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diff --git a/book.html b/book.html new file mode 100644 index 0000000..2b91276 --- /dev/null +++ b/book.html @@ -0,0 +1,2560 @@ +<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>The Slack Book</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book" title="The Slack Book"><div class="titlepage"><div><div><h1 class="title"><a name="id54440"></a>The Slack Book</h1></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="preface"><a href="#id335177">Foreward</a></span></dt><dd><dl><dt><span class="section"><a href="#id337010">Intended Audience</a></span></dt><dt><span class="section"><a href="#id316534">Why A New Slackware Book?</a></span></dt><dt><span class="section"><a href="#id330458">Conventions Used in this Book</a></span></dt><dt><span class="section"><a href="#id335728">Acknowledgements</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id317008">1. Introduction to Slackware</a></span></dt><dd><dl><dt><span class="section"><a href="#id311524">Why Use Slackware?</a></span></dt><dt><span class="section"><a href="#id311677">Differences with other Linux Distributions</a></span></dt><dt><span class="section"><a href="#id341400">Licensing</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id297229">2. Installation</a></span></dt><dd><dl><dt><span class="section"><a href="#id352319">Booting the Installer</a></span></dt><dt><span class="section"><a href="#id330240">Partitioning</a></span></dt><dt><span class="section"><a href="#id326672">The <span class="application">setup</span> Program</a></span></dt><dd><dl><dt><span class="section"><a href="#id326687">Help</a></span></dt><dt><span class="section"><a href="#id326694">Keymap</a></span></dt><dt><span class="section"><a href="#id326702">Addswap</a></span></dt><dt><span class="section"><a href="#id326709">Target</a></span></dt><dt><span class="section"><a href="#id326717">Source</a></span></dt><dt><span class="section"><a href="#id326724">Select</a></span></dt><dt><span class="section"><a href="#id326732">Install</a></span></dt><dt><span class="section"><a href="#id326739">Configure</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#id297222">3. Booting</a></span></dt><dd><dl><dt><span class="section"><a href="#id357891"><span class="application">mkinitrd</span></a></span></dt><dt><span class="section"><a href="#id326605">LILO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id288954">4. Basic Shell Commands</a></span></dt><dd><dl><dt><span class="section"><a href="#id326497">System Documentation</a></span></dt><dt><span class="section"><a href="#id330395">Dealing with Files and Directories</a></span></dt><dd><dl><dt><span class="section"><a href="#id330401"><span class="application">Listing Files and Directory Contents</span></a></span></dt><dt><span class="section"><a href="#id351195">Moving Around the Filesystem</a></span></dt><dt><span class="section"><a href="#id354028">File and Directory Creation and Deletion</a></span></dt></dl></dd><dt><span class="section"><a href="#id354344">Reading Documents</a></span></dt><dt><span class="section"><a href="#id354528">Linking</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id336592">5. The Bourne Again Shell</a></span></dt><dd><dl><dt><span class="section"><a href="#id282479">What Is A Shell?</a></span></dt><dt><span class="section"><a href="#id314358">Environment Variables</a></span></dt><dt><span class="section"><a href="#id313824">Wildcards</a></span></dt><dt><span class="section"><a href="#id335881">Tab Completion</a></span></dt><dt><span class="section"><a href="#id354670">Input and Output Redirection</a></span></dt><dt><span class="section"><a href="#id354937">Terminals</a></span></dt><dt><span class="section"><a href="#id355019">Customization</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id325945">6. The X Window System</a></span></dt><dd><dl><dt><span class="section"><a href="#id358884">What Is (And Isn't) X</a></span></dt><dt><span class="section"><a href="#id320754">Configuring the X Server</a></span></dt><dt><span class="section"><a href="#id314642">Choosing a Window Manager</a></span></dt><dt><span class="section"><a href="#id351028">Setting Up A Graphical Login</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id292994">7. Printing</a></span></dt><dd><dl><dt><span class="section"><a href="#id337782">Choosing A Printer</a></span></dt><dt><span class="section"><a href="#id357050">Setting Up a Printer in CUPS</a></span></dt><dt><span class="section"><a href="#id322037">Commandline Printing Tools</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id337784">8. Users and Groups</a></span></dt><dd><dl><dt><span class="section"><a href="#id359209">What Are Users and Groups?</a></span></dt><dt><span class="section"><a href="#id341153">Managing Users and Groups</a></span></dt><dt><span class="section"><a href="#id359270">Other User and Group Tools</a></span></dt><dt><span class="section"><a href="#id321249">Managing Users and Groups Manually</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id290832">9. Filesystem Permissions</a></span></dt><dd><dl><dt><span class="section"><a href="#id312644">Permissions Overview</a></span></dt><dt><span class="section"><a href="#id336783"><span class="application">chmod</span>, +<span class="application">chown</span>, and +<span class="application">chgrp</span></a></span></dt><dt><span class="section"><a href="#id342316">SUID, SGID, and the "Sticky" Bit</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id283108">10. Working with Filesystems</a></span></dt><dd><dl><dt><span class="section"><a href="#id325517">The Filesystem Hierarchy</a></span></dt><dt><span class="section"><a href="#id318597">Local Filesystem Types</a></span></dt><dd><dl><dt><span class="section"><a href="#id318610">ext2</a></span></dt><dt><span class="section"><a href="#id318624">ext3</a></span></dt><dt><span class="section"><a href="#id318642">reiserfs</a></span></dt><dt><span class="section"><a href="#id318656">XFS</a></span></dt><dt><span class="section"><a href="#id318671">JFS</a></span></dt><dt><span class="section"><a href="#id318685">iso9660</a></span></dt><dt><span class="section"><a href="#id318711">vfat</a></span></dt><dt><span class="section"><a href="#id355976">swap</a></span></dt></dl></dd><dt><span class="section"><a href="#id355992">Using <span class="application">mount</span></a></span></dt><dt><span class="section"><a href="#id360747">Network Filesystems</a></span></dt><dd><dl><dt><span class="section"><a href="#id360758">NFS</a></span></dt><dt><span class="section"><a href="#id360899">SMB</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#id282063">11. <span class="application">vi</span></a></span></dt><dd><dl><dt><span class="section"><a href="#id352102">What is <span class="application">vi</span>?</a></span></dt><dt><span class="section"><a href="#id314220">The Different Modes of <span class="application">vi</span></a></span></dt><dt><span class="section"><a href="#id317601">Opening, Saving, and Quitting</a></span></dt><dt><span class="section"><a href="#id320876">Moving Around</a></span></dt><dt><span class="section"><a href="#id342976">Editing A Document</a></span></dt><dt><span class="section"><a href="#id343009"><span class="application">vi</span> Cheat Sheet</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id342041">12. Emacs</a></span></dt><dd><dl><dt><span class="section"><a href="#id317667">No Idea</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id289613">13. Networking</a></span></dt><dd><dl><dt><span class="section"><a href="#id328201"><span class="application">netconfig</span></a></span></dt><dt><span class="section"><a href="#id310624">Manual Configuration</a></span></dt><dt><span class="section"><a href="#id319849">Automatic Configuration with rc.inet1.conf</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id329344">14. Wireless Networking</a></span></dt><dd><dl><dt><span class="section"><a href="#id326142"><span class="application">iwconfig</span></a></span></dt><dt><span class="section"><a href="#id359178">Wired Equivilant Protection (or Lack Thereof)</a></span></dt><dt><span class="section"><a href="#id334833">WPA</a></span></dt><dt><span class="section"><a href="#id334290">rc.inet1.conf revisited</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id284408">15. Basic Networking Commands</a></span></dt><dd><dl><dt><span class="section"><a href="#id348624">Network Diagnostic Tools</a></span></dt><dt><span class="section"><a href="#id333340">Web Browsers</a></span></dt><dt><span class="section"><a href="#id351638">FTP Clients</a></span></dt><dt><span class="section"><a href="#id317884">NNTP Clients</a></span></dt><dt><span class="section"><a href="#id341101">Remote Access</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id320396">16. Package Management</a></span></dt><dd><dl><dt><span class="section"><a href="#id358328"><span class="application">pkgtool</span></a></span></dt><dt><span class="section"><a href="#id352958">Installing, Removing, and Upgrading Packages</a></span></dt><dt><span class="section"><a href="#id341343"><span class="application">pkgtool</span></a></span></dt></dl></dd><dt><span class="chapter"><a href="#id292742">17. Keeping Track of Updates</a></span></dt><dd><dl><dt><span class="section"><a href="#id314047">The -stable Branch</a></span></dt><dt><span class="section"><a href="#id324804">Upgrading Slackware Versions</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id328461">18. The Linux Kernel</a></span></dt><dd><dl><dt><span class="section"><a href="#id322300">What Does the Kernel Do?</a></span></dt><dt><span class="section"><a href="#id325022">Working with Modules</a></span></dt><dt><span class="section"><a href="#id353213">Compiling A Kernel and Why to do So</a></span></dt></dl></dd></dl></div><div class="list-of-tables"><p><b>List of Tables</b></p><dl><dt>4.1. <a href="#id333534">Man Page Sections</a></dt><dt>9.1. <a href="#id337693">Permissions of /bin/ls</a></dt><dt>9.2. <a href="#id330724">Octal Permissions</a></dt><dt>9.3. <a href="#id342090">Alphabetic Permissions</a></dt><dt>9.4. <a href="#id342158">Alphabetic Users and Groups</a></dt><dt>9.5. <a href="#id342457">SUID, SGID, and "Sticky" Permissions</a></dt><dt>10.1. <a href="#id336627">Filesystem Layout</a></dt><dt>10.2. <a href="#id356105">Common mount options</a></dt><dt>11.1. <a href="#id348996">vi cursor movement</a></dt><dt>11.2. <a href="#id343030">vi Cheat Sheet</a></dt></dl></div><div class="preface" title="Foreward"><div class="titlepage"><div><div><h2 class="title"><a name="id335177"></a>Foreward</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id337010">Intended Audience</a></span></dt><dt><span class="section"><a href="#id316534">Why A New Slackware Book?</a></span></dt><dt><span class="section"><a href="#id330458">Conventions Used in this Book</a></span></dt><dt><span class="section"><a href="#id335728">Acknowledgements</a></span></dt></dl></div><div class="section" title="Intended Audience"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id337010"></a>Intended Audience</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Why A New Slackware Book?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id316534"></a>Why A New Slackware Book?</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Conventions Used in this Book"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id330458"></a>Conventions Used in this Book</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Acknowledgements"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id335728"></a>Acknowledgements</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div></div><div class="chapter" title="Chapter 1. Introduction to Slackware"><div class="titlepage"><div><div><h2 class="title"><a name="id317008"></a>Chapter 1. Introduction to Slackware</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id311524">Why Use Slackware?</a></span></dt><dt><span class="section"><a href="#id311677">Differences with other Linux Distributions</a></span></dt><dt><span class="section"><a href="#id341400">Licensing</a></span></dt></dl></div><div class="section" title="Why Use Slackware?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id311524"></a>Why Use Slackware?</h2></div></div></div><p> +Slackware has a long tradition of excellence. Started in 1992 and +first released in 1993, Slackware is the oldest surviving commercial +Linux distribution. Slackware's focus on making a clean, simple Linux +distribution that is as UNIX-like as possible makes it a natural choice +for those people who really want to learn about Linux and other +UNIX-like operating systems. Slackware's simplicity makes it ideal for +those users who want to create their own custom systems. And of course, +Slackware is great in its own right as a desktop, workstation, or server. +</p></div><div class="section" title="Differences with other Linux Distributions"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id311677"></a>Differences with other Linux Distributions</h2></div></div></div><p> +There are a great number of differences between Slackware and other +main-stream distributions such as Red Hat, Debian, and Ubuntu. Perhaps +the greatest difference is the lack of "hand-holding" that Slackware +will do for the administrator. Many of these other distributions ship +with graphical configuration tools for all manner of services. In many +cases these configuration tools are the preferred method of setting up +applications on these systems and will over-write any changes you make +to the config files via other means. These tools often make it easy +(or at least possible) for a rookie with no in-depth understanding of +his system to setup basic services; however, they also make it +difficult to do anything too out of the ordinary. In contrast, +Slackware expects you, the system administrator, to do these tasks on +your own. Slackware provides no general purpose setup tools beyond +those included with the source code published by up-stream developers. +This means there is often a somewhat steeper learning curve associated +with Slackware, even for those users familiar with other Linux +distributions, but also makes it much easier to do whatever you want +with your operating system. +</p><p> +Also, you may hear users of other distributions say that Slackware has +no package management system. This is completely and obviously false. +Slackware has always had package management (see Chapter 16 for more +information). What it does not have is automatic dependency +resolution. Rather, Slackware's package tools trade dependency +management for simplicity, ease-of-use, and reliability. +</p></div><div class="section" title="Licensing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id341400"></a>Licensing</h2></div></div></div><p> +Each piece of Slackware (indeed of all Linux distributions) is +developed by different people or teams of people, and each group has +their own ideas about what it means to be "free". Because of this +there are literally dozens and dozens of different licenses granting +you different permissions regarding their use or distribution. +</p><p> +Perhaps the most popular license in use within the Free Software +community is the GNU General Public License. +The GPL was created by the Free Software +Foundation which actively works to create and distribute software that +contains the basic freedoms they fill are basic rights. Indeed, this +is the very group that coined the term "Free Software". The GPL +imposes no restrictions on the use of software. In fact, you don't +even have to accept the terms of the license in order to use the +software, but you are not allowed to distribute the software or your +changes to it without abiding by the terms of the license agreement. A +great many software projects shipped with Slackware from the Linux +kernel itself to the Samba project are released under the terms of the +GPL. +</p><p> +Another very common license is the BSD license, which is arguably "more +free" than the GPL, but imposes no restrictions on derivative works. +The BSD license simply requires that the copyright remain intact, along +with a simple disclaimer. Many of the utilities specific to Slackware +are licensed with a BSD-style license. +</p></div></div><div class="chapter" title="Chapter 2. Installation"><div class="titlepage"><div><div><h2 class="title"><a name="id297229"></a>Chapter 2. Installation</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id352319">Booting the Installer</a></span></dt><dt><span class="section"><a href="#id330240">Partitioning</a></span></dt><dt><span class="section"><a href="#id326672">The <span class="application">setup</span> Program</a></span></dt><dd><dl><dt><span class="section"><a href="#id326687">Help</a></span></dt><dt><span class="section"><a href="#id326694">Keymap</a></span></dt><dt><span class="section"><a href="#id326702">Addswap</a></span></dt><dt><span class="section"><a href="#id326709">Target</a></span></dt><dt><span class="section"><a href="#id326717">Source</a></span></dt><dt><span class="section"><a href="#id326724">Select</a></span></dt><dt><span class="section"><a href="#id326732">Install</a></span></dt><dt><span class="section"><a href="#id326739">Configure</a></span></dt></dl></dd></dl></div><p> +Slackware's installation is a bit more