lib/]]:
<screen> $ cp -df /lib/libc.so.5* /usr/lib/
$ cp -df /lib/libm.so.5* /usr/lib/
$ ldconfig</screen>
Be sure to run <command>ldconfig</command> to upgrade
the library configuration.
The files [[libc.so.5]] and [[libm.so.5]] are
symbolic links to the actual library files. When you upgrade, the new links
will not be created if the old links are still there, unless you use the
<command>-f</command> flag with <command>cp</command>. The
<command>-d</command> flag to <command>cp</command> will copy the symbolic
link itself, and not the file it points to.
If you need to overwrite the link to the library directly, use the <command>-f</command>
flag with <command>ln</command>.
For example, to copy new libraries over the old ones, try this. Make a symbolic link to the new
libraries first, then copy both the libraries and the links to
[[/lib/]], with the following commands.
<screen> $ ln -sf ./libm.so.5.0.48 libm.so.5
$ ln -sf ./libc.so.5.0.48 libc.so.5
$ cp -df libm.so.5* /lib
$ cp -df libc.so.5* /lib</screen>
Again, remember to run <command>ldconfig</command> after you copy the
libraries.
If you are satisfied that everything is working
correctly, you can remove the temporary copies of the old libraries from
[[/usr/lib/]] or wherever you copied them.
Q: What's All This about ELF? glibc?|about-elf-glibc
A: See the <citetitle>ELF HOWTO</citetitle> by Daniel
Barlow. Note that this is not the file [[move-to-elf]],
which is a blow-by-blow account of how to upgrade to ELF manually.
Linux has two different formats for executables, object files, and
object code libraries, known as, "ELF". (The old format is called
"a.out".) They have advantages, including better support for shared
libraries and dynamic linking.
Both a.out and ELF binaries can coexist on a system.
However, they use different shared C libraries, both of
which have to be installed.
If you want to find out whether your system can run ELF binaries, look in [[/lib]] for a
file named, [[libc.so.5]]. If it's there, you probably
have ELF libraries. If you want to know whether your installation actually is
ELF you can pick a representative program, like <command>ls</command>, and
run file on it:
<screen> -chiark:~> file /bin/ls
/bin/ls: Linux/i386 impure executable (OMAGIC) - stripped
valour:~> file /bin/ls
/bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1, stripped </screen>
There is a patch to get 1.2.x to compile using the ELF compilers, and produce ELF core dumps, at
[[ftp://tsx-11.mit.edu/pub/packages/GCC/]]. You do not
need the patch merely to run ELF binaries. 1.3.x and later do not need the
patch at all.
The GNU glibc2 libraries are essentially more
recent versions of ELF libraries that follow most of the same processes for
dynamic linking and loading. Upgrade information is contained in
[[link:upgrade-libraries-withough-trashing]].
=Linux Distributions|linux-distributions=
Q: How Do I Get Started?|where-do-i-start
A: If you are new to Linux, you should start by buying or downloading a
general-purpose Linux distribution. A distribution is a complete operating
system, including the Linux kernel and all the utilities and software you are
likely to need, ready to install and use. Most distributions include thousands
of software packages, including user-friendly desktops, office suites, and games.
There are a handful of major Linux distributions, and as a beginner you are
probably safer using one of them. For information about them, and how they
are installed, see the [[ldp:Distributions-HOWTO]] from the Linux Documentation
Project. Also, a list of distributions is updated weekly at [[http://lwn.net]].
Before you select which distribution you want to try, read their descriptions
carefully and compare them to your needs. Each distribution is tailored to a
particular type of user. Some are optimized to function as servers, some are
optimized for gaming, and some are optimized for desktop and office use.
There are a few distributions which are considered to be outstanding choices
for new users:
*Red Hat is particularly good for servers
*Mandrake is excellent as a desktop system
*SuSE is also excellent as a desktop system
/*
There are also a large number of releases which are distributed less globally
that suit special local and national needs. Many of them are archived at
[[ftp://ftp.tux.org]].
Q: What are the Disk Space Requirements for Minimal, Server, and Workstation Use?|how-much-hard-disk-space-does-linux-need
A: Linux needs about 10Mb for a very minimal installation,
suitable for trying Linux, and not much else.
You can fit a typical server installation, including the X Window System GUI,
into 80Mb.
Installing a small Debian GNU/Linux workstation takes from 500Mb to 1GB,
including kernel source code, some space for user files, and spool areas.
Installing a commercial distribution that has a desktop GUI environment,
commercial word processor, and front-office productivity suite, will claim
15.1 GB of disk space, approximately.
A fully installed Debian GNU/Linux system could use several Gigabytes
of disk space.
Q: What are the Minimum and Maximum Memory Requirements?|how-much-memory-does-linux-need
A: Linux needs at least 4MB, and then you will need to use special installation procedures
until the disk swap space is installed. Linux will run comfortably in 4MB of
RAM, although running GUI apps is impractically slow because they need to
swap out to disk.
Some applications, like StarOffice, require 32 MB of physical memory, and
compiling C++ code can easily consume over 100 MB of combined physical and
virtual memory.
There is a distribution, "Small Linux", that will run on machines with 2MB of
RAM. Refer to the answer to: [[link:get-linux-material-by-ftp]].
A number of people have asked how to address more than 64 MB of memory, which
is the default upper limit in most standard kernels. Either type, at the
<literal>BOOT lilo:</literal> prompt:
<screen>mem=XXM</screen>
Or place the following in your [[/etc/lilo.conf]] file:
<programlisting> append="mem=XXM" </programlisting>
The parameter "'''XX'''M" is the amount of memory, specified
as megabytes; for example, "128M."
If an "<literal>append=</literal>" directive with other configuration options
already exists in [[/etc/lilo.conf]], then add the
<literal>mem=</literal> directive to the end of the existing argument, and
separated from the previous arguments by a space; e.g.:
<programlisting># Example only; do not use.
append="parport=0x3bc,none serial=0x3f8,4 mem=XXM"</programlisting>
Be sure to run the "<command>lilo</command>" command to install the new
configuration.
If Linux still doesn't recognize the extra memory, the kernel may need
additional configuration. Refer to the [[/usr/src/linux/Documentation/memory.txt]]
file in the kernel source as a start.
For further information about LILO, refer to the manual pages for
<command>lilo</command> and [[lilo.conf]], the documentation
in [[/usr/doc/lilo]], the [[ldp:LILO-HOWTO]], and the answer for:
[[link:boot-time-parameters]], below.
Q: What Is the Best Distribution, SCSI Card, Editor, CD-ROM Drive, etc?|what-is-best
A: The "best" of anything depends on your particular needs. Discussions like these
frequently occur on Usenet. Most often they're flame bait. Answering is
generally a waste of time. Free software licensing is unrestrictive enough,
that, with a little experience, you can perform your own testing on your own
hosts.
A better way to phrase a specific inquiry might be: "Where can I find...."
Q: How Can I Get a Distribution?|how-to-get-a-distro
A: If you can, please dig into your wallet and buy a copy of your distribution.
Linux distributions are extremely inexpensive - usually around $30 for a complete
system, and anywhere from $70 to around $150 for a larger system with more server
software or development tools. Even the $30 "basic" systems contain the equivalent
of thousands of dollars in proprietary tools, and are an incredible value.
The distributors invest many of your dollars into further development, and most
of them fund outside open source projects.
Commercial distributions are available from book and electronics stores,
or you can order from their websites.
If you use Debian GNU/Linux, which is a volunteer project and a non-profit,
you can donate directly to them instead.
A: There are some websites that sell Linux CD's very inexpensively. Try:
* [[http://www.cheapbytes.com]]
/*
A: Every distribution provides a download on their home page.
This is a requirement of the licensing terms of the software,
so if you cannot afford to pay for your distribution, you can get a copy this way.
Some people compromise between paying and downloading,
for example by buying each major release (such as 6.0) but downloading the
point releases (such as 6.1 and 6.2).
Also, archives of many of the distributions are on line at:
[[ftp://ftp.tux.org]] and [[http://planetmirror.com/pub/linux]].
A: Some hardware vendors now ship systems with Linux pre-installed.
However, they sometimes make it very difficult to buy them -
they offer Linux on only a few systems, which are server machines,
or they require you to go to a special "Linux" section on their website.
Q: Where Are the Linux FTP Archives?|get-linux-material-by-ftp
A: There are three main archive sites for Linux:
*[[ftp://ftp.funet.fi/pub/OS/Linux/]] (Finland).
*[[http://ibiblio.org/pub/linux/]] (US), with a nice WWW interface.
*[[ftp://tsx-11.mit.edu//pub/linux/]] (US).
/*
The best place to get the Linux kernel is
[[ftp://ftp.kernel.org/pub/linux/kernel/]]. Linus Torvalds uploads the most
recent kernel versions to this site.
Of the U.S. distributions, Debian GNU/Linux is available at
[[http://www.debian.org/distrib/]]. Red Hat Linux's home site is
[[ftp://ftp.redhat.com/]], and Linux Slackware's is
[[ftp://ftp.freesoftware.com/]].
The Small Linux distribution, which can run in 2 MB of RAM, is located at
[[http://smalllinux.netpedia.net/]].
The contents of these sites is mirrored (copied, usually approximately daily)
by a number of other sites. Please use a site close to you will be faster
for you and easier on the network.
*[[ftp://ftp.sun.ac.za/pub/linux/sunsite/]] (South Africa)
*[[ftp://ftp.is.co.za/linux/sunsite/]] (South Africa)
*[[ftp://ftp.cs.cuhk.hk/pub/Linux/]] (Hong Kong)
*[[ftp://sunsite.ust.hk/pub/Linux/]] (Hong Kong)
*[[ftp://ftp.spin.ad.jp/pub/linux/]] (Japan)
*[[ftp://ftp.nuri.net/pub/Linux/]] (Korea)
*[[ftp://ftp.jaring.my/pub/Linux/]] (Malaysia)
*[[ftp://ftp.nus.sg/pub/unix/Linux/]] (Singapore)
*[[ftp://ftp.nectec.or.th/pub/mirrors/linux/]] (Thailand)
*[[ftp://planetmirror.com/pub/linux]] (Australia) (Also take a look at [[http://planetmirror.com/archives.php]].)
*[[ftp://ftp.monash.edu.au/pub/linux/]] (Australia)
*[[ftp://ftp.univie.ac.at/systems/linux/sunsite/]] (Austria)
*[[ftp://ftp.fi.muni.cz/pub/Unix/linux/]] (Czech Republic)
*[[ftp://ftp.funet.fi/pub/Linux/sunsite/]] (Finland)
*[[ftp://ftp.univ-angers.fr/pub/Linux/]] (France)
*[[ftp://ftp.iut-bm.univ-fcomte.fr/]] (France)
*[[ftp://ftp.ibp.fr/pub/linux/sunsite/]] (France)
*[[ftp://ftp.loria.fr/pub/linux/sunsite/]] (France)
*[[ftp://ftp.dfv.rwth-aachen.de/pub/linux/sunsite/]] (Germany)
*[[ftp://ftp.germany.eu.net/pub/os/Linux/Mirror.SunSITE/]] (Germany)
*[[ftp://ftp.tu-dresden.de/pub/Linux/sunsite/]] (Germany)
*[[ftp://ftp.uni-erlangen.de/pub/Linux/MIRROR.sunsite/]] (Germany)
*[[ftp://ftp.gwdg.de/pub/linux/mirrors/sunsite/]] (Germany)
*[[ftp://ftp.rz.uni-karlsruhe.de/pub/linux/mirror.sunsite/]] (Germany)
*[[ftp://ftp.ba-mannheim.de/pub/linux/mirror.sunsite/]] (Germany)
*[[ftp://ftp.uni-paderborn.de/pub/Mirrors/sunsite.unc.edu/]] (Germany)
*[[ftp://ftp.uni-rostock.de/Linux/sunsite/]] (Germany)
*[[ftp://ftp.rus.uni-stuttgart.de/pub/unix/systems/linux/MIRROR.sunsite/]] (Germany)
*[[ftp://ftp.uni-tuebingen.de/pub/linux/Mirror.sunsite/]] (Germany)
*[[ftp://ftp.kfki.hu/pub/linux/]] (Hungary)
*[[ftp://linux.italnet.it/pub/Linux/]] (Italy)
*[[ftp://ftp.unina.it/pub/linux/sunsite/]] (Italy)
*[[ftp://giotto.unipd.it/pub/unix/Linux/]] (Italy)
*[[ftp://cnuce-arch.cnr.it/pub/Linux/]] (Italy)
*[[ftp://ftp.flashnet.it/mirror2/metalab.unc.edu/]] (Italy)
*[[ftp://ftp.nijenrode.nl/pub/linux/]] (Netherlands)
*[[ftp://ftp.LeidenUniv.nl/pub/linux/sunsite/]] (Netherlands)
*[[ftp://ftp.nvg.unit.no/pub/linux/sunsite/]] (Norway)
*[[ftp://sunsite.icm.edu.pl/pub/Linux/metalab.unc.edu/]] (Poland)
*[[ftp://ftp.rediris.es/software/os/linux/sunsite/]] (Spain)
*[[ftp://sunsite.rediris.es/software/linux/]] (Spain)
*[[ftp://ftp.cs.us.es/pub/Linux/sunsite-mirror/]] (Spain)
*[[ftp://ftp.etse.urv.es/pub/mirror/linux/]] (Spain)
*[[ftp://ftp.etsimo.uniovi.es/pub/linux/]] (Spain)
*[[ftp://ftp.luna.gui.es/pub/linux.new/]] (Spain)
*[[ftp://ftp.metu.edu.tr/pub/linux/sunsite/]] (Turkey)
*[[ftp://unix.hensa.ac.uk/mirrors/sunsite/pub/Linux/]] (UK)
*[[ftp://ftp.maths.warwick.ac.uk/mirrors/linux/sunsite.unc-mirror/]] (UK)
*[[ftp://ftp.idiscover.co.uk/pub/Linux/sunsite.unc-mirror/]] (UK)
*[[ftp://sunsite.doc.ic.ac.uk/packages/linux/sunsite.unc-mirror/]] (UK)
*[[ftp://ftp.io.org/pub/mirrors/linux/sunsite/]] (Canada)
*[[ftp://ftp.cc.gatech.edu/pub/linux/]] (US)
*[[ftp://ftp.freesoftware.com/pub/linux/sunsite/]] (US)
*[[ftp://ftp.siriuscc.com/pub/Linux/Sunsite/]] (US)
*[[ftp://ftp.engr.uark.edu/pub/linux/sunsite/]] (US)
*[[ftp://ftp.infomagic.com/pub/mirrors/linux/sunsite/]] (US)
*[[ftp://linux.if.usp.br/pub/mirror/metalab.unc.edu/pub/Linux/]] (Brazil)
*[[ftp://farofa.ime.usp.br/pub/linux/]] (Brazil)
/*
Please send updates and corrections to this list to the Linux FAQ maintainer,
see [[link:feedback]].
Not all of these mirror all of the other "source" sites,
and some have material not available on the "source" sites.
Q: How Do I Install Linux Using FTP?|install-linux-using-ftp
A: Most distributions are too large and complex to
make FTP installation practical. Installing a basic Linux system that doesn't
have a GUI or major applications is possible with FTP, however. The main
non-commercial distribution in use is Debian GNU/Linux, and this answer
describes an installation of a basic Debian system, to which you can add
other Linux applications and commercial software as necessary.
This answer describes installation on IBM-compatible machines with an Intel
x86 or Pentium processor. You will need a machine with at least a 80386
processor, 8 Mb of memory, and about 100 Mb of disk space. More memory and a
larger disk is necessary however, for practical everyday use.
For other hardware, substitute "-arm", "-ppc", "-m68k", or other
abbreviation in directory names for "-i386".
For detailed and hardware-specific information refer to:
[[http://www.debian.org/releases/stable/]].
*Connect to
[[http://ftp.debian.org/dists/stable/main/disks-i386/current/]].
If you use anonymous FTP, connect to
[[ftp://ftp.debian.org/debian/dists/stable/main/disks-i386/current/]].
*Choose the [[dir:images-*/]] subdirectory that matches the type of floppy drive
installed on your machine, if unsure try [[dir:images-1.44/]]. Retrieve the
[[file:rescue.bin]], [[file:root.bin]], and [[file:driver-*.bin]] disk images.
Once you have installed those floppy images, the rest of the system can be retrieved
from a Debian mirror site, or installed from CD. If you have a Linux
machine, you can use dd to write the images to the diskettes. If you
are creating the installation diskettes on a MS-DOS machine, also
download the <command>RAWRITE.EXE</command> MS-DOS utility, which will copy the raw binary
images to floppy disks. Also download the [[file:install.en.txt]] document, which
contains the detailed installation instructions.
*Create the installation disk set on floppies using either <command>dd</command> under
Linux (e.g.: <literal>dd if=resc1440.bin of=/dev/fd0</literal>), or the
[[RAWRITE.EXE]] utility under MS-DOS. Be sure to label each
installation diskette.
*Insert the rescue diskette into the floppy drive and reboot the computer. If all goes well, the
Linux kernel will boot, and you will be able start the installation program
by pressing <keycap>Enter</keycap> at the <literal>boot:</literal> prompt.
*Follow the on-screen instructions for
partitioning the hard disk, installing device drivers, the basic system
software, and the Linux kernel. If the machine is connected to a local
network, enter the network information when the system asks for it.
*To install additional software over the
Internet, be sure that you have installed the <literal>ppp</literal> module
during the installation process, and run (as root) the
[[/usr/sbin/pppconfig]] utility. You will need to provide
your user name with your ISP, your password, the ISP's dial-up phone number,
the address(es) of the ISP's Domain Name Service, and the serial port that
your modem is connected to, [[/dev/ttyS0]] [[/dev/ttyS3]]. Be sure also
to specify the <literal>defaultroute</literal> option to the PPP system, so
the computer knows to use the PPP connection for remote Internet addresses.
*You may have to perform additional
configuration on the PPP scripts in the [[/etc/ppp]]
subdirectory, and in particular, the ISP-specific script in the
[[/etc/ppp/peers]] subdirectory. There are basic
instructions in each script. For detailed information, refer to the
Debian/GNU Linux installation instructions that you downloaded, the pppd
manual page (type <literal>man pppd</literal>), and the <citetitle>PPP
HOWTO</citetitle> from the Linux Documentation project,
[[http://tldp.org/]].
*Once you have a PPP connection established with your ISP (it
will be displayed in the output of ifconfig), use the dselect program to
specify which additional software you want to install. Use the
<command>apt</command> <literal>[A]ccess</literal> option to retrieve
packages via anonymous FTP, and make sure to use the
<literal>[U]pdate</literal> option to retrieve a current list of packages
from the FTP archive.
/*
Q: How Can I Get Linux Without FTP Access?|i-dont-have-ftp-access
A: The easiest thing is probably to find a friend with FTP access. If there is a Linux user's group near you, they may be able to help.
If you have a reasonably good email
connection, you could try the FTP-by-mail servers at
[[mailto:ftpmail@ftp.sunet.se]], or
[[mailto:ftpmail@ftp.uni-stuttgart.de]].
Linux is also available via traditional mail on CD-ROM. The file
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/Installation-HOWTO]], and the file
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/Distribution-HOWTO]] contain information on these distributions.
Q: How Do I Install Linux?|how-to-install
A: Once you obtain a distribution, it will contain instructions on installation.
Each distribution has its own installation program.
A: There is a very thorough installation guide on line at
[[http://heather.cs.ucdavis.edu/~matloff/linux.html]]
A: Some distributions (e.g., Debian GNU/Linux) can be installed via anonymous
FTP from various Linux archive sites, but unless you have cable, DSL,
or some other broadband Internet access, the size of the distribution makes this impractical.
See [[link:get-linux-material-by-ftp]].
Postings on the Usenet News groups, including the FAQ, are archived on
[[http://groups.google.com/]]. Search for
[[news:comp.os.linux]],
[[news:alt.uu.comp.os.linux]] and their subgroups, or whatever is appropriate, to
retrieve articles from the Linux News groups. See [[link:what-newsgroups]].
=Booting the OS|booting=
Q: Can Linux Boot from MS-DOS?|boot-linux-from-ms-dos
A: If LILO doesn't work, and if the machine has MS-DOS or
Microsoft Windows, you may be left with a computer that won't boot. This can
also happen on an upgrade to your Linux distribution. Re-installing LILO is
the last thing that the installation does.
It is vitally important when installing or upgrading Linux on a dual boot
machine, to have a MS-DOS or Windows rescue disk nearby so you can
<literal>FDISK -MBR</literal>. Then you can go about using [[LOADLIN.EXE]]
instead of LILO.
This [[config.sys]] file is one possible way to
invoke [[LOADLIN.EXE]] and boot MS-DOS or Linux.
<screen> [menu] menuitem=DOS, Dos Boot menuitem=LINUX, Linux Boot
[LINUX] shell=c: edhatloadlin.exe c: edhatautobootvmlinuz vga=5 root=/dev
[DOS] STACKS = 0,0 rem all the other DOS drivers get loaded here.
</screen>
This creates a menu where you can directly jump to
[[LOADLIN.EXE]] before all of the MS-DOS drivers get loaded.
The paths and options are peculiar to one machine and should
be intuitively obvious to the most casual observer. See the
[[LOADLIN.EXE]] docs for options. They are the same as LILO,
and options are just passed to the kernel, anyhow.
[Jim Harvey]
Q: How Can Linux Boot from OS/2's Boot Manager?|boot-linux-from-os2s-boot
A: #Create a partition using OS/2's [[FDISK.EXE]] (Not Linux's <command>fdisk</command>).
#Format the partition under OS/2, either with FAT or HPFS.
This is so that OS/2 knows about the partition being formatted.
(This step is not necessary with <application>OS/2 Warp 3.0</application>.)
#Add the partition to the Boot Manager.
#Boot Linux, and create a file system on
the partition using <command>mkfs -t ext2</command> or
<command>mke2fs</command>. At this point you may, if you like, use Linux's
<command>fdisk</command> to change the code of the new partition to type 83
(Linux Native)this may help some automated installation scripts find the
right partition to use.
#Install Linux on the partition.
#Install LILO on the Linux partition NOT on the master boot record of the hard drive.
This installs LILO as a second-stage boot loader on the Linux partition itself,
to start up the kernel specified in the LILO configuration file.
To do this, you should put
<screen> boot = /dev/hda2 </screen>
(where [[/dev/hda2]] is the partition you want to
boot from) in your [[/etc/lilo/config]] or
[[/etc/lilo.config]] file.
#Make sure that it is the Boot Manager partition that is
marked active, so that you can use Boot Manager to choose what to boot.
/#
There is a set of HOWTO's on the subject of multi-boot systems at the LDP Home Page,
[[http://tldp.org]].
Q: How Do I Set the Boot-Time Configuration?|boot-time-parameters
A: You can configure Linux at the
<literal>lilo:</literal> prompt either by typing the kernel arguments at the
<literal>BOOT lilo:</literal> prompt, or by adding an
<literal>append=</literal> directive to the
[[/etc/lilo.conf]] file; for example,
at the LILO prompt (example only):
<screen>BOOT lilo: parport=0x3bc,7
parport=0x3bc,none serial=0x3f8,4 serial=0x2f8,3 </screen>
Example statement for [[/etc/lilo.conf]]:
<programlisting>
append="parport=0x3bc,none serial=0x3f8,4 serial=0x2f8,3"
</programlisting>
If you modify the [[/etc/lilo.conf]] file, be
sure to run the <command>lilo</command> command to install the new
configuration.
Configuration notes for specific hardware
devices are in the documentation of the kernel source distribution,
[[/usr/src/linux/Documentation]] in most distributions.
Refer to the <command>lilo</command> and
[[/etc/lilo.conf]] manual pages, as well as the LDP
<citetitle>BootPrompt-HowTo</citetitle>,
see [[link:howtos-and-other-documentation]],
and the documentation in [[/usr/doc/lilo]].
Q: How Do I Get LILO to Boot the Kernel Image?|lilo-boot-kernel-image
A: From kernel versions 1.1.80 on, the compressed kernel image, which is what LILO needs to find,
is in [[arch/i386/boot/zImage]], or [[arch/i386/boot/bzImage]] when it is
built, and is normally
stored in the [[/boot/]] directory. The [[/etc/lilo.conf]] file should refer to the
[[vmlinuz]] symbolic link, not the actual kernel image.
This was changed to make it easier to build kernel versions
for several different processors from one source tree.
Q: Can I Remove LILO So the System Boots DOS Again?|remove-lilo-so-my-system-boots
A: The <command>lilo</command> program (not the complete
<application>LILO</application> package), uses the command line option
<command>-u</command> to uninstall the <application>LILO</application> boot
loader. You have to supply the device name of the device you installed
<application>LILO</application> on, for example:
<screen> lilo -u /dev/hda</screen>
This rewrites the original, pre-<application>LILO</application> master boot record back to the first hard
drive, from the boot record saved in [[/boot/boot.0300]]. If
you installed <application>LILO</application> to a partition as a secondary
boot loader, for example, [[/dev/hda1]],
<command>lilo</command> re-installs the original boot sector from the save
file [[/boot/boot.0301]]. Refer to the
<command>lilo</command> manual page for details. Thanks to Villy Kruse for
reminding me to update this answer.
If you have an earlier version of <application>LILO</application>, you will have to use the DOS
(MS-DOS 5.0 or later, or OS/2) <literal>FDISK /MBR</literal> (which is not
documented). This will overwrite the lilo boot loader with a standard <application>MS-DOS</application>
Master Boot Record. If you have <application>DR-DOS 6.0</application>, go
into [[FDISK.EXE]] in the normal way and then select the
<literal>Re-write Master Boot Record</literal> option.
If you create a boot floppy during the Windows installation process, make sure that
it contains the programs <application>FDISK.EXE</application>,
<application>FORMAT.COM</application>, and
<application>SYS.COM</application>, and use that to re-install MS-DOS on the
hard disk.
If you don't have MS-DOS or DR-DOS, you need to
have the boot sector that LILO saved when you first installed it. You did
keep that file, didn't you? It's probably called
[[boot.0301]] or some such. Type:
<screen> dd if=boot.0301 of=/dev/hda bs=445 count=1</screen>
(or [[/dev/sda]] if you're using a SCSI disk). This may also
wipe out your partition table, so beware! If you're desperate, you could use
<screen> dd if=/dev/zero of=/dev/hda bs=512 count=1</screen>
This will erase your partition table and boot sector
completely: you can then reformat the disk using your favorite software. But
this will render the contents of your disk inaccessible you'll lose it all
unless you're an expert.
Note that the <application>DOS</application> MBR boots whichever (single!) partition is
flagged as "active." You may need to use <command>fdisk</command> to set
and clear the active flags on partitions appropriately.
Q: Why Does the System Check the Ext2fs Partitions Each Reboot?|partitions-checked-each-reboot
A: Refer to [[link:ext2-fs-warning-mounting]].
Q: How Do I Make Sure the System Boots after Re-Installing the Operating System?|make-sure-it-boots
A: This should work whether you're re-installing Linux or some other, commercial, operating system:
*Insert a blank, formatted floppy in drive A:
*Save a copy of the boot hard drive's Master Boot Record to the floppy, by executing the command:
<screen> #dd if=/dev/hda of=/dev/fd0 count=1</screen>
<literal>dd</literal> is a standard program on Linux systems. A MS-Windows
compatible version is available from
[[ftp://ftp.gnu.org/]], as well as many MS software archives.
*Test that the floppy boots the system by rebooting with the floppy in the A: drive.
*Then you should be able to install the
other operating system (on a different hard drive and/or partition, if you
don't want to uninstall Linux).
*After installation, boot Linux again from the floppy, and re-install the MBR with
the command: [[/sbin/lilo]].
/*
[Jacques Guy]
Q: How To Make a Rescue Floppy|make-rescue-floppy
A: Make a file system on it with bin, etc, lib and dev
directorieseverything you need. Install a kernel on it and arrange to have
LILO boot it from the floppy (see the LILO documentation, in
[[lilo.u.*.ps]]).
If you build the kernel (or
tell LILO to tell the kernel) to have a RAM disk the same size as the floppy
the RAM disk will be loaded at boot time and mounted as root in place of the
floppy.
See the <citetitle>Bootdisk HOWTO</citetitle>.
=Application Software Management|app-management=
Q: How To Determine What Packages Are Installed on a System|determine-packages-installed
A: For distributions that use RPM format packages, use the command:
<screen> $ rpm -qa </screen>
You need to be logged in as root.
You can save the output to a text file for future reference, a command like:
<screen> $ rpm -qa >installed-packages </screen>
A: For Debian systems, the equivalent command is:
<screen>$ dpkg -l </screen>
A: For Slackware and Slackware based distributions, look in the directory
[[dir:/var/log/packages]].
[Steven J. Hathaway]
There is one file that describes the contents of each *.tgz package
installed on your system.
Q: How Do I Find a Particular Application?|ported-compiled-written-xxx
A: Look first in the Linux Software Map. It's at:
[[ftp://metalab.unc.edu/pub/Linux/docs/linux-software-map/]], and on the
other FTP sites.
A search engine is available on the World Wide Web at [[http://www.boutell.com/lsm/]].
Also check out the '''Freshmeat''' Web site: [[http://www.freshmeat.net]],
which is where many new announcements of free software first appear.
Freshmeat is basically a site index that continuously updates the notices
of new or upgraded software for Linux, and maintains indexes of the
announcements and links to their URL's.
The FTP sites ([[link:get-linux-material-by-ftp]]) often have [[ls-lR]]
or [[INDEX]] directory listings which you can search using
<command>grep</command> or a text editor.
The directory listings files can be very large, however, making them unwieldy
for quick searches.
Also look at the Linux Project's Map:
[[ftp://ftp.ix.de/pub/ix/Linux/docs/Projects-Map.gz]].
There's a search engine for Linux FTP archives at: [[http://lfw.linuxhq.com]].
Searching for "Linux" on the World Wide Web provides copious references.
([[link:world-wide-web-for-linux-stuff]])
If you don't find anything, you could download the sources to the program
yourself and compile them. See ([[link:port-xxx-to-linux]]).
If it's a large package that may require some porting, post a message to
[[news:comp.os.linux.development.apps]].
The popularity of Linux makes this an extremely unlikely occurrence.
The great majority of software available on other Unix-type
systems has already been ported to Linux.
If you compile a large-ish program, please upload it to one or more of the FTP sites,
and post a message to [[news:comp.os.linux.announce]]
(submit your posting to [[mailto:linux-announce@news.ornl.gov]].
If you're looking for an application program, the chances are that someone has
already written a free version. The [[news:comp.sources.wanted]]
FAQ has instructions for finding the source code.
Q: What Software does Linux Support?|what-software-does-linux-support
A: Linux runs all of the standard open source utilities, like GCC, (X)Emacs, the X
Window System, all the standard Unix utilities, TCP/IP (including SLIP and
PPP), and all of the hundreds of programs that people have compiled or ported
to it.
There is a DOS emulator, called DOSEMU, that lets Linux run programs written for DOS.
The latest stable release is 0.98.3. The FTP archives are at [[ftp://ftp.dosemu.org/dosemu]].
The Web site is [[http://www.dosemu.org]].
The emulator can run DOS itself and some (but not all) DOS applications.
Be sure to look at the [[README]] file to determine which version you should get.
Also, see the <citetitle>DOSEMU-HOWTO</citetitle> (slightly dated at this point
it doesn't cover the most recent version of the program), at
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO]].
Work has been progressing on WINE, an emulator for Microsoft Windows binaries.
See [[link:microsoft-windows-programs-underlinux]].
Intel Binary Compatibility Standard (iBCS2) emulator code for SVR4 ELF and
SVR3.2 COFF binaries can be included in the kernel as a compile-time option.
There is information at [[ftp://tsx-11.mit.edu/pub/linux/BETA/ibcs2/README]].
For more information see the [[ldp:INFO-SHEET]].
Some companies have commercial software available. They often announce their
availability on [[news:comp.os.linux.announce]] try searching
the archives. See [[link:are-the-newsgroups-archived-anywhere]].
Q: Can Linux Use True Type Fonts?|true-type-fonts-with-linux
A: Yes. There are a number of True Type font
servers for the X Window System. One of them is <command>xfsft</command>. Its
home page is [[http://www.dcs.ed.ac.uk/home/jec/programs/xfsft/]].
There are also instructions for configuration.
A: Another True Type font server is <command>xfstt</command>
A: People have reported success with other True Type font servers. There are links from the
<command>xfsft</command> Home Page to them as well.
A: You can also compile True Type Font support into your X server directly. Again, refer
to the <command>xfsft</command> Home Page for details.
A: Debian users should consult the [[ldp:TT-Debian-HOWTO]].
Q: Can Linux Run Microsoft Windows Programs?|microsoft-windows-programs-underlinux
A: If you need to run MS Windows programs, the
safest bet is to dual-boot Windows and Linux.
LILO, the Linux boot loader, can boot one of
several operating systems from a menu. Booting Windows is obviously the most
reliable way to run all your Windows programs.
See the LILO documentation for
details on dual booting. Also, [[LOADLIN.EXE]] (a DOS program
to load a Linux, or other OS, kernel is one way to make Linux co-exist with
DOS. [[file:LOADLIN.EXE]] is particularly handy when you want to
install Linux on a 3rd or 4th drive on a system (or when you're adding a SCSI
drive to a system with an existing IDE).
In these cases, it is
common for LILO's boot loader to be unable to find or load the kernel on the
"other" drive. So you just create a [[file:C:LINUX]] directory
(or whatever), put [[file:LOADLIN.EXE]] in it with a copy of your
kernel, and use that.
[[file:LOADLIN.EXE]] is a VCPI compliant program.
Win95 will want to "shutdown into DOS mode," to run
it (as it would with certain other DOS protected-mode programs).
Earlier versions of [[file:LOADLIN.EXE]] sometimes
required a package called [[file:REALBIOS.COM]], which required a
boot procedure on an (almost) blank floppy to map the interrupt vectors
(prior to the loading of any software drivers). (Current versions don't seem
to ship with it, and don't seem to need it).
[Jim Dennis]
A: WINE (WINE Is Not an Emulator), is a reimplementation of Windows APIs for Linux
and Unix.
WINE is a great project with huge potential, but it is still not ready for general
distribution. The WINE team is still working toward a 1.0 release.
However, it is already capable of running many Windows programs.
If you want to contribute to its development, look for the status reports in the
[[news:comp.emulators.ms-windows.wine]] newsgroup.
There is also a FAQ, compiled by P. David Gardner, at
[[ftp://metalab.unc.edu/pub/Linux/docs/faqs/Wine-FAQ/]].
A: A proprietary program called <literal>VMWare</literal> is also available
to let you run Windows under a Linux "host" operating system.
See the company's website at [[http://www.vmware.com]].
A: Another package that will help is Win4Lin, a proprietary package.
Win4Lin also allows you to run many Windows programs under *NIX.
Here is how one user reports on Win4Lin:
<blockquote><attribution>Josef Lowder</attribution>
<para>
I just finished installing it on a new installation of Mandrake 8.1 and I
have found it to be very satisfactory. It only cost $49 (received a special
offer after registering at their website for information). I installed it
in just a very few minutes, and it now allows me to run all of the Windows
applications programs I have been used to using for a long time (Pagemaker,
Lview, Paint Shop Pro, Explorer etc.) in a window on one of my Linux KDE
desktop screens ... concurrently with all of my Linux tools.
</para>
</blockquote>
Q: How Do I Install GNU Software?|install-gnu-software
A: On a correctly configured system, installing a GNU software package requires four steps:
#With the [[source.tar.gz]] archive in the
[[/usr/src/]] directory, or wherever you maintain your
source files, untar and decompress the package with the command:
<screen> tar zxvf package-name.tar.gz </screen>
#Run the <command>./configure</command> script in the
untarred source archive's top-level directory with whatever command line
arguments you need. The options that configure recognizes are usually
contained in a file called [[INSTALL]] or [[README]].
#Run <command>make</command>. This will build the source code into an executable
program (or programs) and may take a few minutes or a few hours, depending on
the speed of the computer and the size of the package.
#Run <command>make install</command>. This will install the
compiled binaries, configuration files, and any libraries in the appropriate
directories.
/#
Q: Where Can I Get Java?|where-do-i-get-java
A: The Sun Microsystems Java runtime environments and
developer's kits are at [[http://java.sun.com]]
You can also get the source code, which is licensed by Sun Microsystems.
A: The home page of IBM's Jikes Java compiler is
[[http://www10.software.ibm.com/developerworks/opensource/jikes]].
A: There is a version of Sun's HotJava browser for Linux at: [[http://www.java.sun.com/products/hotjava/]].
A: Kaffee, a free Java clone, is available from: [[http://www.kaffe.org]].
A: There is a resource page of free and commercial Java
packages at: [[http://www.blackdown.org/java-linux.html]].
A: Netscape <application>Communicator</application> comes with its own
version of the <application>Java Runtime Environment</application>, so if you
need Java only to view Web graphics, you may already have the runtime version
of the Java Virtual Machine and libraries that you need installed on your
system. You can download Communicator from [[http://www.netscape.com]].
Q: Where Can I Find Kermit for Linux?|kermit-for-linux
A: Kermit is distributed under a non-GPL copyright that
makes its terms of distribution somewhat different. The sources and some
binaries are available on [[ftp://kermit.columbia.edu]].
The WWW Home Page of the Columbia University Kermit project is
[[http://www.columbia.edu/kermit/]].
Q: Is There an ICQ Program That Runs under Linux?|icq-program-under-linux
A: Several ICQ clients are available on metalab.unc.edu. Refer to
[[link:get-linux-material-by-ftp]]).
ICQ itself does not have a Linux client, but there is a Java client at
[[http://www.mirabilis.com/download/]].
Q; Where Can I Find <command>lint</command> for Linux?|lint-for-linux
A: Roughly equivalent functionality is built into GCC. Use the <literal>-Wall</literal> option to
turn on most of the useful extra warnings. See the GCC manual for more
details (type <keycombo><keycap>F1</keycap> <keycap>i</keycap></keycombo> in
Emacs and select the entry for GCC).
There is a freely available program called <command>lclint</command> that does much the same
thing as traditional <command>lint</command>.
The announcement and source code are available at
[[ftp://ftp.sds.lcs.mit.edu/pub/lclint]];
on the World Wide Web, look at [[http://lclint.cs.virginia.edu]].
=Directory And File Management|file-management=
Q: How Do I Undelete Files?|undelete-files
A: In general, this is very hard to do on unices because of their
multitasking nature. Undelete functionality for the <citetitle>ext2fs</citetitle>
file system is being worked on, but don't hold your breath.
There are a number of packages available which
instead provide new commands for deleting and copying which move deleted
files into a "wastebasket" directory. The files can be recovered until
cleaned out automatically by background processing.
The Midnight Commander file manager provides an undelete facility that uses Ext2
file system library functions and an undelete directory for each file system.
Commercial distribution packages of MC may or may not have this feature
enabled, so be sure to look in the source code distribution for instructions
on how to enable the undelete feature.
Alternatively, you can
search the raw disk device which holds the file system in question. This is
hard work, and you will need to be logged in as root to do this. But it can
be done. Run <command>grep</command> on the raw device; e.g.:
<screen> grep -b 'bookmarks' /dev/hda</screen>
If the data has not been overwritten, you should be able to recover it with a text editor.
[Dave Cinege, Daniel Novotny]
Q: How Do I Make Backups?|how-do-i-make-backups
A: You can back up a directory hierarchy or complete
file system to any media using GNU <command>tar</command> or <command>cpio</command>,
the standard *nix tools for this purpose. <command>tar</command> seems to be the more
commonly used program currently, and includes command line options to make compressed, incremental, and
multi-volume backups. Complete information is contained in the documentation,
which is in GNU Texinfo format.
A: The free program, <application>Amanda</application>, receives a lot of mentions on Usenet. Its home page is [[http://www.amanda.org]].