simplistic than many other Linux +distributions use, and is very reminiscent of installing one of the +varieties of BSD operating systems. If you're familiar with those, you +should feel right at home. If you've never installed Slackware or used +a distribution that makes use of a non-graphical installer, you may +feel a bit overwhelmed. Don't panic. The installation is very easy +once you understand it, and works on just about any x86 platform. +</p><p> +The latest versions of Slackware Linux are distributed on DVD or CD +media, but Slackware can be installed in a variety of other ways. This +book will only focus on the most common way: installing via optical +media. In order to install Slackware, you'll need at least an Intel +486 or equivilant CPU, but we recommend you obtain a 586 or better CPU +if at all possible. Slackware can be pared down to run on as little as +32 MB of RAM (or even less), but with the size of the 2.6 kernel and +user-space applications, you will find yourself having a much easier +time if you have a minimum of 64 MB of RAM. If you wish to use +anything older than these, you might want to obtain an older copy of +Slackware which will perform better with fewer CPU Megahertz and less +RAM. +</p><div class="section" title="Booting the Installer"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id352319"></a>Booting the Installer</h2></div></div></div><p> +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +</p></div><div class="section" title="Partitioning"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id330240"></a>Partitioning</h2></div></div></div><p> +Unlike many other Linux distributions, Slackware does not make use of a +graphical disk partitioning tool in its installer. Rather, Slackware +makes use of <span class="application">fdisk</span>(8) and +<span class="application">cfdisk</span>(8), both console tools. +<span class="application">cfdisk</span> is a curses-based partitioning tool +while <span class="application">fdisk</span> is not. Whichever you choose to +use should only rarely matter. In this book, we'll only discuss +<span class="application">fdisk</span>. +</p><p> +In order to partition your hard drive, you'll first need to know how to +identify it. In Linux, all hardware is identified by a special file +called a device file. These are all (typically) located in the +<code class="filename">/dev</code> directory. If your hard drive is IDE, you +will most likely find it as <code class="filename">/dev/hda</code>; however, +many hard drives today including SATA disks are identified as SCSI +devices by the kernel. If you don't know what your hard drive is +identified in Linux as, <span class="application">fdisk</span> can help you +out. +</p><pre class="screen"><code class="prompt">root@slackware:/# </code><strong class="userinput"><code>fdisk -l</code></strong> + +Disk /dev/sda: 72.7 GB, 72725037056 bytes +255 heads, 63 sectors/track, 8841 cylinders +Units = cylinders of 16065 * 512 = 8225280 bytes +</pre><p> +Here, you can see that my system has a hard drive located at +<code class="filename">/dev/sda</code> that is 72.7 GB in size. You can also +see some additional info about this hard drive. (In my case, this is +actually three SCSI hard drives on a hardware RAID controller that +makes them appear as a single drive.) The [-l] argument to +<span class="application">fdisk</span> tells it to display the hard drives +and all the partitions it finds on those drives, but won't make any +changes to the disks. In order to actually partition our drives, we'll +have to tell <span class="application">fdisk</span> what drive to operate on. +</p><pre class="screen"><code class="prompt">root@slackware:/# </code><strong class="userinput"><code>fdisk /dev/sda</code></strong> + +The number of cylinders for this disk is set to 8841. +There is nothing wrong with that, but this is larger than 1024, +and could in certain setups cause problems with: +1) software that runs at boot time (e.g., old versions of LILO) +2) booting and partitioning software from other OSs + (e.g., DOS FDISK, OS/2 FDISK) + +Command (m for help): +</pre><p> +Now we've told fdisk what disk we wish to partition and it has dropped +us into command mode after printing an annoying warning message. The +1024 cylinder limit has not been a problem for some time, and +Slackware's boot loader will have no trouble booting disks larger than +this. Typing [m] and hitting ENTER will print out a helpful +message telling you what to do with <span class="application">fdisk</span>. +</p><pre class="screen">Command (m for help): <strong class="userinput"><code>m</code></strong> + +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! +FILL THIS IN! FILL THIS IN! + +</pre><p> +Now that we know what commands will do what, it's time to begin to +partition our drive. At a minimum, you will need a single +<code class="filename">/</code> partition and should create a swap partition. +You might also want to make a seperate <code class="filename">/home</code> +partition for storing user files (this will make it easier to upgrade +later, or install a different Linux operating system by keeping all of +your users' files on a seperate partition). So, let's go ahead and +make three partitions. The command to create a new partition is + [n] (which you would have noticed if you read the help). +</p><pre class="screen">Command: (me for help): <strong class="userinput"><code>n</code></strong> +Command action + e extended + p primary partition (1-4) +<strong class="userinput"><code>p</code></strong> +Partition number (1-4): <strong class="userinput"><code>1</code></strong> +First cylinder (1-8841, default 1): <strong class="userinput"><code>1</code></strong> +Last cylinder or +size or +sizeM or +sizeK (1-8841, default 8841): <strong class="userinput"><code>+8G</code></strong> + +Command (m for help): n +Command action + e extended + p primary partition (1-4) +<strong class="userinput"><code>p</code></strong> +Partition number (1-4): <strong class="userinput"><code>2</code></strong> +First cylinder (975-8841, default 975): <strong class="userinput"><code>975</code></strong> +Last cylinder or +size or +sizeM or +sizeK (975-8841, default 8841): <strong class="userinput"><code>+1G</code></strong> +</pre><p> +Here we have created two partitions. The first is 8GB in size and the +second is only 1GB. We can view our existing partitions with the +[p] command. +</p><pre class="screen"> Command (m for help): <strong class="userinput"><code>p</code></strong> + +Disk /dev/sda: 72.7 GB, 72725037056 bytes +255 heads, 63 sectors/track, 8841 cylinders +Units = cylinders of 16065 * 512 = 8225280 bytes + + Device Boot Start End Blocks Id System +/dev/sda1 1 974 7823623+ 83 Linux +/dev/sda2 975 1097 987997+ 83 Linux + +</pre><p> +Both of these partitions are of type "83" which is the standard Linux +filesystem. We will need to change <code class="filename">/dev/sda2</code> to +type "82" in order to make this a swap partition. We will do this with +the [t] command. +</p><pre class="screen">Command (m for help): <strong class="userinput"><code>t</code></strong> +Partition number (1-4): <strong class="userinput"><code>2</code></strong> +Hex code (type L to list codes): <strong class="userinput"><code>82</code></strong> + +Command (me for help): <strong class="userinput"><code>p</code></strong> + +Disk /dev/sda: 72.7 GB, 72725037056 bytes +255 heads, 63 sectors/track, 8841 cylinders +Units = cylinders of 16065 * 512 = 8225280 bytes + + Device Boot Start End Blocks Id System +/dev/sda1 1 974 7823623+ 83 Linux +/dev/sda2 975 1097 987997+ 82 Linux swap + +</pre><p>The swap partition is a special partition that is used for +virtual memory by the Linux kernel. If for some reason you run out of +RAM, the kernel will move the contents of some of the RAM to swap in +order to prevent a crash. The size of your swap partition is up to +you. A great many people have participated have participated in a +great many flamewars on the size of swap partitions, but a good rule of +thumb is to make your swap partition about twice the size of your +system's RAM. Since my machine has only 512MB of RAM, I decided to +make my swap partition 1GB. You may wish to experiment with your swap +partition's size and see what works best for you, but generally there +is no harm in having "too much" swap. +</p><p> +At this point we can stop, write these changes to the disk, and +continue on, but I'm going to go ahead and make a third partition which +will be mounted at <code class="filename">/home</code>. +</p><pre class="screen">Command: (me for help): <strong class="userinput"><code>n</code></strong> +Command action + e extended + p primary partition (1-4) +<strong class="userinput"><code>p</code></strong> +Partition number (1-4): <strong class="userinput"><code>3</code></strong> +First cylinder (1098-8841, default 1098): <strong class="userinput"><code>1098</code></strong> +Last cylinder or +size or +sizeM or +sizeK (1098-8841, default 8841): <strong class="userinput"><code>8841</code></strong> +</pre><p> +Now it's time to finish up and write these changes to disk. +</p><pre class="screen">Command: (me for help): <strong class="userinput"><code>w</code></strong> +The partition table has been altered! + +Calling ioctl() to re-read partition table. +Synching disks. +<code class="prompt">root@slackware:/# </code> +</pre><p> +At this point, we are through partitioning our disks and are ready to +begin the <span class="application">setup</span> program. However, if you +have created any extended partitions, you may wish to reboot once to +ensure that they are properly read by the kernel. +</p></div><div class="section" title="The setup Program"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id326672"></a>The <span class="application">setup</span> Program</h2></div></div></div><div class="section" title="Help"><div class="titlepage"><div><div><h3 class="title"><a name="id326687"></a>Help</h3></div></div></div></div><div class="section" title="Keymap"><div class="titlepage"><div><div><h3 class="title"><a name="id326694"></a>Keymap</h3></div></div></div></div><div class="section" title="Addswap"><div class="titlepage"><div><div><h3 class="title"><a name="id326702"></a>Addswap</h3></div></div></div></div><div class="section" title="Target"><div class="titlepage"><div><div><h3 class="title"><a name="id326709"></a>Target</h3></div></div></div></div><div class="section" title="Source"><div class="titlepage"><div><div><h3 class="title"><a name="id326717"></a>Source</h3></div></div></div></div><div class="section" title="Select"><div class="titlepage"><div><div><h3 class="title"><a name="id326724"></a>Select</h3></div></div></div></div><div class="section" title="Install"><div class="titlepage"><div><div><h3 class="title"><a name="id326732"></a>Install</h3></div></div></div></div><div class="section" title="Configure"><div class="titlepage"><div><div><h3 class="title"><a name="id326739"></a>Configure</h3></div></div></div></div></div></div><div class="chapter" title="Chapter 3. Booting"><div class="titlepage"><div><div><h2 class="title"><a name="id297222"></a>Chapter 3. Booting</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id357891"><span class="application">mkinitrd</span></a></span></dt><dt><span class="section"><a href="#id326605">LILO</a></span></dt></dl></div><p> +Ok, now that you've gotten Slackware installed on your system, you +should learn exactly what controls the boot sequence of your machine, +and how to fix it should you manage to break it somehow. Use Linux long +enough, and sooner or later you will make a mistake that breaks your +bootloader. Fortunately, this doesn't require a re-install to fix. Unlike +many other operating systems that hide the underlying details of how they +work, Linux (and in particular, Slackware) gives you full control over +the boot process. Simply by editing a configuration file or two and +re-running the boot-loader installer, you can quickly and easily change +(or break) your system. Slackware even makes it easy to dual-boot +between multiple operating systems such as other Linux distributions or +Microsoft Windows. +</p><div class="section" title="mkinitrd"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id357891"></a><span class="application">mkinitrd</span></h2></div></div></div><p> +Before we go any further, a quick discussion on the Linux kernel is +warranted. Slackware Linux includes several different kernels. While +they are all compiled from the same source code, and hence are the +"same", they are not identical. Depending on your architecture and +Slackware version, the installer may have loaded your system with +several kernels. There are kernels for single-processor +systems and kernels for multi-processor systems. In the old days, there +were tons of kernels for installing on different kinds of hard drive +controllers. More importantly for our discussion, there are "huge" +kernels and "generic" kernels. +</p><p> +If you look inside your <code class="filename">/boot</code> directory, you'll +see the various kernels installed on your system. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /boot/vmlinuz*</code></strong> +/boot/vmlinuz-huge-2.6.29.4 /boot/vmlinuz-generic-2.6.29.4 +</pre><p> +Here you can see that I have two kernels installed, +<code class="filename">vmlinuz-huge-2.6.29.4</code> and +<code class="filename">vmlinuz-generic-2.6.29.4</code>. Each Slackware release +includes different kernel versions and sometimes even slightly +different names, so don't be alarmed if what you see doesn't exactly +match what I have listed here. +</p><p> +Huge kernels are exactly what you might think; they're huge. These +kernels are built to support nearly every conceivable computer +Slackware is supported on. They most certainly contain support for +hardware your machine does not, and never will, have. These are +included for several reasons, but the most important perhaps is in use +by the installer. These are the kernels the Slackware installation +disks run. If you chose to let the installer configure your bootloader +for you, it chooses to use these kernels due to the incredible variety +of hardware they support. By contrast, the generic kernels support very +little hardware without the use of external modules. If you want to use +one of the generic kernels, you'll need to make use of something called +an initrd, and the tool to make them, +<span class="application">mkinitrd</span>(8). +</p><p> +So why should you use a generic kernel? Currently the Slackware +development team recommends use of a generic kernel for a variety of +reasons. Perhaps the most obvious is size. The huge kernels are +currently about twice the size of the generic kernels before they are +uncompressed and loaded into memory. If you are running an older +machine, or one with some small ammount of RAM, you will appreciate the +savings the generic kernels offer you. Other reasons are somewhat more +difficult to quantify. Conflicts between drivers included in the huge +kernels do appear from time-to-time, and generally speaking, the huge +kernels do not perform as well as the generic ones. Also, by using the +generic kernels, special arguments can be passed to hardware drivers +seperately, rather than requiring these options be passed on the kernel +command line. Some of the tools included with Slackware work better if +your kernel uses some drivers as modules rather than "hard-coding" them +into the kernel. If you're having trouble understanding this, don't be +alarmed, just think "huge kernel: good, generic kernel: better". +</p><p> +Unfortunately, using the generic kernels isn't as straight-forward as +using the huge kernels. In order for the generic kernel to boot your +system, you must also usually include a few basic modules in an +initird. Modules are pieces of compiled kernel code that can be +inserted or removed from a running kernel. This makes the system +somewhat more flexible at the cost of a tiny bit of added complexity. +You might find it easier to think of modules as device drivers, at +least for this section. Typically you will need to add the module for +whatever filesystem you chose to use for your root partition during the +installer. If your root partition is located on a SCSI disk or RAID +controller, you'll need to load those modules as well. Finally, if +you're using software RAID, disk encryption, or LVM, you'll also need +to create an initrd whether you're using the generic kernel or not. +</p><p> +initrds are compressed <span class="application">cpio</span>(1) archives, so +creating them isn't very straightforward. Fortunately for you, +Slackware includes a tool that makes this very easy, +<span class="application">mkinitrd</span>. A full discussion of +<span class="application">mkinitrd</span> is a bit beyond the scope of this +book, but we'll show you all the highlights. For a more complete +explanation, check the manpage or run +<span class="application">mkinitrd</span> with the [--help] +argument. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mkinitrd --help</code></strong> +mkinitrd creates an initial ramdisk (actually an initramfs cpio+gzip +archive) used to load kernel modules that are needed to mount the +root filesystem, or other modules that might be needed before the +root filesystem is available. Other binaries may be added to the +initrd, and the script is easy to modify. Be creative. :-) +.... many more lines deleted .... +</pre><p> +When using <span class="application">mkinitrd</span>, you'll need to know a +few items of information: your root partition, your root filesystem, +any hard disk controllers you're using, and whether or not you're using +LVM, software RAID, or disk encryption. Unless you're using some kind +of SCSI controller (and have your root partition loaded on the SCSI +controller), you should only need to know your root filesystem and +partition type. Assuming you've booted into your Slackware installation +using the huge kernel, you can easily find this information with the +<span class="application">mount</span> command. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount</code></strong> +/dev/sda1 on / type ext4 (rw,barrier=1,data=ordered) +proc on /proc type proc (rw) +sysfs on /sys type sysfs (rw) +usbfs on /proc/bus/usb type usbfs (rw) +/dev/sda2 on /home type jfs (rw) +tmpfs on /dev/shm type tmpfs (rw) +</pre><p> +In the example provided, you can see that the root partition is located +on <code class="filename">/dev/sda1</code> and is an ext4 type partition. If we +want to create an initrd for this system, we simply need to tell this +information to <span class="application">mkinird</span>. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mkinitrd -f ext4 -r /dev/sda1</code></strong> +</pre><p> +Note that in most cases, <span class="application">mkinitrd</span> is smart +enough to determine this information on its own, but it never hurts to +specify it manually. Now that we've created out initrd, we simply need +to tell LILO where to find it. We'll focus on that in the next section. +</p><p> +Looking up all those different options for +<span class="application">mkinitrd</span> or worse, memorizing them, can be a +real pain though, especially if you try out different kernels +consistently. This became tedious for the Slackware development team, +so they came up with a simple configuration file, +<code class="filename">mkinitrd.conf</code>(5). You can find a sample file that +can be easily customized for your system under the +<code class="filename">/etc</code> directory. Here's mine. +</p><pre class="screen"># mkinitrd.conf.sample +# See "man mkinitrd.conf" for details on the syntax of this file +# +SOURCE_TREE="/boot/initrd-tree" +CLEAR_TREE="0" +OUTPUT_IMAGE="/boot/initrd.gz" +KERNEL_VERSION="$(uname -r)" +#KEYMAP="us" +MODULE_LIST="ext3:ext4:jfs" +#LUKSDEV="/dev/hda1" +ROOTDEV="/dev/raven/64root" +ROOTFS="ext4" +#RESUMEDEV="/dev/hda2" +#RAID="0" +LVM="1" +#WAIT="1" +</pre><p> +For a complete description of each of these lines and what they do, +you'll need to consulte the man page for +<code class="filename">mkinitrd.conf</code>. Once each of these is setup, you +need only run <span class="application">mkinitrd</span> with the + [-F] argument. A proper initrd file will be constructed and +installed for you, without you having to remember all those obscure +arguments. +</p></div><div class="section" title="LILO"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id326605"></a>LILO</h2></div></div></div><p> +LILO is the Linux Loader, and currently the default boot loader +installed with Slackware Linux. If you've used other Linux +distributions before, you may be more familiar with GRUB. If you prefer +to use it, you can easily find it in the <code class="filename">extra/</code> +directory on one of your Slackware CDs. Since LILO is the default +Slackware bootloader however, we'll focus exclusively on it. +</p><p> +Configuring LILO can be a little daunting for new users, so Slackware +comes with a special setup tool, <span class="application">liloconfig</span>. +Normally, <span class="application">liloconfig</span> is first run by the +installer, but you can run it at anytime from a terminal. +</p><p> +FILL THIS IN!!!! Picture of liloconfig +</p><p> +<span class="application">liloconfig</span> has two modes of operation: +simple and expert. The simple mode tries to automatically configure +lilo for you. If Slackware is the only operating system installed on +your computer, the simple mode will almost always do the right thing +quickly and easily. It is also very good at detecting Windows +installations and adding them to the <code class="filename">lilo.conf</code> +file so that you can choose which operating system to boot when you +turn your computer on. +</p><p> +In order to use expert mode, you'll need to know Slackware's root +partition. You can also setup other linux operating systems if you know +their root partitions, but this may not work as well as you'd expect. +<span class="application">liloconfig</span> will try to boot each linux +operating system with Slackware's kernel, and this is probably not what +you want. Fortunately, setting up Windows partitions in expert mode is +trivial. One hint when using expert mode. You should almost always +install LILO to the Master Boot Record (MBR). Once upon a time, it was +recommended to install the boot loader onto the root partition and set +that partition as bootable. Today, LILO has matured greatly and is safe +to install on the MBR. In fact, you will encounter fewer problems if +you do so. +</p><p> +<span class="application">liloconfig</span> is a great way to quickly setup +your boot loader, but if you really need to know what's going on you'll +need to look at LILO's configuration file, +<code class="filename">lilo.conf</code>(5) under the <code class="filename">/etc</code> +directory. The <code class="filename">lilo.conf</code> file is seperated into +several sections. At the top you'll find a global section where you +specify things like where to install LILO (generally the MBR), any +special images or screens to show on boot, and the timeout after which +LILO will boot the default operating system. Here's what the global +section of my lilo.conf file looks like in part. +</p><pre class="screen"># LILO configuration file + +boot = /dev/sda + bitmap = /boot/slack.bmp + bmp-colors = 255,0,255,0,255,0 + bmp-table = 60,6,1,16 + bmp-timer = 65,27,0,255 + +append=" vt.default_utf8=0" +prompt +timeout = 50 + +# VESA framebuffer console @ 1024x768x256 +vga = 773 +.... many more lines ommitted .... +</pre><p> +For a complete listing of all the possible LILO options, you should +consult the man page for <code class="filename">lilo.conf</code>. In brief, +we'll discuss the most common in this document. +</p><p> +The first thing that should draw your attention is the boot line. This +determines where the bootloader is installed. In order to install the +the MBR of your hard drive, you simply list the hard drive's device +entry on this line. In my case, I'm using a SATA hard drive that shows +up as SCSI device <code class="filename">/dev/sda</code>. If you're using an IDE +drive, you will probably have to use <code class="filename">/dev/hda</code>. In +order to install to the boot block of a partition, you'll have to list +the partition's device entry. For example, if you are installing to the +first partition on the only SATA hard drive in your computer, you would +probably use <code class="filename">/dev/sda1</code>. +</p><p> +The prompt option simply tells LILO to ask (prompt) you for which +operating system to boot. Operating systems are each listed in their +own section deeper in the file. We'll get to them in a minute. The +timeout option tells LILO how long to wait (in tenths of seconds) +before booting the default OS. In my case, this is 5 seconds. Some +systems seem to take a very long time to display the boot screen, so +you may need to use a larger timeout value than I have set. This is in +part why the simple LILO installation method utilizes a very long +timeout (somewhere around 2 whole minutes). The append line in my case +was setup by <span class="application">liloconfig</span>. You may (and +probably should) see something similar when looking at your own +<code class="filename">lilo.conf</code>. I won't go into the details of why this +line is needed, so you're just going to have to trust me that things +work better if it is present. :^) +</p><p> +Now that we've looked into the global section, let's take a look at the +operating systems section. Each linux operating system section begins +with an "image" line. Microsoft Windows operating systems are specified +with an "other" line. Let's take a look at a sample +<code class="filename">lilo.conf</code> that boots both Slackware and Microsoft +Windows. +</p><pre class="screen"># LILO configuration file +... global section ommitted .... +# Linux bootable partition config begins +image = /boot/vmlinuz-generic-2.6.29.4 + root = /dev/raven/64root + initrd = /boot/initrd.gz + label = Slackware64 + read-only +# Linux bootable partition config ends +# Windows bootable partition config begins +other = /dev/sda3 + label = Windows + table = /dev/sda +# Windows bootable partition config ends +</pre><p> +For Linux operating systems like Slackware, the image line specifies +which kernel to boot. In this case, we're booting +<code class="filename">/boot/vmlinuz-generic-2.6.29.4</code>. The remaining +sections are pretty self-explainatory. The tell LILO where to find the +root filesystem, what initrd (if any) to use, and to initially mount +the root filesystem read-only. That initrd line is very important for +anyone running a generic kernel, or using LVM or software RAID. It +tells LILO (and the kernel) where to find the initrd you created using +<span class="application">mkinitrd</span>. +</p><p> +Once you've gotten your <code class="filename">lilo.conf</code> setup for your +machine, simply run <span class="application">lilo</span>(8) to install it. +Unlike GRUB and other bootloaders, LILO requires you re-run +<span class="application">lilo</span> anytime you make changes to its +configuration file in order for those changes to be installed. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>lilo</code></strong> +Warning: LBA32 addressing assumed +Warning: '/proc/partitions' does not match '/dev' directory structure. + Name change: '/dev/dm-0' -> '/dev/raven/swap' +Warning: Name change: '/dev/dm-1' -> '/dev/raven/root' +Warning: Name change: '/dev/dm-2' -> '/dev/raven/home' +Warning: Name change: '/dev/dm-3' -> '/dev/raven/src' +Warning: Name change: '/dev/dm-4' -> '/dev/raven/64root' +Added Slackware * +Added Backup +6 warnings were issued. +</pre><p> +Don't be scared by many of the warnings you may see when running +<span class="application">lilo</span>. In my case, most of these warnings are +issued by the use of LVM. Unless you see a fatal error, things should +be just fine. +</p></div></div><div class="chapter" title="Chapter 4. Basic Shell Commands"><div class="titlepage"><div><div><h2 class="title"><a name="id288954"></a>Chapter 4. Basic Shell Commands</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id326497">System Documentation</a></span></dt><dt><span class="section"><a href="#id330395">Dealing with Files and Directories</a></span></dt><dd><dl><dt><span class="section"><a href="#id330401"><span class="application">Listing Files and Directory Contents</span></a></span></dt><dt><span class="section"><a href="#id351195">Moving Around the Filesystem</a></span></dt><dt><span class="section"><a href="#id354028">File and Directory Creation and Deletion</a></span></dt></dl></dd><dt><span class="section"><a href="#id354344">Reading Documents</a></span></dt><dt><span class="section"><a href="#id354528">Linking</a></span></dt></dl></div><p> +So you've installed Slackware and you're staring at a terminal prompt, +what now? Now would be a good time to learn about the basic command +line tools. And since you're staring at a blinking curser, you +probably need a little assistance in knowing how to get around, and +that is what this chapter is all about. +</p><div class="section" title="System Documentation"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id326497"></a>System Documentation</h2></div></div></div><p> +Your Slackware Linux system comes with lots of built-in documentation +for nearly every installed application. Perhaps the most common method +of reading system documentation is by using the +<span class="application">man</span>(1). <span class="application">man</span> +(short for manual) will bring up the included man-page for any +application, system call, configuration file, or library you tell it +too. For example, <strong class="userinput"><code>man man</code></strong> will bring up the +man-page for <span class="application">man</span> itself. +</p><p> +Unfortunately, you may not always know what application you need to use +for the task at hand. Thankfully, <span class="application">man</span> has +built-in search abilities. Using the [-k] switch +will cause <span class="application">man</span> to search for every man-page +that matches your search terms. +</p><p> +The man-pages are organized into groups or sections by their content +type. For example, section 1 is for user applications. +<span class="application">man</span> will search each section in order and +display the first match it finds. Sometimes you will find that a +man-page exists in more than one section for a given entry. In that +case, you will need to specify the exact section to look in. In this +book, all applications and a number of other things will have a number +on their right-hand side in parenthesis. This number is the man page +section where you will find information on that tool. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>man -k printf</code></strong> +printf (1) - format and print data +printf (3) - formatted output conversion +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>man 3 printf</code></strong> +</pre><div class="table"><a name="id333534"></a><p class="title"><b>Table 4.1. Man Page Sections</b></p><div class="table-contents"><table summary="Man Page Sections" border="0"><colgroup><col><col></colgroup><thead><tr><th>Section</th><th align="right">Contents</th></tr></thead><tbody><tr><td>1</td><td align="right">User Commands</td></tr><tr><td>2</td><td align="right">System Calls</td></tr><tr><td>3</td><td align="right">C Library Calls</td></tr><tr><td>4</td><td align="right">Devices</td></tr><tr><td>5</td><td align="right">File Formats / Protocols</td></tr><tr><td>6</td><td align="right">Games</td></tr><tr><td>7</td><td align="right">Conventions / Macro Packages</td></tr><tr><td>8</td><td align="right">System Administration</td></tr></tbody></table></div></div><br class="table-break"></div><div class="section" title="Dealing with Files and Directories"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id330395"></a>Dealing with Files and Directories</h2></div></div></div><div class="section" title="Listing Files and Directory Contents"><div class="titlepage"><div><div><h3 class="title"><a name="id330401"></a><span class="application">Listing Files and Directory Contents</span></h3></div></div></div><p> +<span class="application">ls</span>(1) is used to list files and directories, +their permissions, size, type, inode number, owner and group, and +plenty of additional information. For example, let's list what's in +the <code class="filename">/</code> directory for your new Slackware Linux system. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls /</code></strong> +bin/ dev/ home/ lost+found/ mnt/ proc/ sbin/ sys/ usr/ +boot/ etc/ lib/ media/ opt/ root/ srv/ tmp/ var/ +</pre><p>Notice that each of the listings is a directory. These are +easily distinguished from regular files due to the trailing /; standard +files do not have a suffix. Additionally, executable files will have an +asterisk suffix. But <span class="application">ls</span> can do so much +more. To get a view of the permissions of a file or directory, you'll +need to do a "long list". +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -l /home/alan/Desktop</code></strong> +-rw-r--r-- 1 alan users 15624161 2007-09-21 13:02 9780596510480.pdf +-rw-r--r-- 1 alan users 3829534 2007-09-14 12:56 imgscan.zip +drwxr-xr-x 3 alan root 168 2007-09-17 21:01 ipod_hack/ +drwxr-xr-x 2 alan users 200 2007-12-03 22:11 libgpod/ +drwxr-xr-x 2 alan users 136 2007-09-30 03:16 playground/ +</pre><p> +A long listing lets you view the permisions, user and group ownership, +file size, last modified date, and of course, the file name itself. +Notice that the first two entires are files, and the last three are +directories. This is denoted by the very first character on the line. +Regular files get a "-"; directories get a "d". There are several +other file types with their own denominators. Symbolic links for +example will have an "l". +</p><p> +Lastly, we'll show you how to list dot-files, or hidden files. Unlike +other operating systems such as Microsoft Windows, there is no special +property that differentiates "hidden" files from "unhidden" files. A +hidden file simply begins with a dot. To display these files along +with all the others, you just need to pass the [-a] argument to +<span class="application">ls</span>. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -a</code></strong> +.xine/ .xinitrc-backup .xscreensaver .xsession-errors SBo/ +.xinitrc .xinitrc-xfce .xsession .xwmconfig/ Shared/ +</pre><p> +You also likely noticed that your files and directories appear in +different colors. Many of the enhanced features of +<span class="application">ls</span> such as these colors or the trailing +characters indicating file-type are special features of the +<span class="application">ls</span> program that are turned on by passing +various arguments. As a convienience, Slackware sets up +<span class="application">ls</span> to use many of these optional arguments +by default. These are controlled by the LS_OPTIONS and LS_COLORS +environment variables. We will talk more about environment variables +in chapter 5. +</p></div><div class="section" title="Moving Around the Filesystem"><div class="titlepage"><div><div><h3 class="title"><a name="id351195"></a>Moving Around the Filesystem</h3></div></div></div><p> +<span class="application">cd</span> is the command used to change +directories. Unlike most other commands, <span class="application">cd</span> +is actually not it's own program, but is a shell built-in. Basically, +that means <span class="application">cd</span> does not have its own man +page. You'll have to check your shell's documentation for more details +on the <span class="application">cd</span> you may be using. For the most +part though, they all behave the same. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cd /</code></strong> +<code class="prompt">darkstar:/$</code><strong class="userinput"><code>ls</code></strong> +bin/ dev/ home/ lost+found/ mnt/ proc/ sbin/ sys/ usr/ +boot/ etc/ lib/ media/ opt/ root/ srv/ tmp/ var/ +<code class="prompt">darkstar:/$</code><strong class="userinput"><code>cd /usr/local</code></strong> +<code class="prompt">darkstar:/usr/local$</code> +</pre><p> +Notice how the prompt changed when we changed directories? The default +Slackware shell does this as a quick, easy way to see your current +directory, but this is not actually a function of +<span class="application">cd</span>. If your shell doesn't operate in this +way, you can easily get your current working directory with the +<span class="application">pwd</span>(1) command. (Most UNIX shells have +configurable prompts that can be coaxed into providing this same +functionality. In fact, this is another convience setup in the default +shell for you by Slackware.) +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>pwd</code></strong> +/usr/local +</pre></div><div class="section" title="File and Directory Creation and Deletion"><div class="titlepage"><div><div><h3 class="title"><a name="id354028"></a>File and Directory Creation and Deletion</h3></div></div></div><p> +While most applications can and will create their own files and +directories, you'll often want to do this on your own. Thankfully, +it's very easy using <span class="application">touch</span>(1) and +<span class="application">mkdir</span>(1). +</p><p> +<span class="application">touch</span> actually modifies the timestamp on a +file, but if that file doesn't exist, it will be created. +</p><pre class="screen"><code class="prompt">darkstar:~/foo$ </code><strong class="userinput"><code>ls -l</code></strong> +-rw-r--r-- 1 alan users 0 2008-01-18 15:01 bar1 +<code class="prompt">darkstar:~/foo$ </code><strong class="userinput"><code>touch bar2</code></strong> +-rw-r--r-- 1 alan users 0 2008-01-18 15:01 bar1 +-rw-r--r-- 1 alan users 0 2008-01-18 15:05 bar2 +<code class="prompt">darkstar:~/foo$ </code><strong class="userinput"><code>touch bar1</code></strong> +-rw-r--r-- 1 alan users 0 2008-01-18 15:05 bar1 +-rw-r--r-- 1 alan users 0 2008-01-18 15:05 bar2 +</pre><p> +Note how <code class="filename">bar2</code> was created in our second command, +and the third command simpl updated the timestamp on +<code class="filename">bar1</code> +</p><p> +<span class="application">mkdir</span> is used for (obviously enough) making +directories. <strong class="userinput"><code>mkdir foo</code></strong> will create the +directory "foo" within the current working directory. Additionally, +you can use the [-p] argument to create any +missing parent directories. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>mkdir foo</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>mkdir /slack/foo/bar/</code></strong> +mkdir: cannot create directory `/slack/foo/bar/': No such file or directory +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>mkdir -p /slack/foo/bar/</code></strong> +</pre><p> +In the latter case, <span class="application">mkdir</span> will first create +"/slack", then "/slack/foo", and finally "/slack/foo/bar". If you +failed to use the [-p] argument, +<span class="application">man</span> would fail to create "/slack/foo/bar" +unless the first two already existed, as you saw in the example. +</p><p> +Removing a file is as easy as creating one. The +<span class="application">rm</span>(1) will remove a file (assuming of course +that you have permission to do this). There are a few very common +arguments to <span class="application">rm</span>. The first is + [-f] and is used to force the removal of a file +that you may lack explicit permission to delete. The + [-r] argument will remove directories and their +contents recursively. +</p><p> +There is another tool to remove directories, the humble +<span class="application">rmdir</span>(1). <span class="application">rmdir</span> +will only remove directories that are empty, and complain noisely about +those that contain files or sub-directories. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls</code></strong> +foo_1/ foo_2/ +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls foo_1</code></strong> +bar_1 +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rmdir foo_1</code></strong> +rmdir: foo/: Directory not empty +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rm foo_1/bar</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rmdir foo_1</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls foo_2</code></strong> +bar_2/ +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rm -fr foo_2</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls</code></strong> +</pre></div></div><div class="section" title="Reading Documents"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id354344"></a>Reading Documents</h2></div></div></div><p> +Traditionally, UNIX and UNIX-like operating systems are filled with +text files that at some point in time the system's users are going to +want to read. Naturally, there are plenty of ways of reading these +files, and we'll show you the most common ones. +</p><p> +In the early days, if you just wanted to see the contents of a file +(any file, whether it was a text file or some binary program) you would +use <span class="application">cat</span>(1) to view them. +<span class="application">cat</span> is a very simple program, which takes +one or more files, concatenates them (hence the name) and sends them to +the standard output, which is usually your terminal screen. This was +fine when the file was small and wouldn't scroll off the screen, but +inadequate for larger files as it had no built-in way of moving within +a document and reading it a paragraph at a time. Today, +<span class="application">cat</span> is still used quite extensively, but +predominately in scripts or for joining two or more files into one. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat /etc/slackware-version</code></strong> +Slackware 12.0.0 +</pre><p> +Given the limitations of <span class="application">cat</span> some very +intelligent people sat down and began to work on an application to let +them read documents one page at a time. Naturally, such applications +began to be known as "pagers". One of the earliest of these was +<span class="application">more</span>(1), named because it would let you see +"more" of the file whenever you wanted. <span class="application">more</span> +will display the first few lines of a text file until your screen is +full, then pause. Once you've read through that screen, you can +proceed down one line by pressing ENTER, or an entire screen by +pressing SPACE. <span class="application">more</span> is also capable of +searching through a text file for keywords. Once you've displayed a +file in <span class="application">more</span>, simply press the / key and +enter a keyword. Upon pressing ENTER, the text will scroll until it +finds the next match. This is clearly a big improvement over +<span class="application">cat</span>, but still suffers from a serious flaw: +<span class="application">more</span> is not able to scroll back up through +the file to allow you to read something you might have missed. Clearly +a better solution is called for. +</p><p> +In order to address the short-comings of +<span class="application">more</span>, a new pager was developed and +ironically dubbed <span class="application">less</span>(1). +<span class="application">less</span> is a very powerful pager that supports +all of the functions of <span class="application">more</span> while adding +lots of additional features. To begin with, +<span class="application">less</span> allows you to use your arrow keys to +controll movement within the document. Due to its popularity, many +Linux distributions have begun to exclude +<span class="application">more</span> in favor of +<span class="application">less</span>. Slackware includes both. Moreover, +Slackware also includes a handy little pre-processor for +<span class="application">less</span> called +<code class="filename">lesspipe.sh</code>. This allows a user to exectute +<span class="application">less</span> on a number of non-text files. +<code class="filename">lesspipe.sh</code> will generate text output from running +a command on these files, and display it in +<span class="application">less</span>. +</p></div><div class="section" title="Linking"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id354528"></a>Linking</h2></div></div></div><p> +Links are a method of referring to one file by more than one name. By +using the <span class="application">ln</span>(1) application, a user can +reference one file with more than one name. The two files are not +carbon-copies of one another, but rather are the exact same file, just +with a different name. To remove the file entirely, all of its names +must be deleted. (This is actually the result of the way that +<span class="application">rm</span> and other tools like it work. Rather +than remove the contents of the file, they simply remove the reference +to the file, freeing that space to be re-used. +<span class="application">ln</span> will create a second reference or "link" +to that file.) +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ln /etc/slackware-version foo</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat foo</code></strong> +Slackware 12.0.0 +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -l /etc/slackware-version foo</code></strong> +-rw-r--r-- 1 root root 17 2007-06-10 02:23 /etc/slackware-version +-rw-r--r-- 1 root root 17 2007-06-10 02:23 foo +</pre><p> +Another type of link exists, the symlink. Symlinks, rather than being +another reference to the same file, are actually a special kind of file +in their own right. These symlinks point to another file or directory. +The primary advantage of symlinks is that they can refer to directories +as well as files, and they can span multiple filesystems. These are +created with the [-s] argument. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ln -s /etc/slackware-version foo</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat foo</code></strong> +Slackware 12.0.0 +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -l /etc/slackware-version foo</code></strong> +-rw-r--r-- 1 root root 17 2007-06-10 02:23 /etc/slackware-version +lrwxrwxrwx 1 root root 22 2008-01-25 04:16 foo -> /etc/slackware-version +</pre><p> +When using symlinks, remember that if the original file is deleted, +your symlink is useless; it simply points at a file that doesn't exist +anymore. +</p></div></div><div class="chapter" title="Chapter 5. The Bourne Again Shell"><div class="titlepage"><div><div><h2 class="title"><a name="id336592"></a>Chapter 5. The Bourne Again Shell</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id282479">What Is A Shell?</a></span></dt><dt><span class="section"><a href="#id314358">Environment Variables</a></span></dt><dt><span class="section"><a href="#id313824">Wildcards</a></span></dt><dt><span class="section"><a href="#id335881">Tab Completion</a></span></dt><dt><span class="section"><a href="#id354670">Input and Output Redirection</a></span></dt><dt><span class="section"><a href="#id354937">Terminals</a></span></dt><dt><span class="section"><a href="#id355019">Customization</a></span></dt></dl></div><div class="section" title="What Is A Shell?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id282479"></a>What Is A Shell?</h2></div></div></div><p> +Yeah, what exactly is a shell? Well, a shell is basically a +command-line user environment. In essence, it is an application that +runs when the user logs in and allows him to run additional +applications. In some ways it is very similar to a graphical user +interface, in that it provides a framework for executing commands and +launching programs. There are many shells included with a full install +of Slackware, but in this book we're only going to discuss +<span class="application">bash</span>(1), the Bourne Again Shell. Advanced +users might want to consider using the powerful +<span class="application">zsh</span>(1), and users familiar with older UNIX +systems might appreciate <span class="application">ksh</span>. The truly +masochistic might choose the <span class="application">csh</span>, but new +users should stick to <span class="application">bash</span>. +</p></div><div class="section" title="Environment Variables"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id314358"></a>Environment Variables</h2></div></div></div><p> +All shells make certain tasks easier for the user by keeping track of +things in environment variables. An environment variable is simply a +shorter name for some bit of information that the user wishes to store +and make use of later. For example, the environment variable PS1 tells +<span class="application">bash</span> how to format its prompt. Other +variables may tell applications how to run. For example, the LESSOPEN +variable tells <span class="application">less</span> to run that handy +<code class="filename">lesspipe.sh</code> preprocessor we talked about, and +LS_OPTIONS tuns on color for <span class="application">ls</span>. +</p><p> +Setting your own envirtonment variables is easy. +<span class="application">bash</span> includes two built-in functions for +handling this: <span class="application">set</span> and +<span class="application">export</span>. Additionally, an environment +variable can be removed by using <span class="application">unset</span>. +(Don't panic if you accidently unset an environment variable and don't +know what it would do. You can reset all the default variables by +logging out of your terminal and logging back in.) You can reference a +variable by placing a dollar sign ($) in front of it. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>set FOO=bar</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo $FOO</code></strong> +bar +</pre><p> +The primary difference between <span class="application">set</span> and +<span class="application">export</span> is that +<span class="application">export</span> will (naturally) export the variable +to any sub-shells. (A sub-shell is simply another shell running inside +a parent shell.) You can easily see this behavior when working with +the PS1 variable that controls the <span class="application">bash</span> +prompt. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>set PS1='FOO '</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>export PS1='FOO '</code></strong> +<code class="prompt">FOO </code> +</pre><p> +There are many important environment variables that +<span class="application">bash</span> and other shells use, but one of the +most important ones you will run across is PATH. PATH is simply a list +of directories to search through for applications. For example, +<span class="application">top</span> is located at +<span class="application">/usr/bin/top</span>(1). You could run it simply by +specifying the complete path to it, but if +<code class="filename">/usr/bin</code> is in your PATH variable, +<span class="application">bash</span> will check there if you don't specify a +complete path one your own. You will most likely first notice this +when you attempt to run a program that is not in your PATH as a normal +user, for instance, <span class="application">ifconfig</span>(8). +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ifconfig</code></strong> +bash: ifconfig: command not found +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo $PATH</code></strong> +/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/opt/www/htdig/bin:. +</pre><p> +Above, you see a typical PATH for a mortal user. You can change it on +your own the same as any other environment variable. If you login as +root however, you'll see that root has a different PATH. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>su -</code></strong> +Password: +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>echo $PATH</code></strong> +/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/opt/www/htdig/bin +</pre></div><div class="section" title="Wildcards"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id313824"></a>Wildcards</h2></div></div></div><p> +Wildcards are special characters that tell the shell to match certain +criteria. If you have experience with DOS, you'll recognize * as a +wildcard that matches anything. <span class="application">bash</span> makes +use of this wildcard and several others to enable you to easily define +exactly what you want to do. +</p><p> +This first and most common of these is, of course, *. The asterisk +matches any character or combination of characters, including none. +Thus <strong class="userinput"><code>b*</code></strong> would match any files named b, ba, bab, +babc, bcdb, and so forth. Slightly less common is the ?. This +wildcard matches one instance of any character, so +<strong class="userinput"><code>b?</code></strong> would match ba and bb, but not b or bab. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>touch b ba bab</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls *</code></strong> +b ba bab +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls b?</code></strong> +ba +</pre><p> +No, the fun doesn't stop there! In addition to these two we also have +the bracket pair "[ ]" which allows us to fine tune exactly what we +want to match. Whenever <span class="application">bash</span> see the +bracket pair, it substitues the contents of the bracket. Any +combination of letters or numbers may be specified in the bracket as +long as they are comma seperacted. Additionally, ranges of numbers and +letters may be specified as well. This is probably best shown by +example. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls a[1-4,9]</code></strong> +a1 a2 a3 a4 a9 +</pre><p> +Since Linux is case-sensitive, capital and lower-case letters are +treated differently. All capital letters come before all lower-case +letters in "alphabetical" order, so when using ranges of capital and +lower-case letters, make sure to get them right. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls 1[W-b]</code></strong> +1W 1X 1Y 1Z 1a 1b +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls 1[w-B]</code></strong> +/bin/ls: cannot access 1[b-W]: No such file or directory +</pre><p> +In the second example, 1[b-W] isn't a valid range, so the shell treats +it as a filename, and since that file doesn't exist, +<span class="application">ls</span> tells you so. +</p></div><div class="section" title="Tab Completion"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id335881"></a>Tab Completion</h2></div></div></div><p> +Still think there's entirely too much work involved with using +wildcards? You're right. There's an even easier way when you're +dealing with long filenames: tab completion. Tab completion enables +you to type just enough of the filename to uniquely identify it, then +by hitting the TAB key, <span class="application">bash</span> will fill in +the rest for you. Even if you haven't typed in enough text to uniquely +identify a filename, the shell will fill in as much as it can for you. +Hitting TAB a second time will make it display a list of all possible +matches for you. +</p></div><div class="section" title="Input and Output Redirection"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id354670"></a>Input and Output Redirection</h2></div></div></div><p> +One of the defining features of Linux and other UNIX-like operating +systems is the number of small, relatively simple applications and the +ability to stack them together to create complex systems. This is +achieved by redirecting the output of one program to another, or by +drawing input from a file or second program. +</p><p> +To get started, we're going to show you how to redirect the output of a +program to a file. This is easily done with the '>' character. When +<span class="application">bash</span> sees the '>' character, it redirects +all of the standard output (also known as stdout) to whatever file name +follows. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo foo</code></strong> +foo +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo foo > /tmp/bar</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat /tmp/bar</code></strong> +foo +</pre><p> +In this example, we show you what <span class="application">echo</span> would +do if its stdout was not redirected to a file, then we re-direct it to +the <code class="filename">/tmp/bar</code> file. If <code class="filename">/tmp/bar</code> +does not exist, it is created and the output from +<span class="application">echo</span> is placed within it. If +<code class="filename">/tmp/bar</code> did exist, then its contents are +over-written. This might not be the best idea if you want to keep +those contents in place. Thankfully, <span class="application">bash</span> +supports '>>' which will append the output to the file. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo foo</code></strong> +foo +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo foo > /tmp/bar</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat /tmp/bar</code></strong> +foo +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>echo foo2 >> /tmp/bar</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat /tmp/bar</code></strong> +foo +foo2 +</pre><p> +You can also re-direct the standard error (or stderr) to a file. This +is slightly different in that you must use '2>' instead of just '>'. +(Since <span class="application">bash</span> can re-direct input, stdout, and +stderr, each must be uniquely identifiable. 0 is input, 1 is stdout, +and 2 is stderr. Unless one of these is specified, +<span class="application">bash</span> will make its best guess as to what you +actually meant, and assumed anytime you use '>' you only want to +redirect stdout. 1> would have worked just as well.) +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rm bar</code></strong> +rm: cannot remove `bar': No such file or directory +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>rm bar 2> /tmp/foo</code></strong> +<code class="prompt">darkstar:~$ </code><strong class="userinput"><code>cat /tmp/foo</code></strong> +rm: cannot remove `bar': No such file or directory +</pre><p> +You may also redirect the standard input (known as stdin) with the +'<' +character, though it's not used very often. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>fromdos < dosfile </code></strong> +</pre><p> +Finally, you can actually redirect the output of one program as input +to another. This is perhaps the most useful feature of +<span class="application">bash</span> and other shells, and is accomplished +using the '|' character. (This character is referred to as 'pipe'. +If you here some one talk of piping one program to another, this is +exactly what they mean.) +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ps auxw | grep getty</code></strong> +root 2632 0.0 0.0 1656 532 tty2 Ss+ Feb21 0:00 /sbin/agetty 38400 tty2 linux +root 3199 0.0 0.0 1656 528 tty3 Ss+ Feb15 0:00 /sbin/agetty 38400 tty3 linux +root 3200 0.0 0.0 1656 532 tty4 Ss+ Feb15 0:00 /sbin/agetty 38400 tty4 linux +root 3201 0.0 0.0 1656 532 tty5 Ss+ Feb15 0:00 /sbin/agetty 38400 tty5 linux +root 3202 0.0 0.0 1660 536 tty6 Ss+ Feb15 0:00 /sbin/agetty 38400 tty6 linux +</pre></div><div class="section" title="Terminals"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id354937"></a>Terminals</h2></div></div></div><p> +Slackware Linux and other UNIX-like operating systems allow users to +interact with them in many ways, but the most common, and arguably the +most useful, is the terminal. In the old days, terminals were keyboards +and monitors (sometimes even mice) wired into a mainframe or server via +serial connections. Today however, most terminals are virtual; that is, +they exist only in software. Virtual terminals allow users to connect +to the computer without requiring expensive and often incompatabile +hardware. Rather, a user needs only to run the software and they are +presented with a (usually) highly customizable virtual terminal. +</p><p> +The most common virtual terminals (in that every Slackware Linux machine +is going to have at least one) are the gettys. +<span class="application">agetty</span>(8) runs six instances by default on +Slackware, and allows local users (those who can physically sit down in +front of the computer and type at the keyboard) to login and run +applications. Each of these gettys is available on different tty +devices that are accessible seperately by pressing the +<span class="keycap"><strong>ALT</strong></span> key and one of the function keys from +<span class="keycap"><strong>F1</strong></span> through <span class="keycap"><strong>F6</strong></span>. Using these gettys +allows you to login multiple times, perhaps as different users, and run +applications in those users' shells silmutaneously. This is most +commonly done with servers which do not have +<span class="application">X</span> installed, but can be done on any machine. +</p><p> +On desktops, laptops, and other workstations where the user prefers a +graphical interface provided by <span class="application">X</span>, most +terminals are graphical. Slackware includes many different graphical +terminals, but the most commonly used are KDE's +<span class="application">konsole</span> and XFCE's +<span class="application">Terminal</span>(1) as well as the old standby, +xterm(1). If you are using a graphical interface, check your tool bars +or menus. Each desktop environment or window manager has a virtual +terminal (often called a terminal emulater), and they are all labelled +differently. Typically though, you will find them under a "System" +sub-menu in desktop environments. Executing any of these will give you +a graphical terminal and automatically run your default shell. +</p></div><div class="section" title="Customization"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id355019"></a>Customization</h2></div></div></div><p> +By now you should be pretty familiar with +<span class="application">bash</span> and you may have even noticed some odd +behavior. For example, when you login at the console, you're presented +with a prompt that looks a bit like this. +</p><pre class="screen"><code class="prompt">alan@darkstar:~$ </code></pre><p> +However, sometimes you'll see a much less helpful prompt like this one. +</p><pre class="screen"><code class="prompt">bash-3.1$ </code></pre><p> +The cause here is a special environment variable that controls the +<span class="application">bash</span> prompt. Some shells are considered +"login" shells and others are "interactive" shells, and both types read +different configuration files when started. Login shells read +<code class="filename">/etc/profile</code> and +<code class="filename">~/.bash_profile</code> when executed. Interactive shells +read <code class="filename">~/.bashrc</code> instead. This has some advantages +for power users, but is a common annoyance for many new users who want +the same environment anytime they execute +<span class="application">bash</span> and don't care about the difference +between login and interactive shells. If this applies to you, simply +edit your own ~/.bashrc file and include the following lines. +(For more information on +the different configuration files used, read the INVOCATION section of +the <span class="application">bash</span> man page.) +</p><pre class="screen"> +# ~/.bashrc +. /etc/profile +. ~/.bash_profile +</pre><p> +When using the above, all your login and interactive shells will have +the same environment settings and behave identically. Now, anytime we +wish to customize a shell setting, we only have to edit +<code class="filename">~/.bash_profile</code> for user-specific changes and +<code class="filename">/etc/profile</code> for global settings. Let's start by +configuring the prompt. +</p><p> +<span class="application">bash</span> prompts come in all shapes, colors, and +sizes, and every user has their own preferances. Personally, I prefer +short and simple prompts that take up a minimum of space, but I've seen +and used mutli-line prompts many times. One personal friend of mine +even included ASCII-art in his bash prompt. To change your prompt you +need only to change your PS1 variable. By default, Slackware attempts +to configure your PS1 variable thusly: +</p><pre class="screen"><code class="prompt">darkstar:~$ </code>echo $PS1 +\u@\h:\w\$ </pre><p> +Yes, this tiny piece of funny-looking figures controls your +<span class="application">bash</span> prompt. Basicaly, every character in +the PS1 variable is included in the prompt, unless it is a escaped by a +<span class="keycap"><strong>\</strong></span>, which tells <span class="application">bash</span> to +interpret it. There are many different escape sequences and we can't +discuss them all, but I'll explain these. The first "\u" translates to +the username of the current user. "\h" is the hostname of the machine +the terminal is attached to. "\w" is the current working directory, and +"\$" displays either a <span class="keycap"><strong>#</strong></span> or a <span class="keycap"><strong>$</strong></span> sign, +depending on whether or not the current user is root. A complete +listing of all prompt escape sequences is listed in the +<span class="application">bash</span> man page under the PROMPTING section. +</p><p> +Since we've gone through all this trouble to discuss the default +prompt, I thought I'd take some time to show you a couple example +prompts and the PS1 variable values needed to use them. +</p><pre class="screen"><code class="prompt">Wed Jan 14 12:08 AM +alan@raven:~$ </code>echo $PS1 +\d \@\n\u@\h:\w$ +<code class="prompt">HOST: raven - JOBS: 0 - TTY: 3 +alan@~/Desktop/sb_3.0:$ </code>echo $PS1 +HOST: \H - JOBS: \j - TTY: \l\n\u@\w:\$ +</pre><p> +For even more information on configuring your bash prompt, including +information on setting up colored prompts, refer to +<code class="filename">/usr/doc/Linux-HOWTOs/Bash-Prompt-HOWTO</code>. After +reading that for a short while, you'll get an idea of just how powerful +your <span class="application">bash</span> prompts can be. I once even had a +prompt that gave me up to date weather information such as temperature +and barometric pressure! +</p></div></div><div class="chapter" title="Chapter 6. The X Window System"><div class="titlepage"><div><div><h2 class="title"><a name="id325945"></a>Chapter 6. The X Window System</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id358884">What Is (And Isn't) X</a></span></dt><dt><span class="section"><a href="#id320754">Configuring the X Server</a></span></dt><dt><span class="section"><a href="#id314642">Choosing a Window Manager</a></span></dt><dt><span class="section"><a href="#id351028">Setting Up A Graphical Login</a></span></dt></dl></div><div class="section" title="What Is (And Isn't) X"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id358884"></a>What Is (And Isn't) X</h2></div></div></div><p> +Eons ago computer terminals came with a screen and a keyboard and not +much else. Mice hadn't come into common use and everything was menu +driven. Then came the Graphical User Interface (GUI) and the world was +changed. Today users are accustomed to moving a mouse around a screen, +clicking on icons and running tasks with fancy images and animation, +but UNIX systems predated this and so GUIs were added almost as an +afterthought. For many years, Linux and its UNIX brethren were +primarily used without graphics of any sort, but today it is perhaps +more common than not for users to prefer their Linux computers come +with shiney, flashy, clickable GUIs, and all these GUIs run on +<span class="application">X</span>(7). +</p><p> +So what is X? Is it the desktop with the icons? Is it the menus? Is it +the window manager? Does it mark the spot? The answer to all these is a +resounding "no". There are many parts to a GUI, but X is the most +fundamental. X is that application that receives input from the mouse, +keyboard, and possibly other devices. X is that application that tells +the graphics card what to do. In short, X is the application that talks +to your computer's hardware from graphical purposes; all other +graphical applications simply talk to X. +</p><p> +Let's stop for a moment and talk about nomenclature. X is just one of a +dozen names that you may encounter. It is also called X11, the X Window +System, X Window, X11R6, X Version 11, and several others. Whatever +you hear it called, simply understand that the speakers are referring +to X. +</p></div><div class="section" title="Configuring the X Server"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id320754"></a>Configuring the X Server</h2></div></div></div><p> +As powerful as Slackware Linux is, configuring X can be daunting and +is often one of the first real challenges a new user faces. Don't be +overly concerned if you find this a bit difficult. While many changes +have been made over the years that make this much easier, there are +still computers out there that don't properly auto-detect, or you'll +wish to make some change to some setting and it might not be immediately +apparent what to do. Just remember that when I started using X, it was +far more primitive than it is today, took far more work to configure, +and often crashed without telling the user what was wrong. If I and +thousands of others