A: Several commercial backup utilities also exist. They are often included in commercial
distributions.
Q:Is There a Defragmenter for Ext2fs?|defragmenter-for-ext2fs-etc]]
A: Yes. There is <application>defrag</application>, a Linux file system defragmenter
for <citetitle>ext2</citetitle>, <citetitle>Minix</citetitle>,
and old-style <citetitle>ext</citetitle> file systems. It is available at
[[ftp://metalab.unc.edu/pub/Linux/system/filesystems/defrag-0.70.tar.gz]].
Users of the <citetitle>ext2</citetitle>
file system can probably do without <application>defrag</application>,
because <citetitle>ext2</citetitle> contains extra code to keep fragmentation
reduced even in very full file systems.
=Connecting To A Network|networking=
Q: How I Configure Dial-up PPP?|get-dial-up-ppp-work
A: This information is mainly for people who do
not have a wrapper utility like <command>kppp</command> or
<command>pppconfig</command>, or are not able to get those utilities to work
correctly. If you need to manually configure PPP to dial in to your ISP, you
will need the following information:
*The port that your modem is connected to: [[/dev/ttyS0]]-[[/dev/ttyS3]], which
correspond to COM1-COM4 under MS-DOS.
*The phone number of your ISP's data connection.
*The user name and password that your ISP gave you.
*The IP addresses of the primary and possibly secondary Domain Name Service that
you will use when dialing in to the ISP. This assumes that you will not be
using a DNS that you installed on your system.
When you have all of this information, make sure that the programs <command>pppd</command> and
<command>chat</command>, at the very minimum, are installed correctly. In
most current distributions, they are installed in the
[[/usr/sbin/]] directory, and you will need to be logged in
as root to use them. In addition, the following programs are also useful for
configuring network connections, determining network status, and diagnosing
problems: [[/sbin/ifconfig]], [[/sbin/route]], [[/bin/ping]],
[[/usr/sbin/traceroute]].
These are the basic steps that you need to follow to configure PPP. You must be logged in as
root.
*Make sure that the serial port and modem are operating correctly. Using a program like
<command>minicomm</command> or <command>kermit</command>, you should be able
to send <literal>AT</literal> commands to the modem and receive the
<literal>OK</literal> string in response from the modem.
*Enter the primary and possibly secondary Domain Name Server
IP addresses in the [[/etc/resolv.conf]] file, using dotted
quad notation, with the <literal>nameserver</literal> label. For example:
<screen> order hosts,bind
nameserver 196.182.101.103
nameserver 196.182.101.104 </screen>
The nameserver addresses in the example above are examples only.
They don't correspond to actual network hosts.
The first line, <literal>order hosts,bind</literal>,
tells your networking software, when it resolves network domain addresses, to
first look in the [[/etc/hosts file]], and then use the bind
service; i.e., the DNS servers, which are specified on the lines that begin
with nameserver.
*Locate the chat script that PPP will use to dial the modem and connect to your ISP.
In many systems, this is either in the [[/etc/chatscripts]] or
[[/etc/ppp]] directory, and will be called [[provider]] or something similar. You can store a
<literal>chat</literal> script anywhere, provided that you tell
<command>pppd</command> to use it rather than the default script. Refer to
the <command>chat</command> and <command>pppd</command> manual pages, and the
information below, for details. Here is a sample <literal>chat</literal>
script:
<screen>
ABORT BUSY
ABORT "NO CARRIER"
ABORT VOICE
ABORT "NO DIALTONE"
"" ATDT<your_isp's_phone_number>
ogin <your_user_name>
word <your_password>
</screen>
This is a <command>chat</command> program for a simple, script based login. The
<command>chat</command> program uses the pair of strings on each line as a
match/response pair. When it starts, it sends the string
"ATDT'''your_isp's_phone_number'''," where you have
substituted the actual phone number of course. It then waits for the string
<literal>ogin</literal> (a substring of the word <literal>login</literal>)
and sends your user name. It then waits for <literal>word</literal> (a
substring of <literal>password</literal>) and sends your password. If your
ISP uses a different login and password prompts, and any additional prompts,
you will need to edit the script accordingly. Again, refer to the
<command>chat</command> manual page for details.
If your ISP uses PAP or CHAP authentication, you will need to edit the
[[pap-secrets]] or [[chap-secrets]] files
in [[/etc/ppp]] directory as well. Refer to the manual pages
for these files, as well as the instruction in the files themselves.
*The configuration of <command>pppd</command>, the program that maintains the actual connection, is
usually contained in two or three separate files. The first is usually
[[/etc/ppp/options]], which contains options that all of
your system's PPP connections will use. (Yes, you can have more than one; as
many as your computer has serial ports, generally.)
Here is a sample [[/etc/ppp/options]] file:
<screen> #/etc/ppp/options
asyncmap
0
auth
crtscts
lock
noipx
# ---<End of File>--- </screen>
The options may be given on one
line or each on a separate line. Many options files are much longer, and come
with a description of each option. Here, the options mean, in order, don't
remap any characters between the PPP client and server; always use password,
PAP, or CHAP authentication when making a connection; use the modem's
hardware handshake lines for flow control; lock the serial port when in use
so no other programs can access it; and do not use the IPX network protocol.
*For connection set-up on each individual
serial port or PPP host, there will either be an
[[/etc/ppp/options.ttyS1]], for example, options file for
[[/etc/ttyS1]], or a file for your ISP in the
[[/etc/ppp/peers]] directory. The default is often called
[[/etc/ppp/peers/provider]]. Here is a sample of the default
[[provider]] file:
<screen> noauth
connect "/usr/sbin/chat -v -f /etc/chatscripts/provider"
defaultroute
/dev/ttyS1
38400
persist
</screen>
There might be an explanation of these
and other options in the [[/etc/ppp/peers/provider]] file
itself. You can also refer to the <command>pppd</command> manual page for
details. Briefly, they mean: do not use PAP authentication for this
connection; use the <command>chat</command> program and the
[[/etc/chatscripts/provider]] script, which is described
above, to dial the phone and log in; set the network default route to the PPP
connection (so when your network software needs to resolve an network address
that is not on your local machine(s), it will use the PPP connection to the
Internet); use [[/dev/ttyS1]] as the serial port for the
connection; set the modem speed to 38400; and keep the
<command>pppd</command> daemon running even if the connection fails.
/*
That is all of the configuration you
need. To actually start and stop PPP, there are often
[[/usr/bin/pon]] and [[/usr/bin/poff]]
scripts (in Debian), or something similar, and they are usually very simple,
and only contain the command:
<screen> $ /usr/sbin/pppd call ${1:-provider} </screen>
This will start <command>pppd</command> and use the <literal>call</literal> option to call
the server that you type on the command line, or the provider given in the
[[/etc/ppp/peers/provider]] file if you do not specify a
remote server. After making the call and logging in (about 30 seconds), you
should be able to use the [[/sbin/ifconfig]] program to
determine that the connection really did establish a PPP interface (the first
will be [[ppp0]], the second will be
[[ppp1]], etc., depending on how many simultaneous PPP
connections you have. If something goes wrong, you can look at the
[[/var/log/ppp.log]] file to determine what happened. You
can also view the log as the connection is being made, by "tailing" it in
another window; that is, viewing it as pppd logs the connection's status
information. To do this, use the command (again, as root):
<screen> $ tail -f /var/log/ppp.log </screen>
On some systems the PPP output is directed to [[/var/log/messages]],
in which case your system may not have a dedicated PPP log file.
You should be also able to <command>ping</command> one of your ISP's domain names (e.g.,
<literal>mail.isp.com</literal>) and receive a response.
These are the most basic steps for configuring a PPP connection. You will also need
to take into account what other network connections may be present (for
example, if there's an Ethernet connection that has already been assigned the
default route), as well as various security measures at your ISP's end. If
you're having trouble making the dial-up connection, usually the best way to
determine what may be going wrong is to use Seyon, minicomm, kermit, or some
other program to dial and log in manually to the ISP, and determine just
exactly what you have to do to log in, then duplicate that in the PPP
scripts.
Most Linux documentation also has additional
instructions for configuring PPP connections.
Refer to [[link:get-linux-material-by-ftp]] and
[[link:howtos-and-other-documentation]].
Q: How Do I Use Linux with a Cable Modem?|linux-cable-modem
A: The www.CablemodemInfo.com and xDSL Web page at
[[http://www.cablemodeminfo.com]] has a section devoted to Linux.
See also the [[ldp:Cable-Modem-HOWTO]] at the LDP.
Q: Where Is Information about NFS Compatibility?|information-about-nfs-compatibility
A: See the [[NFS-HOWTO]] for up to date information.
A: This information is partly taken from Nicolai Langfeldt's excellent NFS HOWTO,
and is current as of 10/1/1999:
Most version 2.2.x kernels need a set of patches
to install the <command>knfsd</command> subsystem, maintained by H.J. Lu, to
communicate efficiently (if at all) with Sparc, IBM RS, and Alpha machines,
and probably others. This package is actually a collection of patches to the
kernel sources. Better support for non-Intel architectures is included in the
2.4 kernels.
There is also a user-space server. Although it lacks remote file locking,
it is easier to install. It may be equally efficient.
In the [[Documentation/Changes]]
of recent kernel distributions, there is a list of URL's for both the
<command>knfsd</command> server and the user-space server.
In the case of older Solaris releases, the
lack of <literal>statd</literal> or <literal>lockd</literal> on a client or
server machine may cause incompatibility. On some versions of Solaris,
<literal>statd</literal> can be used to exploit features of the automounter.
Sun released a patch to correct this, but <literal> statd</literal> still
needs to be started by root on such systems. On recent Solaris systems, refer
to the information in <literal>/etc/dfs/dfstab</literal> and the
<literal>share(1M)</literal> manual page to enable volume sharing. In
addition, the <literal>rpcinfo</literal> program can tell you if
<literal>statd</literal> or <literal>lockd</literal> are available on the
local or remote machines.
The <literal>linux-kernel</literal> mailing list has on-and-off discussions of the status of the NFS subsystem,
which appears to be changing rapidly.
[Nicolai Langfeldt, Robert Kiesling, Anders Hammarquist]
Q: What Does VFS Stand For?|vfs
A: '''Virtual File System'''. It's the abstraction layer between
the user and real file systems like <citetitle>ext2</citetitle>,
<citetitle>Minix</citetitle> and <citetitle>MS-DOS</citetitle>. Among other
things, its job is to flush the read buffer when it detects a disk change on
the floppy disk drive.
<screen> VFS: Disk change detected on device 2/0 </screen>
Q: Can Linux Access SMB File Systems?|can-linux-access-smb-file-systems
A: Linux supports read/write access of
Windows for Workgroups and Windows NT SMB volumes. See the file
Documentation/filesystems/smbfs.txt of the Linux kernel source distribution,
and [[link:upgrade-recompile-kernel]].
There is also a suite
of programs called Samba which provide support for WfW networked file systems
(provided they're for TCP/IP). Information is available in the
[[README]] file at
[[metalab.unc.edu/pub/Linux/system/network/samba/]].
The SMB Web site is [[http://www.samba.org]], and there is also a Web
site at [[samba.anu.edu.au/samba/]].
=Troubleshooting|troubleshooting=
Q: What are these Nasty Messages about Inodes, Blocks, and the Like?|nasty-messages-about-inodes
A: You may have a corrupted file system, probably caused by not shutting Linux down
properly before turning off the power or resetting. You need to use a recent
shutdown program to do this for example, the one included in the util-linux
package, available on sunsite and tsx-11.
If you're lucky, the program <command>fsck</command> (or <command>e2fsck</command>
or <command>xfsck</command> as appropriate if you don't have the
automatic <command>fsck</command> front-end) will be able to repair your file system.
If you're unlucky, the file system is trashed, and you'll have to
re-initialize it with mkfs (or <command>mke2fs</command>, <command>mkxfs</command>, etc.),
and restore from a backup.
NB: don't try to check a file system that's mounted read/writethis includes
the root partition, if you don't see
<screen> VFS: mounted root
... read-only</screen>
at boot time.
Q: Why Do FTP Transfers Seem to Hang?|ppp-connection-dies-when-sending
A: FTP transfers that die suddenly are due, apparently,
to some form of overrunning buffer.
It occurs both with Linux and Microsoft servers. On Linux systems, the problem seems to occur
most commonly with the distribution's server software.
If you receive <literal>ftp: connection refused</literal> errors, then the problem
is likely due to a lack of authentication.
Refer to [[link:ftp-wont-login]].
One remedy is to be replacing the distribution FTP server with the Linux port of
the OpenBSD FTP server. The home page is:
[[http://www.eleves.ens.fr:8080/home/madore/programs/]].
To install the BSD server, follow the installation
instructions, and refer to the manual pages for [[inetd]]
and [[inetd.conf]]. (If you have the newer [[xinetd]], see below.)
Be sure to tell [[inetd]] to run the BSD daemon alone, not as a subprocess
of, for example, [[tcpd]]. Comment out the line that begins
<literal>ftp</literal> in the [[/etc/inetd.conf]] file
and replace it with a line similar to (if you install the new
[[ftpd]] in [[/usr/local/sbin/]]):
<programlisting>
# Original entry, commented out. #ftp stream tcp nowait root /usr/sbin/tcpd
/usr/sbin/in.ftpd
# Replacement entry: ftp stream tcp nowait root /usr/local/sbin/ftpd -l
</programlisting>
The replacement daemon will become effective
after rebooting or sending (as root) a <literal>SIGHUP</literal> to
<literal>inetd</literal>, e.g.:
<screen> # kill -HUP inetd</screen>
To configure [[xinetd]], create an entry in [[/etc/xinetd.d]] per the instructions in the
[[xinetd.conf]] manual page. Make sure, again, that the
command-line arguments for [[ftpd]] are correct, and that
you have installed the [[/etc/ftpusers]] and
[[/etc/pam.d/ftp]] files. Then restart [[xinetd]] with the command:
<literal>/etc/rc.d/init.d/xinetd restart</literal>. The command should report
"OK," and the restart will be noted in the system message log.
Q: Why Does Free Dump Core?|free-dumps-core
A: In Linux 1.3.57 and later, the format of [[/proc/meminfo]] was changed in a way that the
implementation of <application>free</application> doesn't understand.
Get the latest version, from metalab.unc.edu, in
[[/pub/Linux/system/Status/ps/procps-0.99.tgz]].
Q: Why Does Netscape Crash Frequently?|netscape-crashes
A: Netscape shouldn't crash, if it and the network are properly configured. Some things to check:
*Make sure that the <literal>MOZILLA_HOME</literal>
environment variable is correctly set. If you installed Netscape under
[[/usr/local/netscape/]], for example, that should be the
value of <literal>MOZILLA_HOME</literal>. Set it from the command line (e.g,
"<literal>export MOZILLA_HOME="/usr/local/netscape"</literal>" under
<command>bash</command> or add it to one your personal or system
initialization files. Refer to the manual page for your shell for details.
*If you have a brand-new version of
Netscape, try a previous version, in case the run-time libraries are slightly
incompatible. For example, if Netscape version 4.75 is installed (type
"<literal>netscape --version</literal>" at the shell prompt), try
installing version 4.7. All versions are archived at [[ftp://ftp.netscape.com/]].
*Netscape uses its own Motif and Java Runtime Environment
libraries. If a separate version of either is installed on your system,
ensure that they aren't interfering with Netscape's libraries; e.g., by
un-installing them.
*Make sure that Netscape can connect to its default name servers. The program will appear to
freeze and time out after several minutes if it can't. This indicates a
problem with the system's Internet connection; likely, the system can't
connect to other sites, either.
/*
Q: Why Won't My FTP or Telnet Server Allow Logins?|ftp-wont-login
A: This applies to server daemons that respond to
clients, but don't allow logins. On new systems that have Pluggable
Authentication Modules installed, look for a file named,
"[[ftp]]," or "[[telnet]]," in the directory [[/etc/pam/]] or [[/etc/pam.d/]].
If the corresponding authentication file doesn't exist, the instructions for
configuring FTP and Telnet authentication and other PAM configuration, should
be in [[/usr/doc/pam-&amp;version&amp;]]. Refer also to the answer for
[[link:ftp-421-error]].
If it's an FTP server on an older system, make sure that the account exists in
[[/etc/passwd]], especially <literal>anonymous</literal>.
This type of problem may also be caused a failure to resolve the host addresses properly, especially
if using Reverse Address Resolution Protocol (RARP). The simple answer to
this is to list all relevant host names and IP addresses in the
[[/etc/hosts]] files on each machine. ( Refer to the example
[[/etc/hosts]] and [[/etc/resolv.conf]]
files in [[link:sendmail-pause]].
If the network has an internal DNS, make sure that each host can resolve network
addresses using it.
If the host machine doesn't respond to FTP
or Telnet clients at all, then the server daemon is not installed correctly,
or at all. Refer to the manual pages: <literal>inetd</literal> and
<literal>inetd.conf</literal> on older systems, or <literal>xinetd</literal>
and <literal>xinetd.conf</literal>, as well as <literal>ftpd</literal>, and
<literal>telnetd</literal>.
Q: How Do I Keep Track of Bookmarks in Netscape?|track-of-bookmarks-netscape
A: This probably applies to most
other browsers, too. In the Preferences/Navigator menu, set your home page to
Netscape's [[bookmarks.html]] file, which is located in the
[[.netscape]] (with a leading period) subdirectory. For
example, if your login name is <literal>smith</literal>, set the home
page to:
<screen> file://home/smith/.netscape/bookmarks.html</screen>
Setting up your personal home page like this will
present you with a nicely formatted (albeit possibly long) page of bookmarks
when Netscape starts. And the file is automatically updated whenever you add,
delete, or visit a bookmarked site.
Q: Why Does the Computer Have the Wrong Time?|computer-has-wrong-time
A: There are two clocks in your computer. The
hardware (CMOS) clock runs even when the computer is turned off, and is used
when the system starts up and by DOS (if you use DOS). The ordinary system
time, shown and set by <command>date</command>, is maintained by the kernel
while Linux is running.
You can display the CMOS clock time,
or set either clock from the other, with [[/sbin/clock]]
(now called <command>hwclock</command> in many distributions). Refer to:
<literal>man 8 clock</literal> or <literal>man 8 hwclock</literal>.
There are various other programs that can correct either or both
clocks for system drift or transfer time across the network. Some of them may
already be installed on your system. Try looking for
<command>adjtimex</command> (corrects for drift), Network Time Protocol
clients like <command>netdate</command>, <command>getdate</command>, and
<command>xntp</command>, or NTP client-server suite like
<command>chrony</command>.
Refer to [[link:ported-compiled-written-xxx]].
Q: Why Don't Setuid Scripts Work?|setuid-scripts-dont-work
A: They aren't supposed to. This feature has been
disabled in the Linux kernel on purpose, because setuid scripts are almost
always a security hole. <application>Sudo</application> and
<application>SuidPerl</application> can provide more security than setuid
scripts or binaries, especially if execute permissions are limited to a
certain user ID or group ID.
If you want to know why setuid scripts are a security hole, read the FAQ for
[[news:comp.unix.questions]].
Q: Why Is Free Memory as Reported by <command>free</command> Shrinking?|free-memory-keeps-shrinking
A: The "<literal>free</literal>" figure printed by <command>free</command> doesn't
include memory used as a disk buffer cacheshown in the
<literal>buffers</literal> column. If you want to know how much memory is
really free add the <literal>buffers</literal> amount to
<literal>free</literal>. Newer versions of <command>free</command> print
an extra line with this info.
The disk buffer cache tends to
grow soon after starting Linux up. As you load more programs and use more
files, the contents get cached. It will stabilize after a while.
Q: Why Does the System Slow to a Crawl When Adding More Memory?|add-memory-system-slows
A: This is a common symptom of a failure to cache the additional memory.
The exact problem depends on your motherboard.
Sometimes you have to enable caching of
certain regions in your BIOS setup. Look in the CMOS setup and see if there
is an option to cache the new memory area which is currently switched off.
This is apparently most common on a '486.
Sometimes the RAM has to be in certain sockets to be cached.
Sometimes you have to set jumpers to enable caching.
Some motherboards don't cache all of the RAM if you have more RAM per amount of cache than the
hardware expects. Usually a full 256K cache will solve this problem.
If in doubt, check the manual. If you still can't fix it because the
documentation is inadequate, you might like to post a message to
[[news:comp.os.linux.hardware]] giving all of the details make,
model number, date code, etc., so other Linux users can avoid it.
Q: Why Won't Some Programs (e.g., <command>xdm</command>) Allow Logins?|some-programs-wont-log-in
A: You are probably using non-shadow password programs and are using shadow passwords.
If so, you have to get or compile a shadow password version of
the programs in question. The shadow password suite can be found at
[[ftp://tsx-11.mit.edu/pub/linux/sources/usr.bin/shadow/]]. This is the source code.
The binaries are probably in [[linux/binaries/usr.bin/]].
Q: Why Do Some Programs Allow Logins with No Password?|log-in-with-no-password
A: You probably have the same problem as in [[link:some-programs-wont-log-in]],
with an added wrinkle.
If you are using shadow passwords, you should put a letter
<literal>x</literal> or an asterisk in the password field of
[[/etc/passwd]] for each account, so that if a program
doesn't know about the shadow passwords it won't think it's a passwordless
account and let anyone in.
Q: Why Does the Machine Run Very Slowly with GCC / X / ...?|machine-runs-very-slowly-when
A: You may have too little real memory. If you have less RAM than all the programs you're running at
once, Linux will swap to your hard disk instead and thrash horribly. The
solution in this case is to not run so many things at once or buy more
memory. You can also reclaim some memory by compiling and using a kernel with
fewer options configured.
See [[link:upgrade-recompile-kernel]].
You can tell how much memory and swap you're using with the free command,
or by typing:
<screen> $ cat /proc/meminfo</screen>
If your kernel is configured with a RAM disk, this is probably wasted space and will cause
things to go slowly. Use LILO or rdev to tell the kernel not to allocate a
RAM disk (see the LILO documentation or type <literal>man rdev</literal>).
Q: Why Does My System Only Allow Root Logins?|can-only-log-in-as-root
A: You probably have some permission problems, or you have a file [[/etc/nologin]].
In the latter case, put <literal>rm -f /etc/nologin</literal> in your
[[/etc/rc.local]] or [[/etc/rc.d/*]] scripts.
Otherwise, check the permissions on your shell, and
any file names that appear in error messages, and also the directories that
contain these files, up to and including the root directory.
Q: Why Is the Screen Is All Full of Weird Characters Instead of Letters?|screen-is-all-full-of-weird
A: You probably sent some binary data to your screen by mistake.
Type <literal>echo 'c'</literal> to fix it.
Many Linux distributions have a command,
<command>reset</command>, that does this.
If that doesn't help, try a direct screen escape command:
<literal>echo '<keycombo><keycap>Ctrl</keycap><keycap>V</keycap></keycombo>
<keycombo><keycap>Ctrl</keycap><keycap>O</keycap></keycombo>'</literal>.
This resets the default font of a Linux console.
Remember to hold down the Control key and type the letter, instead of, for
example, <keycombo><keycap>Ctrl</keycap></keycombo>, then
<keycombo><keycap>V</keycap></keycombo>.
The sequence <keycombo><keycap>Ctrl</keycap><keycap>V</keycap></keycombo>
<keycap>Esc</keycap> <keycap>C</keycap>.
causes a full screen reset. If there's data left on the shell command line after
typing a binary file, press
<keycombo><keycap>Ctrl</keycap><keycap>C</keycap></keycombo> a few times to
restore the shell command line.
Another possible command is an alias, <literal>sane</literal>, that can work with generic terminals:
<screen> $ alias sane='echo -e " c";tput is2;
> stty sane line 1 rows $LINES columns $COLUMNS'</screen>
The alias is enclosed with open quotes (backticks), not single quotes. The line break is included
here for clarity, and is not required.
Make sure that <literal>$LINES</literal> and <literal>$COLUMNS</literal> are defined in the
environment with a command similar to this in [[~/.cshrc]]
or [[~/.bashrc]],
<screen> $ LINES=25; export $LINES; $COLUMNS=80; export $COLUMNS</screen>
using the correct numbers of <literal>$LINES</literal> and <literal>$COLUMNS</literal>
for the terminal.
Finally, the output of <command>stty -g</command> can be used to create a shell script
that will reset the terminal:
#Save the output of <command>stty -g</command> to a file. In this example, the file is named [[termset]]:
<screen> $ stty -g >termset </screen>
The output of <command>stty -g</command> (the contents of [[termset]])
will look something like:
<screen> 500:5:bd:8a3b:3:1c:7f:15:4:0:1:0:11:13:1a:0:12:f:17:16:0:0:73</screen>
#Edit [[termset]] to become a shell script; adding an
interpreter and <command>stty</command> command:
<screen> #!/bin/bash stty 500:5:bd:8a3b:3:1c:7f:15:4:0:1:0:11:13:1a:0:12:f:17:16:0:0:73</screen>
#Add executable permissions to <command>termset</command> and use as a shell script:
<screen> $ chmod +x termset $ ./termset</screen>
/#
[Floyd L. Davidson, Bernhard Gabler]
Q: If I Screwed Up the System and Can't Log In, How Can I Fix It?|screwed-up-system-and-cant-log-in
A: You did create an emergency floppy (or floppies), right?
Reboot from an emergency floppy or floppy pair.
For example, the Slackware boot and root disk pair in the install
subdirectory of the Slackware distribution.
A: There are also two, do-it-yourself rescue disk creation packages in
[[ftp://metalab.unc.edu/pub/Linux/system/recovery/]].
These are better because they have your own kernel on them, so you don't run
the risk of missing devices and file systems.
Get to a shell prompt and mount your hard disk with something like
<screen> $ mount -t ext2 /dev/hda1 /mnt</screen>
Then your file system is available under the directory [[/mnt]] and you can fix the
problem. Remember to unmount your hard disk before rebooting
(<command>cd</command> somewhere else first, or it will say it's busy).
Q: What if I Forget the <literal>root</literal> Password?|forgot-root-password
A: <warning>Incorrectly editing any of the files in the [[/etc/]] directory can
severely screw up a system. Please keep a spare copy of any files in case you
make a mistake.</warning>
If your Linux distribution permits,
try booting into single-user mode by typing <literal>single</literal> at
the <literal>BOOT lilo:</literal> prompt. With more recent distributions, you
can boot into single-user mode when prompted by typing <literal>linux
1</literal>, <literal>linux single</literal>, or
<literal>init=/bin/bash</literal>.
If the above doesn't work for you, boot from the installation or rescue floppy,
and switch to another virtual console with
<keycombo><keycap>Alt</keycap><keycap>F1</keycap></keycombo> --
<keycombo><keycap>Alt</keycap><keycap>F8</keycap></keycombo>, and then mount
the root file system on <literal>/mnt</literal>. Then proceed with the steps
below to determine if your system has standard or shadow passwords, and how
to remove the password.
Using your favorite text editor, edit
the root entry of the [[/etc/passwd]] file to remove the
password, which is located between the first and second colons. '''Do
this only if the password field does not contain an <literal>x</literal>,
in which case see below.'''
<screen> root:Yhgew13xs:0:0: ...</screen>
Change that to:
<screen> root::0:0: ...</screen>
If the password field contains an <literal>x</literal>, then you must remove the password from
the [[/etc/shadow]] file, which is in a similar format.
Refer to the manual pages: <literal>man passwd</literal>, and
<literal>man 5 shadow</literal>.
[Paul Colquhuon, Robert Kiesling, Tom Plunket]
Q: What's This Huge Security Hole in <command>rm</command>!?!?!|a-security-hole-in-rm
A: No there isn't. You are obviously new to unices and need to read a good book to find out how things work. Clue: the ability to delete files depends on permission to write
in that directory.
Q: Why Don't <command>lpr</command> and/or <command>lpd</command> Work?|lpr-andor-lpd-dont-work
A: First make sure that your [[/dev/lp*]] port is correctly
configured. Its IRQ (if any) and port address need to match the settings on
the printer card. You should be able to dump a file directly to the printer:
<screen> $ cat the_file >/dev/lp1</screen>
If <command>lpr</command> gives you a message like <literal>myname@host: host
not found</literal>" it may mean that the TCP/IP loopback interface,
<literal>lo</literal>, isn't working properly. Loopback support is compiled
into most distribution kernels. Check that the interface is configured with
the ifconfig command. By Internet convention, the network number is
127.0.0.0, and the local host address is 127.0.0.1. If everything is
configured correctly, you should be able to telnet to your own machine and
get a login prompt.
Make sure that [[/etc/hosts.lpd]] contains the machine's host name.
If your machine has a network-aware <command>lpd</command>, like the
one that comes with LPRng, make sure that [[/etc/lpd.perms]]
is configured correctly.
Also look at the <citetitle>Printing HOWTO</citetitle>. "Where can I get the
HOWTO's and other documentation? ".
Q: Why Are the Timestamps on Files on MS-DOS Partitions Set Incorrectly?|timestamps-on-files-are-incorrectly
A: There is a bug in the program <command>clock</command> (often found in
[[/sbin]]). It miscounts a time zone offset, confusing
seconds with minutes or something like that. Get a recent version.
Q: Why is My Root File System Read-Only?|root-file-system-read-only
A: To understand how you got into this state, see
[[link:ext2-fs-warning-mounting]].
Remount it. If [[/etc/fstab]] is correct, you can simply type:
<screen> mount -n -o remount /</screen>
If [[/etc/fstab]] is wrong, you must give the device name and possibly
the type, too: e.g.
<screen>mount -n -o remount -t ext2 /dev/hda2 /</screen>
Q: What Is [[/proc/kcore]]?|huge-proc-kcore
A: None of the files in [[/proc]] are really therethey're all, "pretend," files
made up by the kernel, to give you information about the system and don't
take up any hard disk space.
[[/proc/kcore]] is like an "alias" for the memory in your computer.
Its size is the same as the amount of RAM you have, and if you read it as a file,
the kernel does memory reads.
Q: Why Does <command>fdformat</command> Require Superuser Privileges?|fdformat-except-as-root
A: The system call to format a floppy can only be done as root, regardless of the
permissions of [[/dev/fd0*]]. If you want any user to be
able to format a floppy, try getting the <command>fdformat2</command>
program. This works around the problems by being setuid to root.
Q: Why Doesn't My PCMCIA Card Work after Upgrading the Kernel?|upgraded-kernel-pcmcia-doesnt-work
A: The PCMCIA Card Services modules, which are located in
[[/lib/modules/]]'''version'''[[/pcmcia]],
where '''version''' is the version number of the kernel, use
configuration information that is specific to that kernel image only. The
PCMCIA modules on your system will not work with a different kernel image.
You need to upgrade the PCMCIA card modules when you upgrade the kernel.
When upgrading from older kernels, make sure that you have the
most recent version of the run-time libraries, the modutils package, and so
on. Refer to the file [[Documentation/Changes]] in the
kernel source tree for details.
Important: If you use the
PCMCIA Card Services, do not enable the <literal>Network device
support/Pocket and portable adapters</literal> option of the kernel
configuration menu, as this conflicts with the modules in Card Services.
Knowing the PCMCIA module dependencies of the old kernel is
useful. You need to keep track of them. For example, if your PCMCIA card
depends on the serial port character device being installed as a module for
the old kernel, then you need to ensure that the serial module is available
for the new kernel and PCMCIA modules as well.
The procedure described here is somewhat kludgey, but it is much easier than re-calculating
module dependencies from scratch, and making sure the upgrade modules get
loaded so that both the non-PCMCIA and PCMCIA are happy. Recent kernel
releases contain a myriad of module options, too many to keep track of
easily. These steps use the existing module dependencies as much as possible,
instead of requiring you to calculate new ones.
However, this procedure does not take into account instances where module dependencies are
incompatible from one kernel version to another. In these cases, you'll need
to load the modules yourself with insmod, or adjust the module dependencies
in the [[/etc/conf.modules]] file. The
[[Documentation/modules.txt]] file in the kernel source tree
contains a good description of how to use the kernel loadable modules and the
module utilities like <command>insmod</command>, <command>modprobe</command>,
and <command>depmod</command>. [[Modules.txt]] also contains
a recommended procedure for determining which features to include in a
resident kernel, and which to build as modules.
Essentially, you need to follow these steps when you install a new kernel.
*Before building the new kernel, make a record
with the <command>lsmod</command> command of the module dependencies that
your system currently uses. For example, part of the <command>lsmod</command>
output might look like this:
<screen>
Module Pages Used by
memory_cs 2 0
ds 2 [memory_cs] 3
i82365 4 2
pcmcia_core 8 [memory_cs ds i82365] 3
sg 1 0
bsd_comp 1 0
ppp 5 [bsd_comp] 0
slhc 2 [ppp] 0
serial 8 0
psaux 1 0
lp 2 0
</screen>
This tells you for example that the [[memory_cs]] module needs the ds and
[[pcmcia_core]] modules loaded first. What it doesn't say is
that, in order to avoid recalculating the module dependencies, you may also
need to have the [[serial]], [[lp]], [[psaux]], and other standard modules available to prevent
errors when installing the pcmcia routines at boot time with
<command>insmod</command>. A glance at the [[/etc/modules]]
file will tell you what modules the system currently loads, and in what
order. Save a copy of this file for future reference, until you have
successfully installed the new kernel's modules. Also save the
<command>lsmod</command> output to a file, for example, with the command:
<command>lsmod >lsmod.old-kernel.output</command>.
*Build the new kernel, and install the boot image, either
[[zImage]] or [[bzImage]], to a floppy
diskette. To do this, change to the [[arch/i386/boot]]
directory (substitute the correct architecture directory if you don't have an
Intel machine), and, with a floppy in the diskette drive, execute the
command:
<screen> $ dd if=bzImage of=/dev/fd0 bs=512</screen>
if you built the kernel with the <command>make
bzImage</command> command, and if your floppy drive is
[[/dev/fd0]]. This results in a bootable kernel image being
written to the floppy, and allows you to try out the new kernel without
replacing the existing one that LILO boots on the hard drive.
*Boot the new kernel from the floppy to make sure that it works.
*With the system running the new kernel, compile and install a current version of the PCMCIA
Card Services package, available from metalab.unc.edu as well as other Linux
archives. Before installing the Card Services utilities, change the names of
[[/sbin/cardmgr]] and [[/sbin/cardctl]] to [[/sbin/cardmgr.old]] and
[[/sbin/cardctl.old]]. The old versions of these utilities
are not compatible with the replacement utilities that Card Services
installs. In case something goes awry with the installation, the old
utilities won't be overwritten, and you can revert to the older versions if
necessary. When configuring Card Services with the <literal>make
config</literal> command, make sure that the build scripts know where to
locate the kernel configuration, either by using information from the running
kernel, or telling the build process where the source tree of the new kernel
is. The <literal>make config</literal> step should complete without
errors. Installing the modules from the Card Services package places them in
the directory [[/lib/modules/]]'''version'''[[/pcmcia]],
where '''version''' is the version number of the new kernel.
*Reboot the system, and note which, if
any, of the PCMCIA devices work. Also make sure that the non-PCMCIA hardware
devices are working. It's likely that some or all of them won't work. Use
<command>lsmod</command> to determine which modules the kernel loaded at boot
time, and compare it with the module listing that the old kernel loaded,
which you saved from the first step of the procedure. (If you didn't save a
listing of the <command>lsmod</command> output, go back and reboot the old
kernel, and make the listing now.)
*When all modules are properly loaded, you can replace the old kernel image on the
hard drive. This will most likely be the file pointed to by the
[[/vmlinuz]] symlink. Remember to update the boot sector by
running the <command>lilo</command> command after installing the new kernel
image on the hard drive.
*Also look at the questions, How do I upgrade/recompile my kernel? and Modprobe can't
locate module, "XXX," and similar messages.
/*
=Software Development|development=
Q: How Do I Compile Programs?|how-do-i-compile-programs
A: Most Linux software is written in C and compiled
with the GNU C compiler. GCC is a part of every Linux distribution. The
latest compiler version, documentation, and patches are on
[[ftp://ftp.gnu.org/pub/gnu/]].
Programs that are written in C++ must be compiled with the GNU G++ compiler,
which is also included in Linux distributions and available from the same
place as GCC.
To build version 2.0.x kernels, you will need
GCC version 2.7.2.x, approximately. Trying to build an early Linux kernel
with a different compiler, like GCC 2.8.x, EGCS, or PGCC, may cause problems
because of GCC related code dependencies. Kernel versions 2.2, 2.4, and the 2.5 development kernels should compile correctly with more recent compilers.
Information on the EGCS compiler is at [[http://www.gnu.org/software/gcc/gcc.html]].
Note that at this time, the kernel developers are not answering bug
requests for earlier kernels, but instead are concentrating on developing
2.5.x version kernels and maintaining 2.2.x and 2.4.x version kernels.
[J.H.M. Dassen, Axel Boldt]
Q: How Do I Port '''XXX''' to Linux?|port-xxx-to-linux
A: In general, *nix programs need very little porting. Simply follow the installation instructions.
If you don't know and don't know how to find out the answers to some of the
questions asked during the installation procedure, you can guess, but this
tends to produce buggy programs. In this case, you're probably better off
asking someone else to do the port.
If you have a BSD-ish program, you should try using <command>-I/usr/include/bsd</command>
and <command>-lbsd</command> on the appropriate parts of the compilation lines.
Q: Can I Use Code or a Compiler Compiled for a 486 on a 386?|code-or-compiler-for-486-on-386
A: Yes, unless it's the kernel.
The <command>-m486</command> option to <application>GCC</application>,
which is used to compile binaries for x486
machines, merely changes certain optimizations. This makes for slightly
larger binaries that run somewhat faster on a 486. They still work fine on a
386, though, with a small performance hit.
However, from version 1.3.35 the kernel uses 486 or Pentium-specific instructions if
configured for a 486 or Pentium, thus making it unusable on a 386.
<application>GCC</application> can be configured for a 386 or 486; the
only difference is that configuring it for a 386 makes
<command>-m386</command> the default and configuring for a 486 makes
<command>-m486</command> the default. In either case, these can be overridden
on a per-compilation basis or by editing [[/usr/lib/gcc-lib/i*-linux/]]
'''n.n.n'''[[/specs]].
There is an alpha version of <application>GCC</application> that knows how to do
optimization well for the 586, but it is quite unreliable, especially at high
optimization settings. The Pentium GCC can be found on
[[ftp://tsx-11.mit.edu/pub/linux/ALPHA/pentium-gcc/]].
The ordinary 486 GCC supposedly produces better code for the
Pentium using the <command>-m386</command>, or at least slightly smaller.
Q: What Does <literal>gcc -O6</literal> Do?|what-does-gcc-o6-do
A: Currently, the same as <command>-O2</command> (<application>GCC</application> 2.5) or
<command>-O3</command> (<application>GCC</application> 2.6, 2.7). Any number
greater than that does the same thing. The [[Makefile]]s of
newer kernels use <command>-O2</command>, and you should probably do the
same.
Q: What Do I Do About Errors Trying to Compile the Kernel?|errors-when-i-try-to-compile
A: See the previous question regarding the header files.
Remember that when you apply a patch to the kernel, you must use the <literal>-p0</literal> or
<literal>-p1</literal> option: otherwise, the patch may be misapplied.
See the patch manual page for details.
<literal>ld: unrecognized option -qmagic</literal> means that you should get a newer
linker, from [[ftp://tsx-11.mit.edu/pub/linux/packages/GCC/]], in
the file [[binutils-2.8.1.0.1.bin.tar.gz]].
Q: How Do I Make a Shared Library?|make-shared-library
A: For <acronym>ELF</acronym>,
<screen> $ gcc -fPIC -c *.c
$ gcc -shared -Wl,-soname,libfoo.so.1 -o libfoo.so.1.0 *.o</screen>
For [[a.out]], get [[tools-]]'''n.nn'''[[.tar.gz]]
from [[tsx-11.mit.edu/pub/linux/packages/GCC/src/]]. It
comes with documentation that will tell you what to do. Note that
[[a.out]] shared libraries are a very tricky business.
Consider upgrading your libraries to <acronym>ELF</acronym> shared libraries.
See the <citetitle>ELF HOWTO</citetitle>, at
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/]].
Q: Why Are My Programs So Large?|executables-are-very-large
A: With an <acronym>ELF</acronym> compiler ([[link:about-elf-glibc]]),
the most common
cause of large executables is the lack of an appropriate .so library link for
one of the libraries you're using. There should be a link like
[[libc.so]] for every library like [[libc.so.5.2.18]].
With an [[a.out]] compiler the most common cause of large
executables is the <command>-g</command> linker (compiler) flag. This
produces (as well as debugging information in the output file) a program
which is statically linkedone which includes a copy of the C library instead
of a dynamically linked copy.
Other things worth investigating
are <command>-O</command> and <command>-O2</command>, which enable
optimization (check the GCC documentation), and -s (or the strip command)
which strip the symbol information from the resulting binary (making
debugging totally impossible).
You may wish to use -N on very
small executables (less than 8K with the -N), but you shouldn't do this
unless you understand its performance implications, and definitely never with
daemons.
Q: How To Prevent Errors when Linking Programs with Math Functions|math-lib-errors
A: Older run-time libraries included the math library in the C run-time library.
It was not necessary to specify the math library separately when compiling.
If the compiler generates a message like this when linking a program that uses math functions:
<screen> /tmp/ccDUQM4J.o: In function "main":
/tmp/ccDUQM4J.o(.text+0x19): undefined reference to "sqrt"
collect2: ld returned 1 exit status </screen>
You need use the <literal>-lm</literal> option with GCC to link with the math libraries:
<screen> # gcc -o program program.c -lm </screen>
Make sure also to use the statement <literal>#include
&lt;math.h&gt;</literal> in the source file.
[Florian Schmidt]
Q: How To Program '''XYZ''' Under Linux|program-xyz-under-linux
A: Read the manuals, or a good book on Unix and the manual pages (type <literal>man man</literal>).
There is a lot of GNU Info documentation, which is often more useful as a
tutorial. Run Emacs and type
<keycombo><keycap>F1</keycap><keycap>i</keycap></keycombo>, or type
<command>info info</command> if you don't have or don't like Emacs. Note that
the Emacs libc node may not exactly describe the latest Linux libc, or GNU
glibc2. But the GNU project and LDP are always looking for volunteers to
upgrade their library documentation.
Anyway, between the
existing Texinfo documentation, and the manual pages in sections 2 and 3,
should provide enough information to get started.
As with all free software, the best tutorial is the source code itself.
The latest release of the Linux manual pages, a collection of useful GNU Info
documentation, and various other information related to programming Linux,
can be found on [[metalab.unc.edu/pub/Linux/docs/man-pages/]].
Q: How To Upgrade/Recompile a Kernel|upgrade-recompile-kernel
A: See the <citetitle>Kernel HOWTO</citetitle> or the [[README]] files which come with
the kernel release on [[ftp://ftp.cs.helsinki.fi/pub/Software/Linux/Kernel/]] and
mirrors.
See [[link:get-linux-material-by-ftp]].
You may already have a version of the
kernel source code installed on your system, but if it is part of a standard
distribution it is likely to be somewhat out of date (this is not a problem
if you only want a custom configured kernel, but it probably is if you need
to upgrade.)
With newer kernels you can (and should) make all
of the following targets. Don't forget that you can specify multiple targets
with one command.
<screen> $ make clean dep install modules modules_install </screen>
Also remember to update the module
dependencies.
<screen> $ depmod -a </screen>
This command can be run automatically at boot time. On Debian/GNU Linux systems,
the command is part of the [[/etc/init.d/modutils]] script,
and can be linked appropriately in the [[/etc/rc]]'''x'''[[.d/]]
directories. For more information on <command>depmod</command>, see the
manual page.
Make sure you are using the most recent version
of the modutils utilities, as well as all other supporting packages. Refer to
the file [[Documentation/Changes]] in the kernel source tree
for specifics, and be sure to consult the [[README]] file in
the <application>modutils</application> package.
Remember that to make the new kernel boot you must run <command>lilo</command> after
copying the kernel into your root partition. The Makefile in some kernels
have a special <literal>zlilo</literal> target for this; try:
<screen> $ make zlilo </screen>
On current systems, however, you can simply copy the [[zImage]] or
[[bzImage]] file (in [[arch/i386/boot/]] to
the [[/boot/]] directory on the root file system, or to a
floppy using the <command>dd</command> command. Refer also to the question,
How do I get LILO to boot the kernel image?
Kernel version numbers with an odd minor version (ie, 1.1.x, 1.3.x) are the testing
releases; stable production kernels have even minor versions (1.0.x, 1.2.x).
If you want to try the testing kernels you should probably subscribe to the
linux-kernel mailing list.
See [[link:what-mailing-lists-are-there]].
The Web site [[http://www.kernelnotes.org/]] has lots of
information and links to other sites that provide information about Linux
kernel updates.
Also refer to the answers for,
[[link:upgraded-kernel-pcmcia-doesnt-work]] and
[[link:lilo-boot-kernel-image]].
A: Alternatively, on Debian GNU/Linux systems, get a kernel source package
from the Debian archive or from a Debian GNU/Linux CD. Then, follow the
directions in the [[file:README]] file that is located in the [[dir:kernel-package]]
subdirectory.
Q: What Is a <literal>.gz</literal> File? And a <literal>.tgz</literal>? And <literal>.bz2</literal>? And... ?|What-is-a-gz-file-tgz
A: <literal>.gz</literal> (and <literal>.z</literal>) files are compressed using GNU
<command>gzip</command>. You need to use <command>gunzip</command> (which is
a symlink to the <command>gzip</command> command that comes with most Linux
installations) to unpack the file.
<literal>.taz</literal>, <literal>.tar.Z</literal>, and <literal>.tz</literal> are
'''tar''' files (made with <command>tar</command>) and
compressed using <command>compress</command>. The standard *nix
<command>compress</command> is proprietary software, but free equivalents
like ncompress exist.
<literal>.tgz</literal> (or <literal>.tpz</literal>) is a tar file compressed with
<command>gzip</command>.
<literal>.bz2</literal> is a file compressed by the more recently introduced (and efficient)
<command>bzip2</command>.
<literal>.lsm</literal> is a <citetitle>Linux Software Map</citetitle> entry, in the form of a short text
file. Details about the LSM project and the LSM itself are available in the
subdirectory on [[ftp://metalab.unc.edu/pub/Linux/docs/]].
<literal>.deb</literal> is a Debian Binary Package - the binary package
format used by the Debian GNU/Linux distribution. It is manipulated using
<command>dpkg</command> and <command>dpkg-deb</command>
(available on Debian systems and from:
[[http://ftp.debian.org/pool/main/d/dpkg/]].
If you use anonymous FTP, connect to:
[[ftp://ftp.debian.org/debian/pool/main/d/dpkg/]]).
<literal>.rpm</literal> is a Red Hat RPM package, which is used in the Red
Hat and similar distributions.
<literal>.sit</literal> is a compressed Macintosh archive made with StuffIt, a commercial program.
Aladdin Systems Inc., the manufacturer of StuffIt, has a free expander utility that
will uncompress these archives. You can download it at
[[http://www.aladdinsys.com/expander/]].
The <command>file</command> command can often tell you what a file is.
If you find that <command>gzip</command> complains when you
try to uncompress a file, you probably downloaded it in ASCII mode by
mistake. You must download most things in binary mode:
<literal>get</literal>, to download the file.
Q: Where Are [[linux/*.h]] and [[asm/*.h]]?|linux-h-and-asm-h
A: The files [[/usr/include/linux/]] and [[/usr/include/asm/]]
are often soft links to the
directories where the kernel headers are. They are usually under
[[/usr/src/kernel*/]].
If you don't have the kernel sources, download them. Refer to the answer for
[[link:upgrade-recompile-kernel]].
Then, use <command>rm</command> to remove any garbage, and
<command>ln</command> to create the links:
<screen> $ rm -rf /usr/include/linux /usr/include/asm
$ ln -sf /usr/src/linux/include/linux /usr/include/linux
$ ln -sf /usr/src/linux/include/asm-<architecture> /usr/include/asm</screen>
The assembly language files reside in architecture-specific directories, so you need to link
<literal>/usr/src/include/asm</literal> to
<literal>/usr/src/linux/include/asm-i386</literal> on PC compatible systems,
to <literal>/usr/src/linux/include/asm-sparc</literal> on Sun Sparc systems,
to <literal>/usr/src/linux/include/asm-ppc</literal> on PPC systems, and so
on.
You'll also find that you may need to do "make config" as
in a newly-unpacked kernel source tree, to create
[[linux/autoconf.h]].
Q: Configuring <application>Emacs</application>' Default Settings|configure-emacs-with-default
A: Create a file in your home directory named [[dir:.emacs]] with the Emacs
Lisp commands that you want to run every time Emacs starts up. You won't see
the file in the directory listing. (The leading '.' tells
<command>ls</command> not to display it, unless you use the
<literal>-a</literal> command line switch with <command>ls</command>.)
Any kind of Emacs Lisp statement will work in the
[[.emacs]] file, including entire <literal>defuns</literal>.
Emacs uses lisp variables and statements extensively, and many of the editing
functions are written in Emacs Lisp. For example, to enable word wrapping
whenever you edit a file that ends with [[.txt]], add the
following statement. This is from the Emacs Texinfo help document (
<keycombo><keycap>F1</keycap><keycap>i</keycap></keycombo>, then
<keycap>m</keycap> <literal>Emacs</literal> <keycap>Return</keycap>):
<programlisting> (add-hook text-mode-hook
'(lambda () (auto-fill-mode1)))</programlisting>
This adds a statement that calls a
'''hook''' function whenever a text editing mode is entered
for that buffer. The value of <literal>text-mode-hook</literal>, which is a
variable, to <literal>auto-fill-mode</literal>, which is a function.
If you want to turn off the menu bar at the top of each Emacs frame,
add this statement:
<programlisting> (menu-bar-mode -1)</programlisting>
And if you want to include an Emacs Lisp
program that someone has written, like [[msb.el]] (an
enhanced, pop-up buffer menu), make sure the lisp file is in a directory
where Emacs can find it (usually it will be named Site-lisp), and add these
statements in the [[.emacs]] file:
<programlisting> (require 'msb)
(msb-mode 1) </programlisting>
Most tasks have several possible solutions in Emacs Lisp. Any task that can
be programmed in Emacs Lisp is valid in the [[.emacs]] file.
For more information, consult the Texinfo documentation. There is also a FAQ
list for Emacs (refer to: What other FAQ's are there for Linux? ).
=Solutions to Common Problems|common-problems=
Q: How Do I Remove (or Change) the Colors in the <application>ls</application> Display?|ls-colors
A: If <command>ls</command> is displaying in color and you haven't told it to, you probably have an alias configured for it. Some distributions ship this way by default.
The shell command, <literal>unalias ls</literal>, should completely unset the
configuration that some distributions provide as standard.
To permanently make this change, check your initialization script, [[.bashrc]].
A: To change the colors, rather than removing them, refer to the <application>ls</application> man page
(<literal>man ls</literal>).
Q: Why Won't a Program Work in the Current Directory?|programs-in-cwd
A: Because the current directory (i.e.,
<literal>.</literal>) is not in the search path, for security reasons, as
well as to insure that the correct program versions are used. If an intruder
is able to write a file to a world-writable directory, like
[[/tmp]], presumably he or she would be able to execute it
if the directory were in the search path. The solution to this is to include
the directory in the command; e.g., <literal>./myprog</literal>, instead
of <literal>myprog</literal>. Or add the current directory to your
<literal>PATH</literal> environment variable; e.g., <literal>export
PATH=".:"$PATH</literal> using <application>bash</application>, although
this is discouraged for the reasons mentioned above.
Q: How Do I Find Out If a Notebook Runs Linux?|my-notebook-runs-linux
A: There's no fixed answer to this question,
because notebook hardware is constantly updated, and getting the X display,
sound, PCMCIA, modem, and so forth, working, can take a good deal of effort.
Most notebooks currently on the market, for example, use
"Winmodems," which often do not work with Linux because of their
proprietary hardware interfaces. Even notebooks which are certified as
"Linux compatible," may not be completely compatible.
Information about installing Winmodems in general is contained in the
[[ldp:Winmodems-and-Linux-HOWTO]].
Refer to [[link:howtos-and-other-documentation]].
You can find the most current information, or ask other users about their notebook
experiences, on the linux-laptop mailing list, which is hosted by the
<literal>vger.redhat.com</literal> server.
Refer to [[link:what-mailing-lists-are-there]].
A mailing list for Linux on IBM Thinkpads has its home page at
[[http://www.topica.com/lists/linux-thinkpad/]].
Another Thinkpad mailing list is hosted by [[http://www.bm-soft.com/]].
Send email with the word <literal>help</literal> in the body of the message to
[[mailto:majordomo@www.bm-soft.com]].
There is a Web page about Linux on IBM Thinkpads at [[http://peipa.essex.ac.uk/tp-linux/]].
The Linux Laptop home page is at [[http://www.cs.utexas.edu/users/kharker/linux-laptop/]].
For information about interfacing peripherals like
Zip and CD-ROM drives through parallel ports, refer to the Linux Parallel
Port Home Page, at [[http://www.torque.net/linux-pp.html]].
If you need the latest version of the PCMCIA Card Services package, it
is (or was) located at [[ftp://cb-iris.stanford.edu/pub/pcmcia/]], but that
host no longer seems to be available. Recent distributions are on
[[ftp://metalab.unc.edu/pub/Linux/kernel/pcmcia/]].
You will also need to have the kernel source code installed as well. Be sure
to read the [[ldp:PCMCIA-HOWTO]], which is included in the
distribution.
Q: Can Can I Resume an Interrupted Download?|resume-ftp
A: You can use the <literal>reget</literal> command of the
standard <command>ftp</command> client program after reconnecting to pick up
where you left off.
Clients like <command>ncftp</command>
support resumed FTP downloads, and <command>wget</command> supports resumed
FTP and HTTP downloads.
=Tips And Tricks|tips=
Q: How Do I Format Man Pages without <command>man</command> or <command>groff</command>?|man-pages-without-man
A: The <command>man2html</command> program translates <command>groff</command>
text to HTML, which you can view with a Web browser. The
<command>man2html</command> program, and many like it, are availble on the
Web. Look for them with your favorite search engine.
The unformatted manual pages are stored in subdirectories of
[[/usr/man]], [[/usr/local/man]], and
elsewhere.
If you want to view text, use <command>nroff</command> and <command>less</command>.
Both of these programs have MSDOS versions with an implementation of the '''man'''
macro package available as well. An example would be:
<screen> $ nroff -man /usr/man/man1/ls.1 | less </screen>
If you know where to find a good implementation of the '''man''' macros
without installing '''groff''', please let the FAQ maintainer
know.
If the manual page filename ends in <literal>.gz</literal>, then you'll need to
uncompress it before formatting it, using <command>gzip -d</command> or <command>gunzip</command>.
A one-line example would be:
<screen> $ gzip -dc /usr/man/man1/ls.1.gz | nroff -man | less </screen>
Q:How To Scroll Backwards in Text Mode|scrollback-in-text-mode
A: With the default US keymap, you can
use <keycap>Shift</keycap> with the <keycap>PgUp</keycap> and
<keycap>PgDn</keycap> keys. (The gray ones, not the ones on the numeric
keypad.) With other keymaps, look in [[/usr/lib/keytables]].
You can remap the <keycap>ScrollUp</keycap> and <keycap>ScrollDown</keycap> keys to be whatever you like.
The <command>screen</command> program, [[http://vector.co.jp/vpack/browse/person/an010455.html]]
provides a searchable scrollback buffer and the ability to take
"snapshots" of text-mode screens.
Recent kernels that have
the VGA Console driver can use dramatically more memory for scrollback,
provided that the video card can '''actually handle''' 64 kb
of video memory. Add the line:
<screen> #define VGA_CAN_DO_64B </screen>
to the start of the file [[drivers/video/vgacon.c]]. This feature may become a
standard setting in future kernels. If the video frame buffer is also enabled
in the kernel, this setting may not affect buffering.
In older kernels, the amount of scrollback is fixed, because it is implemented using
the video memory to store the scrollback text. You may be able to get more
scrollback in each virtual console by reducing the total number of VC's. See
[[linux/tty.h]].
[Chris Karakas]
Q: How To Get Email to Work|e-mail-to-work
A: For sending mail via SMTP (Simple Mail Transfer
Protocol) and receiving mail from an ISP's POP (Post Office Protocol) server,
you can use a desktop client like Netscape Communicator or KDE kmail. You
will need to enter the names of the SMTP and POP servers in the preferences
of the respective application, as well as your E-mail address
(e.g., username@example.com), and your dial-up password. The same applies to
Usenet News. Enter the name of the NNTP (Network News Transfer Protocol)
server in your News client's preferences section. You may also have to
provide the IP addresses of the ISP's primary and secondary name servers.
If you have a traditional MTA (Mail Transport Agent) like
<application>Sendmail</application>, <application>Smail</application>,
<application>qmail</application>, or <application>Exim</application>, you'll
need to follow the instructions in each package. Basically, configuration
entails determining which host machine, either on your local LAN or via
dial-up Internet, is the "Smart Host", if you're using SMTP. If you're
using the older UUCP protocol, then you'll need to consult the directions for
configuring UUCP, and also make sure that your ISP's system is configured to
relay mail to you.
Information about Internet hosting, and
News and E-mail in general, is available on the Usenet News group
<citetitle>news.announce.newusers</citetitle>, and those FAQ's are also
archived at [[ftp://rtfm.mit.edu/pub/usenet/]].
Q: <application>Sendmail</application> Pauses for Up to a Minute at Each Command|sendmail-pause
A: Make sure that <application>Sendmail</application>
can resolve your hostname to a valid (i.e., parsable) domain address. If you
are not connected to the Internet, or have a dial-up connection with dynamic
IP addressing, add the fully qualified domain name to the
<literal>/etc/hosts</literal> file, '''in addition''' to the
base host name; e.g., if the host name is <literal>bilbo</literal> and
the domain is <literal>bag-end.com</literal>:
<screen> 192.168.0.1 bilbo.bag-end.com bilbo </screen>
And make sure that either the <literal>/etc/host.conf</literal> or <literal>
/etc/resolv.conf</literal> file contains the line:
<screen> order hosts,bind </screen>
<caution>Do not change the <literal>localhost</literal> entry in
<literal>/etc/hosts</literal>, because many programs depend on it for
internal message-passing.</caution>
<application>Sendmail</application>
takes many factors into account when resolving domain addresses. These
factors, collectively, are known as, "rulesets", in
<application>sendmail</application> jargon. The program does
'''not''' require that a domain address be canonical, or even
appear to be canonical. In the example above, <literal>bilbo.</literal>
(note the period) would work just as well as
<literal>bilbo.bag-end.com</literal>. This and other modifications apply
mainly to recent versions.
Prior to version 8.7,
<application>sendmail</application> required that the FQDN appear first in
the [[/etc/hosts]] entry. This is due to changes in the
envelope address masquerade options. Consult the
<application>sendmail</application> documents.
If you have a
domain name server for '''only''' a local subnet, make sure
that "." refers to a SOA record on the server machine, and that reverse
lookups (check by using <application>nslookup</application>) work for all
machines on the subnet.
Finally, <literal>FEATURE</literal>
configuration macro options like <literal>nodns</literal>,
<literal>always_add_domain</literal>, and <literal>nocanonify</literal>,
control how <application>sendmail</application> interprets host names.
The document, <citetitle>Sendmail: Installation and Operation
Guide</citetitle>, included in the <literal>doc/</literal> subdirectory of
<application>Sendmail</application> source code distributions, discusses
briefly how <application>Sendmail</application> resolves Internet addresses.
<application>Sendmail</application> source code archives are listed at:
[[http://www.sendmail.org/]]
[Chris Karakas]
Q: How To Enable and Select Virtual Consoles|switch-virtual-consoles
A: In text mode, press the left
<keycombo>
<keycap>Alt</keycap>
<keycap>F1</keycap>
</keycombo> to
<keycombo>
<keycap>Alt</keycap>
<keycap>F12</keycap>
</keycombo> to select the consoles
<literal>tty1</literal> to <literal>tty12</literal>; Right
<keycombo>
<keycap>Alt</keycap>
<keycap>F1</keycap>
</keycombo> gives
<literal>tty13</literal> and so on. To switch out of X you must press
<keycombo>
<keycap>Ctrl</keycap>
<keycap>Alt</keycap>
<keycap>F1</keycap>
</keycombo>, etc;
<keycombo>
<keycap>Alt</keycap>
<keycap>F5</keycap>
</keycombo> or whatever will switch back.
However, If you have a non-PC compatible system, please see the note below.
If you want to use a VC for ordinary login, it must be listed in
<citetitle>/etc/inittab</citetitle>, which controls which terminals and
virtual consoles have login prompts. The X Window System needs at least one
free VC in order to start.
<note>The key sequence is actually <keycombo> <keycap>Ctrl</keycap></keycombo> <literal>Meta</literal>
<keycombo><keycap>F</keycap></keycombo>'''N'''. On PC
compatible systems, the right and left <keycap>Alt</keycap> keys are really
synonymous with the keysymbols <literal>Meta_L</literal> and
<literal>Meta_R</literal>. If the binding is different, you can determine
what keys produce <literal>Meta_L</literal> and <literal>Meta_R</literal> with <application>xkeycaps</application> or a similar application.</note>
[David Charlap]
Q: How To Set the Time Zone|set-the-time-zone
A: Change directory to [[/usr/lib/zoneinfo/]]. Get the time zone package if you
don't have this directory. The source is available in
[[ftp://metalab.unc.edu/pub/Linux/system/admin/time/]].
Then make a symbolic link named [[localtime]]
pointing to one of the files in this directory (or a subdirectory), and one
called [[posixrules]] pointing to
[[localtime]]. For example:
<screen> $ ln -sf US/Mountain localtime
$ ln -sf localtime posixrules </screen>
This change will take effect immediatelytry <command>date</command>.
If the system uses Red Hat-style configuration files, the respective
time zone info files are [[/usr/share/zoneinfo]] and
[[/etc/localtime]].
The manual pages for <command>tzset</command> or <command>tzselect</command> describe setting the
time zone. Some programs recognize the <literal>TZ</literal> environment
variable, but this is not POSIX-correct.
You should also make sure that your Linux kernel clock is set to the correct GMT time. Type
<command>date -u</command> and check that the correct UTC time is displayed.
See [[link:computer-has-wrong-time]].
Q:What Is a [[core]] File?|core-file
A: A <literal>core</literal>
file is created when a program terminates unexpectedly, due to a bug, or a
violation of the operating system's or hardware's protection mechanisms. The
operating system kills the program and creates a [[core]]
file that programmers can use to figure out what went wrong. It contains a
detailed description of the state that the program was in when it died.
If would like to determine what program a core file came from,
use the <literal>file</literal> command, like this:
<screen> $ file core </screen>
That will tell you the name of the program
that produced the core dump. You may want to write the maintainer(s) of the
program, telling them that their program '''dumped core.'''
[Eric Hanchrow]
Q: How To Enable or Disable Core Dumps|enable-core-dumps
A: By using the <command>ulimit</command> command in
<command>bash</command>, the <command>limit</command> command in
<command>tcsh</command>, or the <command>rlimit</command> command in
<command>ksh</command>. See the appropriate manual page for details.
This setting affects all programs run from the shell (directly or
indirectly), not the whole system.
If you wish to enable or disable core dumping for all processes by default,
you can change the default setting in [[linux/sched.h]]. Refer to definition of
<literal>INIT_TASK</literal>, and look also in
[[linux/resource.h]].
PAM support optimizes
the system's environment, including the amount of memory a user is allowed.
In some distributions this parameter is configurable in the
<literal>/etc/security/limits.conf</literal> file. For more information,
refer to the <citetitle>Linux Administrator's Security Guide</citetitle>.
See [[link:howtos-and-other-documentation]].
Q: How To Remap a Keyboard to UK, French, Etc.|remap-keyboard
A: For recent kernels, get [[/pub/Linux/system/Keyboards/kbd-0.90.tar.gz]] from
[[ftp://metalab.unc.edu/]].
Make sure you get the appropriate version; you have to use the right keyboard
mapping package for your kernel version.
For older kernels you have to edit the top-level kernel
[[Makefile]], in [[/usr/src/linux/]].
You may find more helpful information in <citetitle>The Linux Keyboard and
Console HOWTO</citetitle>, by Andries Brouwer, at
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/]].
Q: How To Get NUM LOCK to Default to On|num-lock-default-on
A: Use the <command>setleds</command> program, for
example (in [[/etc/rc.local]] or one of the
[[/etc/rc.d/*]] files):
<programlisting> for t in 1 2 3 4 5 6 7 8
do
setleds +num < /dev/tty$t > /dev/null
done
</programlisting>
<command>setleds</command> is part of the
kbd package ("How do I remap my keyboard to UK, French, etc.? ").
Alternatively, patch your kernel. You need to arrange for
<literal>KBD_DEFLEDS</literal> to be defined to
(<literal>1 &lt;&lt; VC_NUMLOCK</literal>) when compiling
[[drivers/char/keyboard.c]].
Q: How To Set (Or Reset) Initial Terminal Colors|set-terminal-colors
A: The following shell script should
work for VGA consoles:
<programlisting> for n in 1 2 4 5 6 7 8;
do
setterm -fore yellow -bold on -back blue -store > /dev/tty$n
done
</programlisting>
Substitute your favorite colors, and use
[[/dev/ttyS$n]] for serial terminals.
To make sure they are reset when people log out (if they've been changed):
Replace the references to <literal>getty</literal> (or
<literal>mingetty</literal> or <literal>uugetty</literal> or whatever) in
[[/etc/inittab]] with references to
<literal>/sbin/mygetty</literal>.
<programlisting> #!/bin/sh setterm -fore yellow -bold on -back blue -store > $1
exec /sbin/mingetty $@
</programlisting>
[Jim Dennis]
Q: How To Have More Than 128Mb of Swap|more-than-128mb-of-swap
A: Use several swap partitions or swap files.
Linux kernels before version 2.2 supported up to 16 swap areas, each of up to
128Mb. Recent versions do not have this limitation.
Very old kernels only supported swap partition sizes up to 16Mb.
Linux on machines with 8KB paging, like Alpha and Sparc64, support a swap partition
up to 512MB. The 128MB limitation comes from
<literal>PAGE_SIZE*BITSPERBYTE</literal> on machines with 4KB paging, but is
512KB on machines with 8KB paging. The limit is due to the use of a single
page allocation map.
The file [[mm/swapfile.c]] has all of the gory details.
[Peter Moulder, Gordon Weast]
=The X Window System|x-windows=
Q: Does Linux Support X?|linux-support-x
A: Yes. Linux uses XFree86 (the current version is 4.0, which is based on X11R6). You need
to have a video card which is supported by XFree86. See the
<citetitle>XFree86 HOWTO</citetitle> for more details.
Most Linux distributions nowadays come with an X installation. However, you
can install or upgrade your own, from
[[ftp://metalab.unc.edu/pub/Linux/X11/]]
and its mirror sites, or from [[http://www.xfree86.org/]].
Q: How To Get the X Window System to Work|get-x-window-system-work
A: The answers to this question can, and
do, fill entire books. If the installation program wasn't able to configure
the X server correctly, Linux will most likely try to start the X display,
fail, and drop back into text-only terminal mode.
First and foremost, make certain that you have provided, as closely as possible, the
correct information to the installation program of your video hardware: the
video card and monitor. Some installation programs can correctly guess a
"least common denominator" screen configuration, like a 640-by-480
VESA-standard display, but there are many possible video hardware
configurations that may not be able to display this standard.
The X Window System configuration file is called (usually) [[/etc/XF86Config]],
[[/etc/X11/XF86Config]], or
[[/usr/X11R6/lib/X11/XF86Config]].
If you need to manually configure the X server, there are several possible methods:
*Try to use the <command>XF86Setup</command> program, which can help identify the correct X
server and monitor timings for the video hardware.
*Make sure that the X server has the correct options. If you
log in as the superuser, you should be able to use <literal>X
--probeonly</literal> to get a listing of the video card chipset, memory, and
any special graphics features. Also, refer to the manual page for the X
server. (E.g.; <literal>man X</literal>), and try running the X server and
redirecting the standard error output to a file so you can determine, after
you can view text on the screen again, what error messages the server is
generating; e.g., <literal>X 2>x.error</literal>.
*With that information, you should be able to safely refer to
one of the references provided by the Linux Documentation Project. ("Where
can I get the HOWTO's and other documentation? ") There are several HOWTO's
on the subject, including a HOWTO to calculate video timings manually if
necessary. Also, the <citetitle>Installation and Getting Started</citetitle>
guide has a chapter with a step-by-step guide to writing a
[[XF86Config]] file.
/*
Also, make sure that the problem really is an incorrect
[[XF86Config]] file, not something else like the window
manager failing to start. If the X server is working correctly, you should be
able to move the mouse cursor on the screen, and pressing
<keycombo><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>Backspace</keycap></keycombo>
will shut down the X server and return to the shell prompt in one of the
virtual terminals.
Q: Where To Find a Ready-Made [[XF86Config]] file|ready-made-xf86config
A: If you can't seem to get X working using the guidelines above, refer to the
<citetitle>XFree86 HOWTO</citetitle>, recent versions of
<citetitle>Installation and Getting Started</citetitle>, and the instructions
for the <command>XF86Setup</command> 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 <command>XF86Setup</command> 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 [[news:comp.os.linux.x]] asking for an
[[XF86Config]], and please don't answer such requests.
If you have a laptop, look at the Linux Laptop Web page at
[[link:my-notebook-runs-linux]].
Many of
the installation notes also have the [[XF86Config]] file for
the display. If you have a desktop machine, there are a few sample
[[XF86Config]] files at [[ftp://metalab.unc.edu/]]. Refer also to the
<citetitle>XFree86 FAQ</citetitle> [[http://www.xfree.org/FAQ/]] and the monitor timings
list [[http://www.xfree.org/#resources/]], and in the
[[/usr/X11R6/lib/X11/]] directory of your X distribution.
Q: What Desktop Environments Run on Linux?|what-desktop-environments
A: Linux with XFree86 supports the
KDE, GNOME, and commercial CDE desktop environments, and extended window
managers like WindowMaker. 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 Trolltech at [[http://www.trollTech.com]].
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 window managers like
Enlightenment, [[http://www.enlightenment.org]]
and SawFish, [[http://www.sawfish.org/]].
There's also a Web page for <application>Red Carpet</application>, a
GNOME installation and upgrade utility that functions much like Debian's
<command>apt-get</command> utility with a friendly GUI front end.
It's at [[http://www.ximian.com/products/redcarpet]].
The commercial CDE environment uses the Motif libraries and a variation of
the Motif <command>mwm</command> window manager, <command>dtwm</command>, and
provides a suite of desktop and
session-management utilities. Several vendors have made the source
code of Motif available and provided binary packages for Linux
distributions. As a starting point, download and installation
information is available at [[http://www.opengroup.org/openmotif/]].
A free version of Motif, called LessTiF, is available from
[[http://www.lesstif.org/]].
WindowMaker, [[http://www.windowmaker.org/]] is a window manager that
has many desktop environment-like features. It provides support for
GNUstep, [[http://www.gnustep.org/]], a clone of the
commercial NeXTStep environment.
Q: <command>xterm</command> Logins Show Up Strangely in <command>who</command>, <command>finger</command>|xterm-logins-show-strangely
A: The <command>xterm</command> that comes with XFree86 2.1 and
earlier doesn't correctly understand the format that Linux uses for the
<filename>/var/adm/utmp</filename> file,
where the system records who is logged in. It therefore doesn't set
all the information correctly.
The <application>xterms</application> in XFree86 3.1 and later versions
fix this problem.
Q: How to Start a X Client on Another Display|detach-xterm
A: To start a X client on another system that has a running X
server, use the following commands:
*Use <application>xhost</application> on the server system
to allow the client system use the display. If the server's
IP address is 192.168.20.1, enter the command:
<screen>$ xhost + 192.168.20.1</screen>
*On the client system, open a telnet connection to the server system.
*In the telnet session, start a <application>xterm</application> in
the background with the <literal>-display</literal> and
<literal>-e</literal> options. For example, if the IP address of
the machine running the server is 192.168.20.1 and the client
program name is named <command>clientapp</command>, use the following command:
<screen> $ xterm -display 192.168.20.1 -e clientapp &</screen>
/*
[Pierre Dal Farra]
=Frequently Encountered Error Messages|error-messages=
Q: <command>Modprobe</command> Can't Locate Module, '''XXX''', and Similar Messages|modprobe-cant-locate-module
A: These types of messages mostly occur at boot time or shutdown.
If modprobe, insmod, or rmmod complain about not being
able to find a module, add the following to the
[[/etc/modules.conf]] or
[[/etc/modutils/aliases]] file, whichever is present on your
system.
<screen> $ alias <module-name> off </screen>
And use the name of the module that appears in the error message.
[J.H.M. Dassen]
Q: Unknown Terminal Type <literal>linux</literal> and Similar|unknown-terminal-type
A: In early kernels the default console terminal type has changed from <literal>console</literal>
to <literal>linux</literal>. You must edit
[[/etc/termcap]] to change the line reading:
<screen> console|con80x25: </screen>
to
<screen> linux|console|con80x25: </screen>
(there may be an additional <literal>dumb</literal> in there - if so it should be
removed.)
To get the editor to work you may need type:
<screen> $ TERM=console </screen>
(for <command>bash</command> and <command>ksh</command>), or
<screen> $ setenv TERM console </screen>
for <command>csh</command> or <command>tcsh</command>.
Some programs use [[/usr/lib/terminfo]] instead of
[[/etc/termcap]]. For these programs you should upgrade your
terminfo package, which is part of ncurses.
The same is true for X terminal displays. If your distribution sets the
<literal>TERM</literal> to something strange like
<literal>xterm-24-color</literal>, you can simply reset it to a generic value
from the command line:
<screen> $ TERM="xterm"; export TERM </screen>
Q: <literal>INET: Warning: old style ioctl... called!</literal>|inet-warning-old-style
A: You are trying to use the old network configuration utilities. The new ones can be found on
[[ftp://ftp.linux.org.uk/pub/linux/Networking/PROGRAMS/NetTools/]] (source only, I'm afraid).
Note that they cannot be used just
like the old-style programs. See the <citetitle>NET-2 HOWTO</citetitle> for
instructions on how to set up the old-style networking programs correctly.
Even better, see the <citetitle>NET-3 HOWTO</citetitle> and upgrade your
networking software.
Q: <literal>ld: unrecognized option '-m486'</literal>|ld-unrecognized
A: You have an old version of <command>ld</command>.
Install a newer binutils package that contains an
updated <command>ld</command>. Look on tsx-11.mit.edu in
[[/pub/linux/packages/GCC/]] for
[[binutils-2.6.0.2.bin.tar.gz]].
Q: GCC Says, <literal>Internal compiler error</literal>.|gcc-says
A: If the fault is repeatable (i.e.,
it always happens at the same place in the same file - even after rebooting and
trying again, using a stable kernel) you have discovered a bug in GCC. See
the GCC Info documentation (type
<keycombo><keycap>F1</keycap><keycap>i</keycap></keycombo> in Emacs, and
select GCC from the menu) for details on how to report the error. Make sure
you have the latest version, though.
Note that this is
probably not a Linux-specific problem. Unless you are compiling a program
many other Linux users also compile, you should not post your bug report to
any of the comp.os.linux groups.
If the problem is not
repeatable, you may be experiencing memory corruption. Refer to the answer for
[[link:make-says]].
Q: Make Says, <literal>Error 139.</literal>|make-says
A: Your compiler (GCC) dumped core. You probably
have a corrupted, buggy, or old version of GCC - get the latest release or
EGCS. Alternatively, you may be running out of swap space. Refer to
[[link:machine-runs-very-slowly-when]].
If this doesn't fix the problem, you are probably having problems with memory or disk
corruption. Check that the clock rate, wait states, and refresh timing for
your SIMMS and cache are correct (hardware manuals are sometimes wrong, too).
If so, you may have some marginal SIMMS, or a faulty motherboard or hard disk
or controller.
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 (see [[link:upgrade-recompile-kernel]]).
The <literal>no387</literal> 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/]].
Q: Shell-Init: Permission Denied when I Log In|shell-init-permission
A: Your root directory and all the
directories up to your home directory must be readable and executable by
everybody. See the manual page for <command>chmod</command> or a book on Unix
for how to fix the problem.
Q: No Utmp Entry. You Must Exec ... when Logging In|no-utmp-entry
A: Your [[/var/run/utmp]] is screwed up. You should have
<screen> /var/run/utmp</screen>
in your [[/etc/rc.local]] or [[/etc/rc.d/*]].
See [[link:screwed-up-system-and-cant-log-in]].
Note that the [[utmp]] may also be found in [[/var/adm/]]
or [[/etc/]] on some older systems.
Q: Warning--bdflush Not Running|warning--bdflush
A: Modern kernels use a better strategy for writing
cached disk blocks. In addition to the kernel changes, this involves
replacing the old <command>update</command> program which used to write everything every 30
seconds with a more subtle daemon (actually a pair), known as
<command>bdflush</command>. Get
[[bdflush-]]'''n.n'''[[.tar.gz]]
from the same place as the kernel source code
(see [[link:upgrade-recompile-kernel]]) and
compile and install it. <command>bdflush</command> 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 <command>update</command> around.
Q: <literal>Warning: obsolete routing request made</literal>|warning-obsolete-routing
A: This is nothing to worry about. The message means that your version <command>route</command> is
a little out of date, compared to the kernel. You can make the message go
away by getting a new version of <command>route</command> from the same place
as the kernel source code.
See [[link:upgrade-recompile-kernel]].
Q: <literal>EXT2-fs: warning: mounting unchecked file system</literal>|ext2-fs-warning-mounting
A: You need to run <command>e2fsck</command> (or <literal>fsck -t ext2</literal> if you have
the <command>fsck</command> front end program) with the <command>-a</command>
option to get it to clear the <literal>dirty</literal> flag, and then
cleanly unmount the partition during each shutdown.
The easiest way to do this is to get the latest <command>fsck</command>,
<command>umount</command>, and <command>shutdown</command> commands,
available in Rik Faith's [[util-linux]] package
(see [[link: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
<screen> VFS: mounted root ... read-only </screen>
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. Almost all
distributions do this. If your's doesn't, read the documentation that comes
with [[util-linux]] to find out how to do this.
Note that you need to specify the <command>-n</command> option to
<command>mount</command> 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.
Q: <literal>EXT2-fs warning: maximal count reached</literal>|ext2-fs-maximal
A: 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.
See [[link:get-linux-material-by-ftp]].
The maximal number of mounts value can be examined and changed using the
<command>tune2fs</command> program from this package.
Q: <literal>EXT2-fs warning: checktime reached</literal>|ext2-fs-warning
A: 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.
See [[link:ext2-fs-maximal]].
Q: <command>df</command> Says, <literal>Cannot read table of mounted file systems</literal>.|df-says-cannot
A: 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
<screen> $ rm -f /etc/mtab*</screen>
Some old Linux distributions have an entry for the
root partition in [[/etc/mtab]] made in
[[/etc/rc*]] by using <command>rdev</command>. That is
incorrectthe newer versions of <command>mount</command> do this
automatically.
Some old distributions also have a line in
[[/etc/fstab]] that looks like:
<screen>/dev/sdb1 /root ext2 defaults</screen>
The entry for [[/root]] should read simply [[/]].
Q: <command>fdisk</command> Says, "<literal>Partition X has different physical/logical...</literal>"|fdisk-says-partition
A: If the partition number (X, above) is 1, this is the same problem as in <literal>fdisk: Partition 1 does
not start on cylinder boundary</literal>.
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 [[link:linux-to-work-with-my-disk]].
Q: <literal>fdisk: Partition 1 does not start on cylinder boundary</literal>|fdisk-partition-does-not
A: The version of <command>fdisk</command> 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 <command>fdisk</command>, 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 <command>fdisk</command> likes.
*Create partition 1 in the normal way. A
<literal>p</literal> listing will produce the mismatch complaint.
*Type <keycap>u</keycap> to set sector
mode and do <keycap>p</keycap> again. Copy down the number from the
<literal>End</literal> 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
<keycap>p</keycap> output. Set the last sector to the value you wrote down in
the step above.
*Type <keycap>u</keycap> 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.
/*
Q: <command>fdisk</command> Says Partition '''n''' Has an Odd Number of Sectors|fdisk-odd-number-sectors
A: 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.
Q: Mtools Utilities Say They Cannot Initialize Drive '''X'''|mtools-cannot-initialize
A: 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 <command>chmod</command>
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? Noteyou should never use mtools to access files on
an msdosfs mounted partition or disk!
Q: At the Start of Booting: <literal>Memory tight</literal>|memory-tight
A: 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.
See [[link:upgrade-recompile-kernel]].
Q: The System Log Says, <literal>end_request: I/O error</literal>, ....|my-syslog-says-end-request
A: 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 home
brew systems. If you install an IDE drive, '''always''' use
new ribbon 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 Ts'o]
Q: <literal>You don't exist. Go away.</literal>|you-don-t-exist
A: This is not a viral infection. It comes
from programs like <command>write</command>, <command>talk</command>, and
<command>wall</command>, 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).
Q: <literal>Operation not permitted</literal>.|chattr
A: One or more of the file's or
directory's attribute bits are set incorrectly. If the
<literal>I</literal> bit is set, for example, you won't be able to change
file permissions with <command>chmod</command>.
The solution is to use <command>lsattr</command> to display file and directory attributes,
and <command>chattr</command> to set and unset them. The programs'
documentation is contained in their manual pages.
[Paul Campbell]
Q: '''programname: ''' <literal>error in loading shared libraries: lib</literal> '''xxx.'''<literal>.so.</literal> '''x'''<literal>: cannot open shared object file: No such file or directory.</literal>
A: A message like this, when the program
that you're trying to run uses shared libraries, usually means one of two
things: the program was either compiled on a machine that had a different set
of libraries or library paths than yours; or you've upgraded your libraries
but not the program.
Executable programs that are linked with
dynamic libraries, expect the full pathname of each of the library files it
requires. So do the shared libraries, if they rely on other libraries. This
is so the shared object dependencies remain as unambiguous as possible, and
also as a security measure.
Short of recompiling the executable file for the libraries on the systemprobably the most desirable
alternative in the long run - you can try to determine which libraries the
executable file needs with the command: <literal>ldd</literal> '''programname'''.
The output will be a list of
the shared libraries on the system that the program needs to run, as well as
the missing libraries. You can then add the library packages, or if the
libraries already exist in a different directory, you can create a symbolic
link so the program can find it. For example, if the program requires
/usr/lib/libncurses.so.2, and your machine has /lib/libncurses.so.2, you can
create a link where the program expects to find the library; e.g.:
<screen> # cd /usr/lib &amp;&amp; ln -s /lib/libncurses.so.2 . </screen>
You should note, however, that creating library links like
these should be considered a security risk, and the additional links you
create will not be compatible with future upgrades. It's simply a quick fix
for backward compatibility.
Also, it may take some guesswork
to determine in exactly which of the system library directories the program
expects to find a shared library file, because <literal>ldd</literal> will
not list the paths of libraries it can't find. A program most likely will
tell the run-time linker, <literal>/lib/ld.so</literal>, to look for shared
libraries in [[/lib]], [[/usr/lib]], [[/usr/local/lib]], or [[/usr/X11R6/lib]],
if it's an X client. But that doesn't mean that libraries can't be installed
elsewhere. It helps to have some idea of the original library configuration
before proceeding.
Also be sure to run <literal>ldconfig</literal> after creating the symbolic link, so that
<literal>ld.so</literal> has an updated view of the system's libraries. You
should also make certain that all of the library directories are listed in
[[/etc/ld.so.conf]], and perhaps in the
<literal>LD_LIBRARY_PATH</literal> environment variable.
Q: <literal> init: Id "x" respawning too fast: disabled for 5 minutes </literal>.
A: In most distributions
this means that the system is booting by default into runlevel 5, which is
supposed to respawn (re-start again after it's been exited) a graphical login
via <application>xdm</application>, <application>kdm</application>,
<application>gdm</application>, or whatever, and the system can't locate the
program.
However, <literal>Id</literal> can also indicate
the absence or misconfiguration of another program, like
<application>mingetty</application>, if <application>init</application> tries
to respawn itself more than 10 times in 2 minutes.
Id "x" is the number in the leftmost column of the [[/etc/inittab]]
file:
<screen> # Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6
</screen>
Commenting the offending line out and then fixing the
errant program and testing on the command line will allow you to see any
error messages that go to standard error output (console) if the errors are
not going to the system log file. Uncomment the line and restart
<application>init</application> with <literal>kill -SIGHUP 1</literal> or
<application>telinit q</application> to cause
<application>init</application> to reinitialize and reread the
[[/etc/inittab]] file.
Some systems, however, rewrite [[/etc/inittab]] when booting. In that case, refer
to the <literal>init</literal> man page, and/or the settings in
[[/etc/sysconfig/init]].
Refer to the <application>init</application> and [[/etc/inittab]] man
pages for detailed information.
[Carl King]
Q: FTP server says: "421 service not available, remote server has closed connection."|ftp-421-error
A: If an FTP server won't allow logins, it is probably configured correctly, but
the problem is probably with authorizing users at login. FTP servers in
current distributions often authorize users with the Pluggable Authentication
Modules library, in which case there should be an authorization file
[[/etc/pam.d/ftp]]. A generic authorization file looks like
this. (The line break on the first "auth" line is for readability. The
entry is actually a single, long line).
<screen> #%PAM-1.0
auth required /lib/security/pam_listfile.so item=user
sense=deny file=/etc/ftpusers onerr=succeed
auth required /lib/security/pam_pwdb.so shadow nullok
auth required /lib/security/pam_shells.so
account required /lib/security/pam_pwdb.so
session required /lib/security/pam_pwdb.so
</screen>
Also, make sure the [[/etc/ftpusers]] file, or whatever users file is named in
the first "auth" line, is configured correctly.
Btw, the sample [[ftp]] file above is actually
the [[ftpd/ftp.pam.sample]] file from the
[[ftpd-BSD-0.3.1.tar.gz]] package. Many thanks to David A.
Madore for this much needed port.
=Online Resources|online-resources=
Q: Where Is the Documentation?|howtos-and-other-documentation
A: Look in the following places, and the sites that mirror them.
*The Linux Documentation Project at [[http://tldp.org]] publishes
hundreds of documents on using Linux.
*[[ftp://ftp.funet.fi/pub/OS/Linux/doc/HOWTO/]]
*[[ftp://tsx-11.mit.edu/pub/linux/docs/HOWTO/]]
*[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/]]
/*
For a list of Linux FTP sites, refer to the answer for:
[[link:get-linux-material-by-ftp]].
If you don't have access to FTP, try the FTP-by-mail servers:
*[[mailto:ftpmail@decwrl.dec.com]]
*[[mailto:ftpmail@doc.ic.ac.uk]]
*[[mailto:ftp-mailer@informatik.tu-muenchen.de]]
/*
A complete list of HOWTO's is available in the
<citetitle>HOWTO-INDEX</citetitle> at
[[http://www.tldp.org/HOWTO/HOWTO-INDEX/howtos.html]].
The mini-HOWTO's are indexed at
[[http://www.tldp.org/HOWTO/HOWTO-INDEX/mini.html]].
In addition, translations are available from
[[ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/translations/]]
and mirrors worldwide. The HOWTO's and other documentation
have been translated into the following languages:
*Chinese (zh)
*Croatian (hr)
*French (fr)
*German (de)
*Hellenic (el)
*Indonesian (id)
*Italian (it)
*Japanese (ja)
*Korean (ko)
*Polish (pl)
*Slovenian (sl)
*Spanish (es)
*Swedish (sv)
*Turkish (tr)
/*
Additional documents are always in preparation. Please get in touch with the
coordinators if you are interested in writing one. Contact and submission
information is at [[http://tldp.org/mailinfo.html]].
There is also a LDP HOWTO page at [[http://howto.tucows.org/]].
The Guide Series produced by the Linux Documentation Project is available
from [[http://tldp.org]].
Please read them if you are new to Unix and Linux.
And, of course, a number of people have written documentation independently of the LDP:
*<citetitle>Linux Administrators Security Guide,</citetitle> by Kurt
Seifried. [[http://www.freek.com/lasg/]].
*<citetitle>Newbie's Linux Manual.</citetitle> [[http://tldp.org/nlm/]].
*<citetitle>One-Page Linux Manual.</citetitle> [[http://www.powerup.com.au/~squadron/]].
*<citetitle>Rute Users Tutorial and Exposition.</citetitle> [[http://rute.sourceforge.net]]
*<citetitle>Short beginners' manual for Linux.</citetitle> Also available in Dutch. [[http://www.stuwww.kub.nl/people/b.vannunen/linux-man.php3]].
*<citetitle>Virtual Frame buffer HOWTO,</citetitle> by Alex Buell. [[http://www.tahallah.demon.co.uk/programming/prog.html]]
*<citetitle>X11 &amp; TrueType Fonts,</citetitle> by Peter Kleiweg. [[http://www.let.rug.nl/~kleiweg/]].
/*
Documentation for kernel developers is on-line: [[http://kernelbook.sourceforge.net]].
To find out about Linux memory management, including performance tuning, see
Rik van Riel's Web page at [[http://humbolt.geo.uu.nl/Linux-MM/]].
The Linux [[Consultants-Guide]] has a directory of Linux consultants.
Gary's Encyclopedia lists over 4,000 Linux related links. Its URL is
[[http://members.aa.net/~swear/pedia/index.html]].
There is also a FAQ specifically for the Red Hat Linux distribution, at
[[http://www.best.com/~aturner/RedHat-FAQ/faq_index.html]].
Q: Where Is the Linux Stuff on the World Wide Web?|world-wide-web-for-linux-stuff
A: In addition to the Linux Documentation Project Home Page: [[http://tldp.org]],
there are many pages that provide beginning and advanced information about Linux.
These two pages provide a good starting point for general Linux information:
Linux International's Home Page, at [[http://www.li.org]], and the Linux Online's Linux
Home Page at [[http://www.linux.org]].
Both of these pages provide links to other sites, information about general
information, distributions, new software, documentation, and news.
Documentation for kernel developers is on-line: [[http://kernelbook.sourceforge.net]].
The tutorial, <citetitle>Unix is a Four Letter Word...,</citetitle> is
located at [[http://people.msoe.edu/~taylor/4ltrwrd/]].
It is a general introduction to Unix operating systems and is not Linux specific.
Additionally, here is a certainly incomplete list of Web pages devoted to Linux:
*AboutLinux.com: [[http://www.aboutlinux.com]]
*Adventures in Linux Programming: [[http://members.tripod.com/rpragana/]]
*Dave Central Linux Software Archive: [[http://linux.davecentral.com]]
*debianHELP [[http://www.debianhelp.org]]
*Erlug Webzine (Italian): [[http://www.erlug.linux.it]]
*Free Unix Giveaway List: [[http://visar.csustan.edu/giveaway.html]] Lists offers of free Linux CDs. Also available via E-mail: [[mailto:axel@visar.csustan.edu]], with the Subject: "send giveaway_list"
*Information on Linux in corporate environments: [[http://www.smartstocks.com/linux.html]]
*Jeanette Russo's Linux Newbie Information: [[http://www.stormloader.com/jrusso2/index.html]]
*JustLinux.com: [[http://www.justlinux.com]]
*Linux Cartoons: [[http://www.cse.unsw.edu.au/~conradp/linux/cartoons/]]
*LinuxArtist.org: [[http://www.linuxartist.org]]
*Linuxinfor.com - Online Linux Resources: [[http://www.linuxinfor.com]]
*linuXChiX.org: [[http://www.linuxchix.org]]
*LinuxDevices.com: The Embedded Linux Portal: [[http://www.linuxdevices.com]]
*Linux Educational Needs Posting Page: [[http://www.slip.net/~brk/linuxedpp.htm]]
*Linux in Business: Case Studies: [[http://www.bynari.com/collateral/case_studies.html]]
*Linux Hardware Database Laptop Superguide:
[[http://lhd.zdnet.com/db/superguide.php3?catid=18]]
*Linux Inside: [[http://linuxinside.org]]
*Linux Links: [[http://www.linuxlinks.com]]
*Linux Memory Management Home Page: [[http://humbolt.geo.uu.nl/Linux-MM/]]
*Linux Newbie Project: [[http://kusma.hypermart.net/]]
*Linux on the Thinkpad 760ED: [[http://www.e-oasis.com/linux-tp.html]]
*LinuxOrbit: [[http://www.linuxorbit.com]]
*Linux Parallel Port Home Page: [[http://www.torque.net/linux-pp.html]]
*Linux MIDI &amp; Sound Applications: [[http://sound.condorow.net]]
*Linux Start: [[http://www.linuxstart.com]]
*Linux Tips and Tricks Page: [[http://www.patoche.org/LTT/]]
*Linux Today PR: [[http://www.linuxpr.com]]
*Mandrakeuser.Org: [[http://mandrakeuser.org]]
*My Linux Contributions by Richard Gooch: [[http://www.atnf.csiro.au/~rgooch/linux/]]
*Micro Channel Linux Web Page: [[http://www.dgmicro.com/mca/]]
*Parallel port scanners and SANE: [[http://www2.prestel.co.uk/hex/scanners.html]]
*Pascal Central: [[http://www.pascal-central.com]]
*PegaSoft Portal: [[http://www.vaxxine.com/pegasoft/portal/]]
*PocketLinux. [[http://www.pocketlinux.com]]
*Red Hat and ISDN4Linux: [[http://www.webideal.de]]
*SearchLinux: [[http://www.searchlinux.com/]]
*The Free Linux CD Project: [[http://www.freelinuxcd.org]]
*The Site for People Learning Perl: [[http://learn.perl.org]]
*USB Linux Home Page: [[http://peloncho.fis.ucm.es/~inaky/uusbd-www/]]
*VLUG: The Virtual Linux Users Group: [[http://www.vlug.com]]
/*
Searching for <literal>Linux</literal> on Web Search Engines will provide copious
references to Linux Web sites. Try:
*Yahoo! [[http://www.yahoo.com/]]
*Altavista [[http://www.altavista.com/]]
*Google [[http://www.google.com/]]
/*
Google also has a Linux-specific section at [[http://www.google.com/linux/]].
Further information about about Web search
engines is in the <citetitle>Web and Internet Search Engine Faq</citetitle>:
[[http://www.infobasic.com/pagefaq.html]].
Refer also to the answer for: [[link:what-other-faqs]].
Q: What News Groups Are There for Linux?|what-newsgroups
A: <citetitle>Comp.os.linux.announce</citetitle> is the moderated announcements
group. You should read this if you intend to use Linux. It contains
information about software updates, new ports, user group meetings, and
commercial products. It is the '''only''' newsgroup that may
carry commercial postings. Submissions for that group should be e-mailed to
[[mailto:linux-announce@news.ornl.gov]].
<citetitle>Comp.os.linux.announce</citetitle> is archived at:
[[http://www.iki.fi/mjr/linux/cola.html]], and
[[ftp://src.doc.ic.ac.uk/usenet/comp.os.linux.announce/]].
Also worth reading are the following other groups in the
[[news:comp.os.linux]] and
[[news:alt.uu.comp.os.linux]] hierarchies you may find many
common problems too recent for the documentation but are answered in the
newsgroups.
*[[news:alt.uu.comp.os.linux]]
*[[news:alt.uu.comp.os.linux.questions]]
*[[news:alt.os.linux]]
*[[news:alt.os.linux.mandrake]]
*[[news:comp.os.linux.admin]]
*[[news:comp.os.linux.advocacy]]
*[[news:comp.os.linux.alpha]]
*[[news:comp.os.linux.answers]]
*[[news:comp.os.linux.development]]
*[[news:comp.os.linux.development.apps]]
*[[news:comp.os.linux.development.system]]
*[[news:comp.os.linux.embedded]]
*[[news:comp.os.linux.hardware]]
*[[news:comp.os.linux.help]]
*[[news:comp.os.linux.m68k]]
*[[news:comp.os.linux.misc]]
*[[news:comp.os.linux.network]]
*[[news:comp.os.linux.networking]]
*[[news:comp.os.linux.portable]]
*[[news:comp.os.linux.powerpc]]
*[[news:comp.os.linux.questions]]
*[[news:comp.os.linux.redhat]]
*[[news:comp.os.linux.security]]
*[[news:comp.os.linux.setup]]
*[[news:comp.os.linux.test]]
*[[news:comp.os.linux.x]]
*[[news:comp.os.linux.x.video]]
/*
Remember that Linux is POSIX compatible, and most all of the material in the
[[news:comp.unix]] and
[[news:comp.windows.x]] groups will be relevant. Apart from
hardware considerations, and some obscure or very technical low-level issues,
you'll find that these groups are good places to start.
Information about e-mail clients (MUA's), mail transfer agents (MTA's), and
other related software are in the <literal>comp.mail.*</literal> groups,
especially:
*[[news:comp.mail.misc]]
*[[news:comp.mail.pine]]
*[[news:comp.mail.sendmail]]
/*
Questions and information about News reading software are in:
*[[news:news.software.readers]].
/*
Please read [[link:still-havent-answered]] before posting.
Cross posting between
different [[news:comp.os.linux]] groups is rarely a good idea.
There may well be Linux groups local to your institution or areacheck there
first.
See also [[link:i-dont-have-usenet-access]].
Other regional and local newsgroups also existyou may find the traffic more
manageable there:
*[[news:fr.comp.os.linux]] (France).
*[[news:de.comp.os.linux]] (Germany).
*[[news:aus.computers.linux]] (Australia).
*[[news:hr.comp.linux]] (Croatia).
*[[news:it.comp.linux]] (Italy).
/*
A search of [[http://groups.google.com/]] can provide an
up-to-date list of News groups.
[Axel Boldt, Robert Kiesling]
Q: What Other FAQ's and Documentation Are There for Linux?|what-other-faqs
A: There are a number of special interest FAQ's on different subjects related to
system administration and use, and also on miscellaneous topics like Flying
Saucer Attacks (the music) and support for recovering sysadmins.
The official Usenet FAQ archives are: [[ftp://rtfm.mit.edu/pub/usenet/]].
The <citetitle>Internet FAQ Consortium</citetitle> provides a searchable
archive at: [[http://www.faqs.org/]]. The site also maintains a
current archive of Internet Request For Comment (RFC), Best Current Practices
(BCP), and For Your Information (FYI) documents.
Here are some FAQ's and documents that might be especially useful, and their
network addresses:
*A FAQ for new users: [[http://homes.arealcity.com/swietanowski/LinuxFAQ/]]
*A Linux FAQ in Spanish is available at: [[http://www.abierta.org/faq.htm]]
Un FAQ (preguntas mas frecuentes) en Espa<70>ol se halla disponible en [[http://www.abierta.org/faq.htm]]
*AfterStep FAQ: [[http://www.linuxinfor.com/en/astepfaq/AfterStep-FAQ.html]]
*BASH Frequently Asked Questions: [[ftp://ftp.cwru.edu/pug/bash/FAQ/]]
*<literal>de.comp.os.unix.linux.infos - FAQ</literal>: [[http://www.dcoul.de/]]
*Frequently Asked Questions about Open Source: [[http://www.opensource.org/faq.html]]
*Ftape-FAQ: [[http://www.linuxinfor.com/en/ftapefaq/Ftape-FAQ.html]]
*GNU Emacs: [[http://www.lerner.co.il/emacs/faq-body.shtml]]
*GNU Linux in Science and Engineering: [[http://www.comsoc.org/vancouver/scieng.html]]
*GNU Troff ('''groff''') Info: [[http://www.cs.pdx.edu/~trent/gnu/groff/]]
*Gnus 5.x: [[http://www.ccs.neu.edu/software/contrib/gnus/]]
*KDE FAQ: [[http://www.kde.org/faq.html]]
*GNU General Public License FAQ: [[http://www.gnu.org/copyleft/gpl-faq.html]]
*Linux PPP FAQ: [[http://www.linuxinfor.com/en/pppfaq/PPP-FAQ.html]]
*Linux-Raid FAQ: [[http://www.linuxinfor.com/en/raidfaq/index.html]]
*List of Periodic Information Postings: [[ftp://rtfm.mit.edu/pub/usenet/news.answers/periodic-postings/]]
*News.newusers.announce FAQ [[http://web.presby.edu/~nnqadmin/nan/]]
*Online Linux Resources: [[http://www.linuxinfor.com/en/docfaq.htm]]
*O'Reilly &amp; Associates Openbook Project: [[http://www.oreilly.com/openbook/]]
*<application>Sendmail</application>: [[http://www.sendmail.org/faq/]]
*<citetitle>Sendmail: Installation and Operation Guide:</citetitle> Formatted
and '''me''' source versions are in the
<literal>doc/</literal> subdirectory of <application>Sendmail</application>
source code distributions. [[http://www.sendmail.org/]]
*Technical FAQ for Linux Users: [[http://www-106.ibm.com/developerworks/library/l-faq/?n-l-7261]]
*Web Internet Search Engine: [[http://www.infobasic.com/pagefaq.html]]
*Wu-ftpd: [[http://www.wu-ftpd.org/man/]] (really a collection of man pages), with
HOWTO's at: [[http://www.wu-ftpd.org/HOWTO/]]
*XTERM Frequently Asked Questions. [[http://dickey.his.com/xterm/xterm.faq.html]]
/*
Q: How To Get Information without Usenet Access|i-dont-have-usenet-access
A: A digest of
comp.os.linux.announce is available by mailing the word "subscribe" (without
the quotes) as the body of a message to
[[mailto:linux-announce-REQUEST@news-digests.mit.edu]].
Subscribing to this list is a good idea, as it carries important information
and documentation about Linux.
Please remember to use the *-request addresses for your subscribe and unsubscribe messages; mail to the
other address is posted to the news group.
Q: What Mailing Lists Are There?|what-mailing-lists-are-there
A: The Linux developers now mainly use the
Majordomo server at [[mailto:majordomo@vger.redhat.com]]. Send a message with the
word "lists" (without the quotes) in the body to get a list of lists there.
Add a line with the word, "help," to get the standard Majordomo help file
that lists instructions for subscribing and unsubscribing to the lists.
Currently, the kernel list is archived at:
[[http://www.uwsg.indiana.edu/hypermail/linux/kernel/]],
and [[http://www.lib.uaa.alaska.edu/linux-kernel/archive/]]
Please do not post off-topic material to the mailing
lists. Most of them are used by Linux developers to talk about technical
issues and future developments. They are not intended for new users'
questions, advertisements, or public postings that are not directly related
to the mailing list's subject matter.
<citetitle>Comp.os.linux.announce</citetitle> is the place for all public
announcements. This is a common Internet policy. If you don't observe this
guideline, there's a good chance that you'll be flamed.
There is a linux-newbie list where, "no question is too stupid." Unfortunately, it
seems that few experienced users read that list, and it has very low volume.
There are numerous Linux related mailing lists at [[http://www.onelist.com/]].
Go to the categories page and choose "Linux." There are also mailing list subscription links at:
[[http://oslab.snu.ac.kr/~djshin/linux/mail-list/]]
The <citetitle>Mailing Lists Available in Usenet</citetitle> page is: [[http://paml.net/]].
The list information is also on: [[ftp://rtfm.mit.edu/]], and is posted to the groups:
<literal>news.announce.newgroups</literal>, <literal>news.lists</literal>,
and <literal>news.groups</literal>, among others.
Q: Are the News Groups Archived Anywhere?|are-the-newsgroups-archived-anywhere
A: The Usenet Linux news groups are archived at [[http://groups.google.com/]].
[[ftp://metalab.unc.edu/pub/Linux/docs/linux-announce.archive]] contains archives of
[[news:comp.os.linux.announce]]. These are mirrored from
[[ftp://src.doc.ic.ac.uk/usenet/]], which also
archives [[news:comp.os.linux]],
[[news:comp.os.linux.development.apps]], and
[[news:comp.os.linux.development.system]].
Q: Where Are Linux Legal Issues Discussed?|where-are-linux-legal-issues-discussed
A: On the linux-legal mailing list, of course. You can subscribe to it, as with many of the other
Linux related lists, by sending a message with the word "help" in the body of
the message to [[mailto:majordomo@vger.redhat.com]].
Q: Where is Information about Unmaintained Free Software Projects?|free-software-projects
A: There are Web pages at: [[http://unmaintained.sourceforge.net]], and:
[[http://www.orphansource.org/]].
Please try to contact the original author(s) via e-mail, or the person who
listed the software as unmaintained, before even thinking to place a license
on the package.
Q: What Online/Free Periodicals Exist for Linux?|online-free-periodicals
A: There are a number of recent
additions to the list of periodicals devoted to Linux and free software:
*<citetitle>geek news</citetitle>. [[http://geeknews.cjb.net/]]. Headlines for articles
about Linux, like the [[news:comp.os.linux.announce]] and
Techweb postings, and general interest, like Associated Press stories.
*<citetitle>Linux Gazette</citetitle>. [[http://www.linuxgazette.com/]].
This is the longest-running of the on-line periodicals, and the only one that publishes
source code.
*<citetitle>LinuxToday</citetitle>. [[http://www.linuxtoday.com]]. News and opinion
related to the Linux community, updated daily.
*<citetitle>Linux Weekly News</citetitle>. [[http://lwn.net]]. News about the Linux community,
updated weekly.
*<citetitle>Slashdot</citetitle>. [[http://www.slashdot.org]]. News about the free
software community and culture.
*<citetitle>Freshmeat</citetitle>. [[http://www.freshmeat.net/]]. Notices of new and
updated software for Linux and other free OS's.
/*
Please send additions to this list to the FAQ
maintainer, see [[link:feedback]].
Q: Where Can I To Find Information About Security Related Issues?|about-security-related-issues
A: There's a page of Linux related security information at: [[http://www.linuxsecurity.com/]].
Another site is: [[http://www.rootshell.com/]], which has information about
Internet security and privacy issues.
For information about the <citetitle>Weekly Linux Security Digest</citetitle>
email newsletter and numerous security related databases, look at [[http://securityportal.com/]].
=How To Get Further Assistance|further-assistance=
==If this Document Still Hasn't Answered Your Question....|still-havent-answered==
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
David Merrill. See [[link:feedback]].
Read the appropriate Linux Documentation Project books.
Refer to [[link:howtos-and-other-documentation]].
If you're a Unix or Linux newbie, read the FAQ for
[[news:comp.unix.questions]],
[[news:news.announces.newusers]], and those for any of
the other [[news: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 FAQ's, like all
FAQ's, be found on [[ftp://rtfm.mit.edu/pub/usenet/]] (the
[[mailto:mail-server@rtfm.mit.edu]] can send
you these files, if you don't have FTP access). There are mirrors of
<literal>rtfm</literal>'s FAQ archives on various sites. Check the
Introduction to *.answers posting, or look in
<filename>news-answers/introduction</filename> 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 <literal>man man</literal> if
you don't know about manual pages. Also try
<literal>man -k subject</literal> and <literal>apropos subject</literal>. They
often list useful and relevant, but not very obvious, manual pages.
Check the Info documentation (type
<keycombo><keycap>F1</keycap><keycap>i</keycap></keycombo>,
i.e. the <keycap>F1</keycap> function key 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
ityou probably made a mistake the first time.
Read [[news:comp.os.linux.announce]]. It often
contains very important information for all Linux users.
General X Window System questions belong in
[[news:comp.windows.x.i386unix]],
not in [[news: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 [[news:comp.os.linux]]
newsgroup. Make sure you
read the next question first. "( What to put in a request for
help. )"
==What to Put in a Request for Help|what-in-request-help==
Please read the following advice carefully about how to write your
posting or E-mail. 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
E-mail 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
<literal>--version</literal> 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
<literal>uname -a</literal>, and
the shared library version by typing
<literal>ls -l /lib/libc*</literal>.
*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 &mdash; 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.
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
<literal>Followup-To: poster</literal>.
Then, actually post the summary in a few days or a week or so. Don't
just concatenate the replies you received, summarize them. Putting the word
"SUMMARY" in your summary's Subject line is also a good idea. Consider
submitting the summary to [[news: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'sthis may make people less likely to skip your
posting.
Remember that you should not post E-mail sent to you personally without
the sender's permission.
==How To Email Someone about Your Problem|mail-someone-about-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 likely asking for help from unpaid volunteers, so you have no
right to expect an answer.
<appendix id='fdl'><title id='fdl-title'>GNU Free Documentation License</title>
<literallayout>
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
</literallayout>
=0. PREAMBLE=
The purpose of this License is to make a manual, textbook, or other written
document "free" in the sense of freedom: to assure everyone the effective
freedom to copy and redistribute it, with or without modifying it, either
commercially or noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not being
considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative works of
the document must themselves be free in the same sense. It complements the
GNU General Public License, which is a copyleft license designed for free
software.
We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free program
should come with manuals providing the same freedoms that the software does.
But this License is not limited to software manuals; it can be used for any
textual work, regardless of subject matter or whether it is published as a
printed book. We recommend this License principally for works whose purpose
is instruction or reference.
=1. APPLICABILITY AND DEFINITIONS=
This License applies to any manual or other work that contains a notice
placed by the copyright holder saying it can be distributed under the terms
of this License. The "Document", below, refers to any such manual or work.
Any member of the public is a licensee, and is addressed as "you".
A "Modified Version" of the Document means any work containing the Document
or a portion of it, either copied verbatim, or with modifications and/or
translated into another language.
A "Secondary Section" is a named appendix or a front-matter section of the
Document that deals exclusively with the relationship of the publishers or
authors of the Document to the Document's overall subject (or to related
matters) and contains nothing that could fall directly within that overall
subject. (For example, if the Document is in part a textbook of mathematics,
a Secondary Section may not explain any mathematics.) The relationship could
be a matter of historical connection with the subject or with related
matters, or of legal, commercial, philosophical, ethical or political
position regarding them.
The "Invariant Sections" are certain Secondary Sections whose titles are
designated, as being those of Invariant Sections, in the notice that says
that the Document is released under this License.
The "Cover Texts" are certain short passages of text that are listed, as
Front-Cover Texts or Back-Cover Texts, in the notice that says that the
Document is released under this License.
A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the general
public, whose contents can be viewed and edited directly and
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or for
automatic translation to a variety of formats suitable for input to text
formatters. A copy made in an otherwise Transparent file format whose markup
has been designed to thwart or discourage subsequent modification by readers
is not Transparent. A copy that is not "Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain ASCII
without markup, Texinfo input format, LaTeX input format, SGML or XML using a
publicly available DTD, and standard-conforming simple HTML designed for
human modification. Opaque formats include PostScript, PDF, proprietary
formats that can be read and edited only by proprietary word processors, SGML
or XML for which the DTD and/or processing tools are not generally available,
and the machine-generated HTML produced by some word processors for output
purposes only.
The "Title Page" means, for a printed book, the title page itself, plus
such following pages as are needed to hold, legibly, the material this
License requires to appear in the title page. For works in formats which do
not have any title page as such, "Title Page" means the text near the most
prominent appearance of the work's title, preceding the beginning of the body
of the text.
=2. VERBATIM COPYING=
You may copy and distribute the Document in any medium, either commercially
or noncommercially, provided that this License, the copyright notices, and
the license notice saying this License applies to the Document are reproduced
in all copies, and that you add no other conditions whatsoever to those of
this License. You may not use technical measures to obstruct or control the
reading or further copying of the copies you make or distribute. However, you
may accept compensation in exchange for copies. If you distribute a large
enough number of copies you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and you
may publicly display copies.
=3. COPYING IN QUANTITY=
If you publish printed copies of the Document numbering more than 100, and
the Document's license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover Texts:
Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover.
Both covers must also clearly and legibly identify you as the publisher of
these copies. The front cover must present the full title with all words of
the title equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as long as
they preserve the title of the Document and satisfy these conditions, can be
treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit legibly,
you should put the first ones listed (as many as fit reasonably) on the
actual cover, and continue the rest onto adjacent pages.
If you publish or distribute Opaque copies of the Document numbering more
than 100, you must either include a machine-readable Transparent copy along
with each Opaque copy, or state in or with each Opaque copy a
publicly-accessible computer-network location containing a complete
Transparent copy of the Document, free of added material, which the general
network-using public has access to download anonymously at no charge using
public-standard network protocols. If you use the latter option, you must
take reasonably prudent steps, when you begin distribution of Opaque copies
in quantity, to ensure that this Transparent copy will remain thus accessible
at the stated location until at least one year after the last time you
distribute an Opaque copy (directly or through your agents or retailers) of
that edition to the public.
It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give them
a chance to provide you with an updated version of the Document.
=4. MODIFICATIONS=
You may copy and distribute a Modified Version of the Document under the
conditions of sections 2 and 3 above, provided that you release the Modified
Version under precisely this License, with the Modified Version filling the
role of the Document, thus licensing distribution and modification of the
Modified Version to whoever possesses a copy of it. In addition, you must do
these things in the Modified Version:
* A. Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions (which
should, if there were any, be listed in the History section of the
Document). You may use the same title as a previous version if the
original publisher of that version gives permission.
* B. List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified Version,
together with at least five of the principal authors of the Document (all
of its principal authors, if it has less than five).
* C. State on the Title Page the name of the publisher of the Modified
Version, as the publisher.
* D. Preserve all the copyright notices of the Document.
* E. Add an appropriate copyright notice for your modifications adjacent to
the other copyright notices.
* F. Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the terms
of this License, in the form shown in the Addendum below.
* G. Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document's license notice.
* H. Include an unaltered copy of this License.
* I. Preserve the section entitled "History", and its title, and add to it
an item stating at least the title, year, new authors, and publisher of
the Modified Version as given on the Title Page. If there is no section
entitled "History" in the Document, create one stating the title, year,
authors, and publisher of the Document as given on its Title Page, then
add an item describing the Modified Version as stated in the previous
sentence.
* J. Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and likewise the
network locations given in the Document for previous versions it was
based on. These may be placed in the "History" section. You may omit a
network location for a work that was published at least four years before
the Document itself, or if the original publisher of the version it
refers to gives permission.
* K. In any section entitled "Acknowledgements" or "Dedications", preserve
the section's title, and preserve in the section all the substance and
tone of each of the contributor acknowledgements and/or dedications given
therein.
* L. Preserve all the Invariant Sections of the Document, unaltered in
their text and in their titles. Section numbers or the equivalent are not
considered part of the section titles.
* M. Delete any section entitled "Endorsements". Such a section may not be
included in the Modified Version.
* N. Do not retitle any existing section as "Endorsements" or to conflict
in title with any Invariant Section.
If the Modified Version includes new front-matter sections or appendices
that qualify as Secondary Sections and contain no material copied from the
Document, you may at your option designate some or all of these sections as
invariant. To do this, add their titles to the list of Invariant Sections in
the Modified Version's license notice. These titles must be distinct from any
other section titles.
You may add a section entitled "Endorsements", provided it contains nothing
but endorsements of your Modified Version by various parties--for example,
statements of peer review or that the text has been approved by an
organization as the authoritative definition of a standard.
You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list of
Cover Texts in the Modified Version. Only one passage of Front-Cover Text and
one of Back-Cover Text may be added by (or through arrangements made by) any
one entity. If the Document already includes a cover text for the same cover,
previously added by you or by arrangement made by the same entity you are
acting on behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added the old
one.
The author(s) and publisher(s) of the Document do not by this License give
permission to use their names for publicity for or to assert or imply
endorsement of any Modified Version .
=5. COMBINING DOCUMENTS=
You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified versions,
provided that you include in the combination all of the Invariant Sections of
all of the original documents, unmodified, and list them all as Invariant
Sections of your combined work in its license notice.
The combined work need only contain one copy of this License, and multiple
identical Invariant Sections may be replaced with a single copy. If there are
multiple Invariant Sections with the same name but different contents, make
the title of each such section unique by adding at the end of it, in
parentheses, the name of the original author or publisher of that section if
known, or else a unique number. Make the same adjustment to the section
titles in the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections entitled "History" in the
various original documents, forming one section entitled "History"; likewise
combine any sections entitled "Acknowledgements", and any sections entitled
"Dedications". You must delete all sections entitled "Endorsements."
=6. COLLECTIONS OF DOCUMENTS=
You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in the
collection, provided that you follow the rules of this License for verbatim
copying of each of the documents in all other respects.
You may extract a single document from such a collection, and dispbibute it
individually under this License, provided you insert a copy of this License
into the extracted document, and follow this License in all other respects
regarding verbatim copying of that document.
=7. AGGREGATION WITH INDEPENDENT WORKS=
A compilation of the Document or its derivatives with other separate and
independent documents or works, in or on a volume of a storage or
distribution medium, does not as a whole count as a Modified Version of the
Document, provided no compilation copyright is claimed for the compilation.
Such a compilation is called an "aggregate", and this License does not apply
to the other self-contained works thus compiled with the Document , on
account of their being thus compiled, if they are not themselves derivative
works of the Document. If the Cover Text requirement of section 3 is
applicable to these copies of the Document, then if the Document is less than
one quarter of the entire aggregate, the Document's Cover Texts may be placed
on covers that surround only the Document within the aggregate. Otherwise
they must appear on covers around the whole aggregate.
=8. TRANSLATION=
Translation is considered a kind of modification, so you may distribute
translations of the Document under the terms of section 4. Replacing
Invariant Sections with translations requires special permission from their
copyright holders, but you may include translations of some or all Invariant
Sections in addition to the original versions of these Invariant Sections.
You may include a translation of this License provided that you also include
the original English version of this License. In case of a disagreement
between the translation and the original English version of this License, the
original English version will prevail.
=9. TERMINATION=
You may not copy, modify, sublicense, or distribute the Document except as
expressly provided for under this License. Any other attempt to copy, modify,
sublicense or distribute the Document is void, and will automatically
terminate your rights under this License. However, parties who have received
copies, or rights, from you under this License will not have their licenses
terminated so long as such parties remain in full compliance.
=10. FUTURE REVISIONS OF THIS LICENSE=
The Free Software Foundation may publish new, revised versions of the GNU
Free Documentation License from time to time. Such new versions will be
similar in spirit to the present version, but may differ in detail to address
new problems or concerns. See [http://www.gnu.org/copyleft] http://
www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If
the Document specifies that a particular numbered version of this License "or
any later version" applies to it, you have the option of following the terms
and conditions either of that specified version or of any later version that
has been published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may choose
any version ever published (not as a draft) by the Free Software Foundation.
=Addendum=
To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license notices
just after the title page:
<blockquote>
Copyright &copy; YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or any
later version published by the Free Software Foundation; with the
Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts
being LIST, and with the Back-Cover Texts being LIST. A copy of the
license is included in the section entitled "GNU Free Documentation
License".
</blockquote>
If you have no Invariant Sections, write "with no Invariant Sections"
instead of saying which ones are invariant. If you have no Front-Cover Texts,
write "no Front-Cover Texts" instead of "Front-Cover Texts being LIST";
likewise for Back-Cover Texts.
If your document contains nontrivial examples of program code, we recommend
releasing these examples in parallel under your choice of free software
license, such as the GNU General Public License, to permit their use in free
software.
</appendix>
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