got this working back then, you can do it today. +Fortunately, Slackware includes a default configuration file that works +for most computers by using the VESA standard. This offers only the +most basic functions and may not allow your graphics card to operate at +its full potential. You may be limited to low resolutions, fewer +colors, and <span class="application">X</span> will be slower. Still, this is +an option for users, particularly those who only want to occassionally +run <span class="application">X</span>. You can try it out now simply by +running <span class="application">startx</span>(1) from a command prompt. +</p><p> +There are many ways to configure <span class="application">X</span>, but the +easiest is to use <span class="application">xorgsetup</span>. This will attempt +to probe probe your computer's hardware and write a working xorg.conf +file. This option is not garaunteed to work; there are some platforms +that it is known not to work with, and there are probably others as +well. Still, it is worth trying first as it is the quickest and least +complicated for a new user to attempt. +</p><p> +The second most popular way to configure <span class="application">X</span> +on your system is the handy <span class="application">xorgconfig</span>(1). +This application asks you a series of questions about your computer's +hardware and writes out a config file based on your choices. Unless you +know exactly what your hardware is, we recommend that you try +<span class="application">xorgsetup</span> first. +</p><p> +Lastly, you can manually configure your <span class="application">X</span> +server by modifying <code class="filename">/etc/X11/xorg.conf</code> with a text +editor. This is not normally a task for the faint of heart, but is +often the easiest way to make minor changes. +</p></div><div class="section" title="Choosing a Window Manager"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id314642"></a>Choosing a Window Manager</h2></div></div></div><p> +Slackware Linux includes many different window managers and desktop +environments. Window managers are the applications responsible for +painting application windows on the screen, resizing these windows, and +similar tasks. Desktop environments include a window manager, but also +add task bars, menus, icons, and more. Slackware includes both the KDE +and XFCE desktop environments and several additional window managers. +Which you use is entirely your own decision, but in general, window +managers tend to be faster than desktop environments and more suitable +to older systems with less memory and slower processors. Desktop +environments will be more comfortable for users accustomed to Microsoft +Windows. +</p><p> +LIST OF DE'S AND WINDOW MANAGERS. +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +FILL THIS IN!!!! +</p><p> +The easiest way to choose a window manager is +<span class="application">xwmconfig</span>(1), included with Slackware Linux. +This application allows a user to choose what window manager to run +with <span class="application">startx</span>. +</p></div><div class="section" title="Setting Up A Graphical Login"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id351028"></a>Setting Up A Graphical Login</h2></div></div></div><p> +By default, when you boot your Slackware Linux system you are presented +with a login prompt on a virtual terminal. This is more than adequate +for most people's needs. If you need to run commandline applications, +you may login and do so right away. If you want to run X, simply executing +<span class="application">startx</span> will do that for you nicely. +But suppose you almost exclusively +use your system for graphical duties like many laptop owners? Wouldn't +it be nice for Slackware to take you straight into a GUI? Fortunately, +there's an easy way to do just that. +</p><p> +Slackware uses the System V init system which allows the administrator +to boot into or change to different runlevels, which are really just +different "states" the computer can be in. In fact, shutting down the +computer is really only a case of changing to a runlevel which +accomplishes just that. Runlevels can be rather complicated, so we +won't delve into them any further than necessary. +</p><p> +Runlevels are configured in <code class="filename">inittab</code>(5). +The most common ones are +runlevel 3 (Slackware's default) and runlevel 4 (GUI). In order to tell +Slackware to boot to a GUI screen, simply open +<code class="filename">/etc/inittab</code> with your +favorite editor of choice. (You may wish to refer to one of the +chapters on <span class="application">vi</span> or +<span class="application">emacs</span> at this point.) Near the top, you'll +see the relevant entries. +</p><pre class="screen"> +# These are the default runlevels in Slackware: +# 0 = halt +# 1 = single user mode +# 2 = unused (but configured the same as runlevel 3) +# 3 = multiuser mode (default Slackware runlevel) +# 4 = X11 with KDM/GDM/XDM (session managers) +# 5 = unused (but configured the same as runlevel 3) +# 6 = reboot + +# Default runlevel. (Do not set to 0 or 6) +id:3:initdefault: +</pre><p> +In this file (along with most configuration files) anything following a +hash symbol # is a comment and not interpreted by init(8). Don't worry +if you don't understand everything about inittab, as many veteran users +don't either. The only line we are interested in is the last on above. +Simply change the 3 to a 4 and reboot. +</p><pre class="screen"> +# These are the default runlevels in Slackware: +# 0 = halt +# 1 = single user mode +# 2 = unused (but configured the same as runlevel 3) +# 3 = multiuser mode (default Slackware runlevel) +# 4 = X11 with KDM/GDM/XDM (session managers) +# 5 = unused (but configured the same as runlevel 3) +# 6 = reboot + +# Default runlevel. (Do not set to 0 or 6) +id:4:initdefault: +</pre></div></div><div class="chapter" title="Chapter 7. Printing"><div class="titlepage"><div><div><h2 class="title"><a name="id292994"></a>Chapter 7. Printing</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id337782">Choosing A Printer</a></span></dt><dt><span class="section"><a href="#id357050">Setting Up a Printer in CUPS</a></span></dt><dt><span class="section"><a href="#id322037">Commandline Printing Tools</a></span></dt></dl></div><div class="section" title="Choosing A Printer"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id337782"></a>Choosing A Printer</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Setting Up a Printer in CUPS"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id357050"></a>Setting Up a Printer in CUPS</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Commandline Printing Tools"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id322037"></a>Commandline Printing Tools</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div></div><div class="chapter" title="Chapter 8. Users and Groups"><div class="titlepage"><div><div><h2 class="title"><a name="id337784"></a>Chapter 8. Users and Groups</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id359209">What Are Users and Groups?</a></span></dt><dt><span class="section"><a href="#id341153">Managing Users and Groups</a></span></dt><dt><span class="section"><a href="#id359270">Other User and Group Tools</a></span></dt><dt><span class="section"><a href="#id321249">Managing Users and Groups Manually</a></span></dt></dl></div><div class="section" title="What Are Users and Groups?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id359209"></a>What Are Users and Groups?</h2></div></div></div><p> +Slackware Linux inherits a strong multi-user tradition from its UNIX +inspiration. This means that multiple people may use the system at +once, but it also means that each of these people may have different +permissions. This allows users to prevent others from modifying their +files, or lets system administrators explicitly define what users can +and cannot do on the system. Moreover, users need not be actual people +at all. In fact, Slackware includes several dozen pre-defined user +and group accounts that are not typically used by regular users. Rather +these accounts allow the system administrator to segment the system for +security reasons. We'll see how that's done in the next chapter on +filesystem permissions. +</p></div><div class="section" title="Managing Users and Groups"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id341153"></a>Managing Users and Groups</h2></div></div></div><p> +The easiest way to add new users in Slackware is through the use of our +very fine <span class="application">adduser</span> shell script. +<span class="application">adduser</span> will prompt you to enter the details +of the new user you wish to creature and step you through the process +quickly and easily. It will even create a password for the new user. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>adduser</code></strong> + +Login name for new user []: <strong class="userinput"><code>david</code></strong> + +User ID ('UID') [ defaults to next available ]: + +Initial group [ users ]: +Additional UNIX groups: + +Users can belong to additional UNIX groups on the system. +For local users using graphical desktop login managers such +as XDM/KDM, users may need to be members of additional groups +to access the full functionality of removable media devices. + +* Security implications * +Please be aware that by adding users to additional groups may +potentially give access to the removable media of other users. + +If you are creating a new user for remote shell access only, +users do not need to belong to any additional groups as standard, +so you may press ENTER at the next prompt. + +Press ENTER to continue without adding any additional groups +Or press the UP arrow to add/select/edit additional groups +: <strong class="userinput"><code>audio cdrom floppy plugdev video</code></strong> + +Home directory [ /home/david ] + +Shell [ /bin/bash ] + +Expiry date (YYYY-MM-DD) []: + +New account will be created as follows: + +--------------------------------------- +Login name.......: david +UID..............: [ Next available ] +Initial group....: users +Additional groups: audio,cdrom,floppy,plugdev,video +Home directory...: /home/david +Shell............: /bin/bash +Expiry date......: [ Never ] + +This is it... if you want to bail out, hit Control-C. Otherwise, press +ENTER to go ahead and make the account. + + +Creating new account... + + +Changing the user information for david +Enter the new value, or press ENTER for the default + Full Name []: + Room Number []: + Work Phone []: + Home Phone []: + Other []: +Changing password for david +Enter the new password (minimum of 5, maximum of 127 characters) +Please use a combination of upper and lower case letters and numbers. +New password: +Re-enter new password: +Password changed. + + +Account setup complete. +</pre><p> +The addition of optional groups needs a little explaining. Every user +in Slackware has a single group that it is always a member of. By +default, this is the "users" group. However, users can belong to more +than one group at a time and will inherit all the permissions of every +group they belong to. Typical desktop users will need to add several +group memberships in order to do things like play sound or access +removeable media like cdroms or USB flash drives. You can simply press +the up arrow key at this section and a list of default groups for +desktop users will magically appear. You can of course, add to or +remove groups from this listing. +</p><p> +Now that we've demonstrated how to use the interactive +<span class="application">adduser</span> program, lets look at some powerful +non-interactive tools that you may wish to use. The first is +<span class="application">useradd</span>(8). +<span class="application">useradd</span> is a little less friendly, but much +faster for creating users in batches. This makes it ideal for use in +shell scripts. In fact, <span class="application">adduser</span> is just such +a shell script and uses <span class="application">useradd</span> for most of +the heavy lifting. <span class="application">useradd</span> has many options +and we can't explain them all here, so refer to its man page for the +complete details. Now, let's make a new user. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>useradd -d /data/home/alan -s /bin/bash -g users -G audio,cdrom,floppy,plugdev,video alan</code></strong> +</pre><p> +Here I have added the user "alan". I specified the user's home +directory as <code class="filename">/data/home/alan</code> and used +<span class="application">bash</span> as my shell. Also, I specified my +default group as "users" and added myself to a number of useful groups +for dekstop use. You'll note that <span class="application">useradd</span> +does not do any prompting like <span class="application">adduser</span>. +Unless you want to accept the defaults for everything, you'll need to +tell <span class="application">useradd</span> what to do. +</p><p> +Now that we know how to add users, we should learn how to add groups. +As you might have guessed, the command for doing this is +<span class="application">groupadd</span>(8). +<span class="application">groupadd</span> works in the same way as +<span class="application">useradd</span>, but with far fewer options. The +following command adds the group "slackers" to the system. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>groupadd slackers</code></strong> +</pre><p> +Deleting users and groups is easy as well. Simply run the +<span class="application">userdel</span>(8) and +<span class="application">groupdel</span>(8) commands. By default, +<span class="application">userdel</span> will leave the user's home directory +on the system. You can remove this with the [-r] argument. +</p></div><div class="section" title="Other User and Group Tools"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id359270"></a>Other User and Group Tools</h2></div></div></div><p> +Several other tools exist for managing users and groups. Perhaps the +most important one is <span class="application">passwd</span>(1). This +command changes a user account's password. Normal users may change +their own passwords only, but root can change anyone's password. Also, +root can lock a user account with the [-l] argument. This +doesn't actually shutout the account, but instead changes the user's +encrypted password to a value that can't be matched. +</p><p> +Another useful tool is <span class="application">chsh</span>(1) which changes a +user's default shell. Like <span class="application">passwd</span>, normal +users can only change their own shell, but the root user can change +anyone's. +</p><p> +The last tool we're going to discuss is +<span class="application">chfn</span>(1). This is used to enter identifying +information on the user such as his phone number and real name. This +information is stored in the <code class="filename">passwd</code>(5) file and +retrieved using <span class="application">finger</span>(1). +</p></div><div class="section" title="Managing Users and Groups Manually"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id321249"></a>Managing Users and Groups Manually</h2></div></div></div><p> +Like most things in Slackware Linux, users and groups are stored in +plain-text files. This means that you can edit all the details of a +user, or even create a new user or group simply by editing these files +and doing a few other tasks like creating the user's home directory. Of +course, after you see how this is done you'll appreciate just how +simple the included tools make this task. +</p><p> +Our first stop is the <code class="filename">/etc/passwd</code> file. Here, all +the information about a user is stored, except for (oddly enough) the +user's password. The reason for this is rather simple. +<code class="filename">/etc/passwd</code> must be readable by all users on the +system, so you wouldn't want passwords stored there, even if they are +encrypted. Let's take a quick look at my entry in this file. +</p><pre class="screen"> +alan:x:1000:100:,,,:/home/alan:/bin/bash +</pre><p> +Each line in this file contains a number of fields seperated by a +colon. They are, from left to right: username, password, UID, GUID, a +comment field, home directory, and shell. You'll notice that the +password field for every entry is an <span class="keycap"><strong>x</strong></span>. That is +because Slackware uses shadow passwords, so the actual encrypted +password is stored in <code class="filename">/etc/shadow</code>. Let's take a +look there. +</p><pre class="screen"> +alan:$1$HlR?M3fkL@oeJmsdLfhsLFM*4dflPh8:14197:0:99999:7::: +</pre><p> +The <code class="filename">shadow</code> file contains more than just the +encrypted password as you'll notice. The fields here, again from left +to right, are: username, encrypted password, last day the password was +changed, days before the password may be changed again, how many days +before the password expires, days that the account will be disabled +after expiring, when the account was disabled, and a reserved field. +You may notice on some accounts that the various "days" fields often +include very large numbers. The reason for this is that Slackware +counts time from the "Epoch" which is January 1, 1970 for historical +reasons. +</p><p> +To create a new user account, you'll just need to open these files +using <span class="application">vipw</span>(8). This will open +<code class="filename">/etc/passwd</code> in the editor +defined by your VISUAL variable or your EDITOR variable if VISUAL isn't +defined. If neither is present, it will fall back to +<span class="application">vi</span> by default. If you pass the [-s] +argument, it will open <code class="filename">/etc/shadow</code> instead. It's +important to use <span class="application">vipw</span> instead of using any +other editor, because <span class="application">vipw</span> will lock the +file and prevent other programs from editing it right underneath your feet. +</p><p> +That isn't all you'll need to do however; you must also create the +user's home directory and change the user's password using +<span class="application">passwd</span>. +</p></div></div><div class="chapter" title="Chapter 9. Filesystem Permissions"><div class="titlepage"><div><div><h2 class="title"><a name="id290832"></a>Chapter 9. Filesystem Permissions</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id312644">Permissions Overview</a></span></dt><dt><span class="section"><a href="#id336783"><span class="application">chmod</span>, +<span class="application">chown</span>, and +<span class="application">chgrp</span></a></span></dt><dt><span class="section"><a href="#id342316">SUID, SGID, and the "Sticky" Bit</a></span></dt></dl></div><div class="section" title="Permissions Overview"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id312644"></a>Permissions Overview</h2></div></div></div><p> +As we've discussed, Slackware Linux is a multi-user operating system. +Because of this, its filesystems are mutli-user as well. This means +that every file or directory has a set of permissions that can grant or +deny privileges to different users. There are three basic permissions +and three sets of permissions for each file. Let's take a look at an +example file. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -l /bin/ls</code></strong> +-rwxr-xr-x 1 root root 81820 2007-06-08 21:12 /bin/ls +</pre><p> +Recall from chapter 4 that <span class="application">ls</span> [-l] +lists the permissions for a file or +directory along with the user and group that "own" the file. In this +case, the permissions are rwxr-xr-x, the user is root and the group is +also root. The permissions section, while grouped together, is really +three seperate pieces. The first set of three letters are the +permissions granted to the user that owns the file. The second set of +three are those granted to the group owner, and the final three are +permissions for everyone else. +</p><div class="table"><a name="id337693"></a><p class="title"><b>Table 9.1. Permissions of /bin/ls</b></p><div class="table-contents"><table summary="Permissions of /bin/ls" border="1"><colgroup><col><col><col></colgroup><thead><tr><th>Set</th><th>Listing</th><th>Meaning</th></tr></thead><tbody><tr><td>Owner</td><td>rwx</td><td>The owner "root" may read, write, and execute</td></tr><tr><td>Group</td><td>r-x</td><td>The group "root" may read and execute</td></tr><tr><td>Others</td><td>r-x</td><td>Everyone else may read and execute</td></tr></tbody></table></div></div><br class="table-break"><p> +The permissions are pretty self explainatory of course, at least for +files. Read, write, and execute allow you to read a file, write to it, +or execute it. But what do these permissions mean for directories? +Simply put, the read permissions grants the ability to list the +directory's contents (say with <span class="application">ls</span>). The write +permission grants the ability to create new files in the directory as +well as delete the entire directory, even if you otherwise wouldn't be +able to delete some of the other files inside it. The execute +permission grants the ability to actually enter the directory (with the +<span class="application">bash</span> built-in command cd for example). +</p><p> +Let's look at the permissions on a directory now. +</p><pre class="screen"><code class="prompt">darkstar:~$ </code><strong class="userinput"><code>ls -ld /home/alan</code></strong> +drwxr-x--- 60 alan users 3040 2008-06-06 17:14 /home/alan/ +</pre><p> +Here we see the permissions on my home directory and its ownership. The +directory is owned by the user alan and the group users. The user is +granted all rights (rwx), the group is granted only read and execute +permissions (r-x), and everyone else is prohibited from doing anything. +</p></div><div class="section" title="chmod, chown, and chgrp"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id336783"></a><span class="application">chmod</span>, +<span class="application">chown</span>, and +<span class="application">chgrp</span></h2></div></div></div><p> +So now that we know what permissions are, how do we change them? And +for that matter, how do we assign user and group ownership? The answer +is right here in this section. +</p><p> +The first tool we'll discuss is the useful +<span class="application">chown</span> +(1) command. Using <span class="application">chown</span>, we can (you guessed +it), change the ownership of a file or +directory. <span class="application">chown</span> is historically used only +to change the user ownership, but can change the group ownership as well. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /tmp/foo</code></strong> +total 0 +-rw-r--r-- 1 alan users 0 2008-06-06 22:29 a +-rw-r--r-- 1 alan users 0 2008-06-06 22:29 b +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>chown root /tmp/foo/a</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /tmp/foo</code></strong> +total 0 +-rw-r--r-- 1 root users 0 2008-06-06 22:29 a +-rw-r--r-- 1 alan users 0 2008-06-06 22:29 b +</pre><p> +By using a colon after the user account, you may also specify a new +group account. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chown root:root /tmp/foo/b</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code> ls -l /tmp/foo</code></strong> +total 0 +-rw-r--r-- 1 root users 0 2008-06-06 22:29 a +-rw-r--r-- 1 root root 0 2008-06-06 22:29 b +</pre><p> +<span class="application">chown</span> can also be used recursively to change +the ownership of all files and directories below a target directory. +The following command would change all the files under the directory +<code class="filename">/tmp/foo</code> to have their ownership set to root:root. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chown -R root:root /tmp/foo/b</code></strong></pre><p> +Specifying a colon and a group name without a user name will simply +change the group for a file and leave the user ownership intact. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chown :wheel /tmp/foo/a</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /tmp/foo</code></strong> +ls -l /tmp/foo +total 0 +-rw-r--r-- 1 root wheel 0 2008-06-06 22:29 a +-rw-r--r-- 1 root root 0 2008-06-06 22:29 b +</pre><p> +The younger brother of <span class="application">chown</span> is the +slightly less useful <span class="application">chgrp</span>(1). This +command works just like <span class="application">chown</span>, except +it can only change the group +ownership of a file. Since <span class="application">chown</span> can +already do this, why bother with +<span class="application">chgrp</span>? The answer is simple. Many other +operating systems use a +different version of <span class="application">chown</span> that cannot +change the group ownership, so +if you ever come across one of those, now you know how. +</p><p> +There's a reason we discussed changing ownership before changing +permissions. The first is a much easier concept to grasp. The tool for +changing permissions on a file or directory is +<span class="application">chmod</span>(1). The syntax for it +is nearly identical to that for <span class="application">chown</span>, but +rather than +specify a user or group, the administrator must specify either a set of +octal permissions or a set of alphabetic permissions. Neither one is +especially easy to grasp the first time. We'll begin with the less +complicated octal permissions. +</p><p> +Octal permissions derive their name from being assigned by one of eight +digits, namely the numbers 0 through 7. Each permissions is assigned a +number that is a power of 2, and those numbers are added together to +get the final permissions for one of the permission sets. If this +sounds confusing, maybe this table will help. +</p><div class="table"><a name="id330724"></a><p class="title"><b>Table 9.2. Octal Permissions</b></p><div class="table-contents"><table summary="Octal Permissions" border="1"><colgroup><col><col></colgroup><thead><tr><th>Permission</th><th>Meaning</th></tr></thead><tbody><tr><td>Read</td><td>4</td></tr><tr><td>Write</td><td>2</td></tr><tr><td>Execute</td><td>1</td></tr></tbody></table></div></div><br class="table-break"><p> +By adding these values together, we can reach any number between 0 and +7 and specify all possible permission combinations. For example, to +grant both read and write privilages while denying execute, we would +use the number 6. The number 3 would grant write and execute +permissions, but deny the ability to read the file. We must specify a +number for each of the three sets when using octal permissions. It's +not possible to specify only a set of user or group permissions this +way for example. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /tmp/foo/a</code></strong> +-rw-r--r-- 1 root root 0 2008-06-06 22:29 a +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod 750 /tmp/foo/a</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /tmp/foo/a</code></strong> +-rwxr-x--- 1 root root 0 2008-06-06 22:29 a +</pre><p> +<span class="application">chmod</span> can also use letter values along with +<span class="keycap"><strong>+</strong></span> or <span class="keycap"><strong>-</strong></span> to grant or deny permissions. +While this may be easier to +remember, it's often easier to use the octal permissions. +</p><div class="table"><a name="id342090"></a><p class="title"><b>Table 9.3. Alphabetic Permissions</b></p><div class="table-contents"><table summary="Alphabetic Permissions" border="1"><colgroup><col><col></colgroup><thead><tr><th>Permission</th><th>Letter Value</th></tr></thead><tbody><tr><td>Read</td><td>r</td></tr><tr><td>Write</td><td>w</td></tr><tr><td>Execute</td><td>x</td></tr></tbody></table></div></div><br class="table-break"><div class="table"><a name="id342158"></a><p class="title"><b>Table 9.4. Alphabetic Users and Groups</b></p><div class="table-contents"><table summary="Alphabetic Users and Groups" border="1"><colgroup><col><col></colgroup><thead><tr><th>Accounts Affected</th><th>Letter Value</th></tr></thead><tbody><tr><td>User/Owner</td><td>u</td></tr><tr><td>Group</td><td>g</td></tr><tr><td>Others/World</td><td>o</td></tr></tbody></table></div></div><br class="table-break"><p> +To use the letter values with <span class="application">chmod</span>, you +must specify which set to use them with, either "u" for user, "g" for +group, and "o" for all others. You must also specify whether you are +adding or removing permissions with the "+" and "-" signs. Multiple +sets can be changed at once by seperating each with a comma. +</p><pre class="screen"><code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>ls -l</code></strong> +total 0 +-rw-r--r-- 1 alan users 0 2008-06-06 23:37 a +-rw-r--r-- 1 alan users 0 2008-06-06 23:37 b +-rw-r--r-- 1 alan users 0 2008-06-06 23:37 c +-rw-r--r-- 1 alan users 0 2008-06-06 23:37 d +<code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>chmod u+x a</code></strong> +<code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>chmod g+w b</code></strong> +<code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>chmod u+x,g+x,o-r c</code></strong> +<code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>chmod u+rx-w,g+r,o-r d</code></strong> +<code class="prompt">darkstar:/tmp/foo# </code><strong class="userinput"><code>ls -l</code></strong> +-rwxr--r-- 1 alan users 0 2008-06-06 23:37 a* +-rw-rw-r-- 1 alan users 0 2008-06-06 23:37 b +-rwxr-x--- 1 alan users 0 2008-06-06 23:37 c* +-r-xr----- 1 alan users 0 2008-06-06 23:37 d* +</pre><p> +Which you prefer to use is entirely up to you. There are places where +one is better than the other, so a real Slacker will know both inside +out. +</p></div><div class="section" title='SUID, SGID, and the "Sticky" Bit'><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id342316"></a>SUID, SGID, and the "Sticky" Bit</h2></div></div></div><p> +We're not quite done with permissions just yet. There are three other +"special" permissions in addition to those mentioned above. They are +SUID, SGID, and the sticky bit. When a file has one or more of these +permissions set, it behaves in special ways. The SUID and SGID +permissions change the way an application is run, while the sticky bit +restricts deletion of files. These permissions are applied with +<span class="application">chmod</span> +like read, write, and execute, but with a twist. +</p><p> +SUID and SGID stand for "Set User ID" and "Set Group ID" respectively. +When an application with one of these bits is set, the application runs +with the user or group ownership permissions of that application +regardless of what user actually +executed it. Let's take a look at a common SUID application, the humble +<span class="application">passwd</span> and the files it modifies. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -l /usr/bin/passwd \ + /etc/passwd \ + /etc/shadow</code></strong> +-rw-r--r-- 1 root root 1106 2008-06-03 22:23 /etc/passwd +-rw-r----- 1 root shadow 627 2008-06-03 22:22 /etc/shadow +-rws--x--x 1 root root 34844 2008-03-24 16:11 /usr/bin/passwd* +</pre><p> +Notice the permissions on <span class="application">passwd</span>. Instead of +an <span class="keycap"><strong>x</strong></span> in the user's execute slot, we have an +<span class="keycap"><strong>s</strong></span>. This tells us that +<span class="application">passwd</span> is a SUID program, and when we run +it, the process will run as the user "root" rather than as the user +that actually executed it. The reason for this is readily apparent as +soon as you look at the two files it modifies. Neither +<code class="filename">/etc/passwd</code> nor <code class="filename">/etc/shadow</code> +are writeable by anyone other than root. Since users need to change +their personal information, <span class="application">passwd</span> must be +run as root in order to modify those files. +</p><p> +So what about the sticky bit? The sticky bit restricts the ability to +move or delete files and is only ever set on directories. Non-root +users cannot move or delete any files under a directory with the sticky +bit set unless they are the owner of that file. Normally anyone with +write permission to the file can do this, but the sticky bit prevents +it for anyone but the owner (and of course, root). Let's take a look at +a common "sticky" directory. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ls -ld /tmp</code></strong> +drwxrwxrwt 1 root root 34844 2008-03-24 16:11 /tmp +</pre><p> +Naturally, being a directory for the storage of temporary files sytem +wide, <code class="filename">/tmp</code> needs to be readable, writeable, and +executable by anyone and everyone. Since any user is likely to have a +file or two stored here at any time, it only makes good sense to +prevent other users from deleting those files, so the sticky bit has +been set. You can see it by the presence of the <span class="keycap"><strong>t</strong></span> in +place of the <span class="keycap"><strong>x</strong></span> in the world permissions section. +</p><div class="table"><a name="id342457"></a><p class="title"><b>Table 9.5. SUID, SGID, and "Sticky" Permissions</b></p><div class="table-contents"><table summary='SUID, SGID, and "Sticky" Permissions' border="1"><colgroup><col><col><col></colgroup><thead><tr><th>Permission Type</th><th>Octal Value</th><th>Letter Value</th></tr></thead><tbody><tr><td>SUID</td><td>4</td><td>s</td></tr><tr><td>SGID</td><td>2</td><td>s</td></tr><tr><td>Sticky</td><td>1</td><td>t</td></tr></tbody></table></div></div><br class="table-break"><p> +When using octal permissions, you must specify an additional leading +octal value. For example, to recreate the permission on +<code class="filename">/tmp</code>, we would use 1777. To recreate those +permissions on <code class="filename">/usr/bin/passwd</code>, we would use 4711. +Essentially, any time this leading fourth octet isn't specified, +<span class="application">chmod</span> assumes its value to be 0. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod 1777 /tmp</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod 4711 /usr/bin/passwd</code></strong> +</pre><p> +Using the alphabetic permission values is slightly different. Assuming +the two files above have permissions of 0000 (no permissions at all), +here is how we would set them. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod ug+rwx,o+rwt /tmp</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod u+rws,go+x /usr/bin/passwd</code></strong> +</pre></div></div><div class="chapter" title="Chapter 10. Working with Filesystems"><div class="titlepage"><div><div><h2 class="title"><a name="id283108"></a>Chapter 10. Working with Filesystems</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id325517">The Filesystem Hierarchy</a></span></dt><dt><span class="section"><a href="#id318597">Local Filesystem Types</a></span></dt><dd><dl><dt><span class="section"><a href="#id318610">ext2</a></span></dt><dt><span class="section"><a href="#id318624">ext3</a></span></dt><dt><span class="section"><a href="#id318642">reiserfs</a></span></dt><dt><span class="section"><a href="#id318656">XFS</a></span></dt><dt><span class="section"><a href="#id318671">JFS</a></span></dt><dt><span class="section"><a href="#id318685">iso9660</a></span></dt><dt><span class="section"><a href="#id318711">vfat</a></span></dt><dt><span class="section"><a href="#id355976">swap</a></span></dt></dl></dd><dt><span class="section"><a href="#id355992">Using <span class="application">mount</span></a></span></dt><dt><span class="section"><a href="#id360747">Network Filesystems</a></span></dt><dd><dl><dt><span class="section"><a href="#id360758">NFS</a></span></dt><dt><span class="section"><a href="#id360899">SMB</a></span></dt></dl></dd></dl></div><div class="section" title="The Filesystem Hierarchy"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id325517"></a>The Filesystem Hierarchy</h2></div></div></div><p> +Slackware Linux stores all of its files and directories under a single +<code class="filename">/</code> directory, typically referred to as "root". This +is in stark contract to what you may be familiar with in the form of +Microsoft Windows. Different hard disk partitions, cdroms, usb flash +drives, and even floppy disks can all be mounted in directories under +<code class="filename">/</code>, but do not have anything like "drive letters". +The contents of these devices can be found almost anywhere, but there +are some sane defaults that Slackware sets up for you. For example, +cd-rw drives are most often found at <code class="filename">/mnt/cd-rw</code>. +Here are a few common directories present on nearly all Slackware Linux +installations, and what you can expect to find there. +</p><div class="table"><a name="id336627"></a><p class="title"><b>Table 10.1. Filesystem Layout</b></p><div class="table-contents"><table summary="Filesystem Layout" border="1"><colgroup><col><col></colgroup><thead></thead><tbody><tr><td>/</td><td>The root directory, under which all others exist</td></tr><tr><td>/bin</td><td>Minimal set of binary programs for all users</td></tr><tr><td>/boot</td><td>The kernel, initrd, and other requirements for booting Slackware</td></tr><tr><td>/etc/</td><td>System configuration files</td></tr><tr><td>/dev</td><td>Collection of special files allowing direct access to hardware</td></tr><tr><td>/home</td><td>User directories where personal files and settings are stored</td></tr><tr><td>/media</td><td>Directory for auto-mounting features in DBUS/HAL</td></tr><tr><td>/mnt</td><td>Places to temporarily mount removable media</td></tr><tr><td>/opt</td><td>Directory where some (typicaly proprietary) software may be installed</td></tr><tr><td>/proc</td><td>Kernel exported filesystem for process information</td></tr><tr><td>/root</td><td>The root user's home directory</td></tr><tr><td>/sbin</td><td>Minimal set of system or superuser binaries</td></tr><tr><td>/srv</td><td>Site-specific data such as web pages served by this system</td></tr><tr><td>/sys</td><td>Special kernel implimentation details</td></tr><tr><td>/tmp</td><td>Directory reserved for temporary files for all users</td></tr><tr><td>/usr</td><td>All non-essential programs, libraries, and shared files</td></tr><tr><td>/var</td><td>Regularly changing data such as log files</td></tr></tbody></table></div></div><br class="table-break"></div><div class="section" title="Local Filesystem Types"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id318597"></a>Local Filesystem Types</h2></div></div></div><p> +The Linux kernel supports a wide variety of filesystems, which allows +you to choose from a long list of features to tailor to your particular +need. Fortunately, most of the default filesystem types are adequate +for any needs you may have. Some filesystems are geared towards +particular media. For example, the iso9660 filesystem is used almost +exclusively for CD and DVD media. +</p><div class="section" title="ext2"><div class="titlepage"><div><div><h3 class="title"><a name="id318610"></a>ext2</h3></div></div></div><p> +ext2 is the oldest filesystem included in Slackware Linux for storing +data on hard disks. Compared to other filesystems, ext2 is simplistic. +It is faster than most others for reading and writing data, but does +not include any journaling capability. This means that after a hard +crash, the filesystem must be exhaustively checked to discover and +(hopefully) fix any errors. +</p></div><div class="section" title="ext3"><div class="titlepage"><div><div><h3 class="title"><a name="id318624"></a>ext3</h3></div></div></div><p> +ext3 is the younger cousin of ext2. It was designed to replace ext2 in +most situations and shares much the same code-base, but adds journaling +support. In fact, ext3 and ext2 are so much alike that it is possible +to convert one to the other on the fly without lose of data. ext3 +enjoys a lot of popularity for these reasons. There are many tools +available for recovering data from this filesystem in the event of +catastrophic hardware failure as well. ext3 is a good general purpose +filesystem with journaling support, but fails to perform as well as +other journaling filesystems in specific cases. One pitfall to ext3 is +that the filesystem must still go through this exhaustive check every +so often. This is done when the filesystem is mounted, usually when the +computer is booted, and causes an annoying delay. +</p></div><div class="section" title="reiserfs"><div class="titlepage"><div><div><h3 class="title"><a name="id318642"></a>reiserfs</h3></div></div></div><p> +reiserfs is one of the oldest journaling filesystems for the Linux +kernel and has been supported by Slackware for many years. It is a very +fast filesystem particularly well suited for storing, retrieving, and +writing lots of small files. Unfortunately there are few tools for +recovering data should you experience a drive failure, and reiserfs +partitions experience corruption more often than ext3. +</p></div><div class="section" title="XFS"><div class="titlepage"><div><div><h3 class="title"><a name="id318656"></a>XFS</h3></div></div></div><p> +XFS was contributed to the Linux kernel by SGI and is one of the best +filesystems for working with large volumes and large files. XFS uses +more RAM than other filesystems, but if you need to work with large +files its performance there is well worth the penalty in memory usage. +XFS is not particularly ill-suited for desktop or laptop use, but +really shines on a server that handles medium to large size files all +day long. Like ext3, XFS is a fully journaled filesystem. +</p></div><div class="section" title="JFS"><div class="titlepage"><div><div><h3 class="title"><a name="id318671"></a>JFS</h3></div></div></div><p> +JFS was contributed to the Linux kernel by IBM and is well known for +its responsiveness even under extreme conditions. It can span colossal +volumes making it particularly well-suited for Network Attached Storage +(NAS) devices. JFS's long history and thorough testing make it one of +the most reliable journaling filesystems available for Linux. +</p></div><div class="section" title="iso9660"><div class="titlepage"><div><div><h3 class="title"><a name="id318685"></a>iso9660</h3></div></div></div><p> +iso9660 is a filesystem specifically designed for optical media such as +CDs and DVDs. Since optical disks are read-only media, the linux kernel +does not even include write support for this filesystem. In order to +create an iso9660 filesystem, you must use user-land tools like +<span class="application">mkisofs</span>(8) or +<span class="application">growisofs</span>(8). +</p></div><div class="section" title="vfat"><div class="titlepage"><div><div><h3 class="title"><a name="id318711"></a>vfat</h3></div></div></div><p> +Sometimes you may need to share data between Windows and Linux +computers, but can't transfer the files over a network. Instead you +require a shared hard drive partition or a USB flash drive. The humble +vfat filesystem is the best choice here since it is supported by the +largest variety of operating systems. Unfortuantely, being a Microsoft +designed filesystem, it does not store permissions in the same way as +traditional Linux filesystems. This means that special options must be +used to allow multiple users to access data on this filesystem. +</p></div><div class="section" title="swap"><div class="titlepage"><div><div><h3 class="title"><a name="id355976"></a>swap</h3></div></div></div><p> +Unlike other filesystems which hold files and directories, swap +partitions hold virtual memory. This is very useful as it prevents the +system from crashing should all your RAM be consumed. Instead, the +kernel copies portions of the RAM into swap and frees them up for other +applications to use. Think of it as adding virtual memory to your +computer, very slow virtual memory. swap is typically a fail-safe and +shouldn't be relied upon for continual use. Add more RAM to your system +if you find yourself using lots of swap. +</p></div></div><div class="section" title="Using mount"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id355992"></a>Using <span class="application">mount</span></h2></div></div></div><p> +Now that we've learned what (some of) the different filesystems +available in Linux are, it's time we looked at how to use them. In +order to read or write data on a filesystem, that filesystem must first +be mounted. To do this, we (naturally) use +<span class="application">mount</span>(8). The first thing we must do is +decide where we want the filesystem located. Recall that there are no +such things are drive letters denoting filesystems in Linux. Instead, +all filesystems are mounted on directories. The base filesystem on +which you install Slackware is always located at <code class="filename">/</code> +and others are always located in subdirectories of +<code class="filename">/</code>. <code class="filename">/mnt/hd</code> is a common place +to temporarily locate a partition, so we'll use that in our first +example. In order to mount a filesystem's contents, we must tell mount +what kind of filesystem we have, where to mount it, and any special +options to use. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount -t ext3 /dev/hda3 /mnt/hd -o ro</code></strong> +</pre><p> +Let's disect this. We have an ext3 filesystem located on the third +partition of the first IDE device, and we've decided to mount its +contents on the directory <code class="filename">/mnt/hd</code>. Additionally, +we have mounted it read-only so no changes can be made to these +contents. The [-t ext3] argument tells +<span class="application">mount</span> +what type of filesystem we are using, +in this case it is ext3. This lets the kernel know which driver to use. +Often <span class="application">mount</span> can determine this for itself, +but it never hurts to explicitly declare it. Second, we tell +<span class="application">mount</span> +where to locate the filesystem's contents. Here we've chosen +<code class="filename">/mnt/hd</code>. +Finally, we must decide what options to use if any. These are declared +with the [-o] argument. A short-list of the most common +options follows. +</p><div class="table"><a name="id356105"></a><p class="title"><b>Table 10.2. Common mount options</b></p><div class="table-contents"><table summary="Common mount options" border="1"><colgroup><col><col></colgroup><thead></thead><tbody><tr><td>ro</td><td>read-only</td></tr><tr><td>rw</td><td>read-write (default)</td></tr><tr><td>uid</td><td>user to own the contents of the filesystem</td></tr><tr><td>gid</td><td>group to own the contents of the filesystem</td></tr><tr><td>noexec</td><td>prevent execution of any files on the filesystem</td></tr><tr><td>defaults</td><td>sane defaults for most filesystems</td></tr></tbody></table></div></div><br class="table-break"><p> +If this is your first Linux installation, the only options you +typically need to be concerned about are [ro] and + [rw]. The exception to this rule comes when you are dealing +with filesystems that don't handle traditional Linux permissions such +as vfat or NTFS. In those cases you'll need to use the [uid] +or [gid] options to allow non-root users access to these +filesystems. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount -t vfat /dev/hda4 /mnt/hd -o uid=alan</code></strong> +</pre><p> +But Alan, that's appalling! I don't want to have to tell mount what +filesystem or options to use everytime I load a CD. It should be easier +than that. Well thankfully, it is. The <code class="filename">/etc/fstab</code> +file contains all this information for filesystems that the installer +sets up for you, and you can make additions to it as well. +<code class="filename">fstab</code>(5) looks like a simple table containing the +device to mount along with its filesystem type and optional arguments. +Let's take a look. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>cat /etc/fstab</code></strong> +/dev/hda1 / reiserfs defaults 1 1 +/dev/hda2 /home reiserfs defaults 1 2 +/dev/hda3 swap swap defaults 0 0 +/dev/cdrom /mnt/cdrom auto noauto,owner,ro,users 0 0 +/dev/fd0 /mnt/floppy auto noauto,owner 0 0 +devpts /dev/pts devpts gid=5,mode=620 0 0 +proc /proc proc defaults 0 0 +</pre><p> +If you have an entry in <code class="filename">fstab</code> for your filesystem, you +need only tell mount the device node or the mount location. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount /dev/cdrom</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount /home</code></strong> +</pre><p> +One final use for +<span class="application">mount</span> +is to tell you what filesystems are currently mounted and with what +options. Simply run +<span class="application">mount</span> +without any arguments to display these. +</p></div><div class="section" title="Network Filesystems"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id360747"></a>Network Filesystems</h2></div></div></div><p> +In addition to local filesystems, Slackware supports a number of network +filesystems as both client and server. This allows you to share data +between multiple computers transparently. We'll discuss the two most +common: NFS and SMB. +</p><div class="section" title="NFS"><div class="titlepage"><div><div><h3 class="title"><a name="id360758"></a>NFS</h3></div></div></div><p> +NFS is the Network File System for Linux as well as several other common +operating systems. It has modest performance but supports the full range of +permissions for Slackware. In order to use NFS as either a client or a +server, you must run the remote procedure call daemon. This is easily +accomplished by setting the <code class="filename">/etc/rc.d/rc.rpc</code> file +executable and telling it to start. Once it has been set executable, it +will run automatically every time you boot into Slackware. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>chmod +x /etc/rc.d/rc.rpc</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>/etc/rc.d/rc.rpc start</code></strong> +</pre><p> +Mounting an NFS share is little different than mounting a local filesystem. +Rather than specifying a local device, you must tell mount the domain name +or IP address of the NFS server and the directory to mount with a colon +between them. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount -t nfs darkstar.example.com:/home /home</code></strong> +</pre><p> +Running an NFS server is a little bit different. First, you must configure +each directory to be exported in the <code class="filename">/etc/exports</code> +file. <code class="filename">exports</code>(5) contains information about what +directories will be shared, who they will be shared with, and what special +permissions to grant or deny. +</p><pre class="screen"> +# See exports(5) for a description. +# This file contains a list of all directories exported to other computers. +# It is used by rpc.nfsd and rpc.mountd. + +/home/backup 192.168.1.0/24(sync,rw,no_root_squash) +</pre><p> +The first column in +<code class="filename">exports</code> +is a list of the files to be exported via NFS. The second column is a list +of what systems may access the export along with special permissions. You +can specify hosts via domain name, IP address, or netblock address (as I +have here). Special permissions are always a parenthetical list. For a +complete list, you'll need to read the man page. For now, the only special +option that matters is [no_root_squash]. Usually the root user on +an NFS client cannot read or write an exported share. Instead, the root +user is "squashed" and forced to act as the nobody user. + [no_root_squash] prevents this. +</p><p> +You'll also need to run the NFS daemon. Starting and stopping NFS server +support is done with the <code class="filename">/etc/rc.d/rc.nfsd</code> rc script. +Set it executable and run it just like we did for +<code class="filename">rc.rpc</code> and you are ready to go. +</p></div><div class="section" title="SMB"><div class="titlepage"><div><div><h3 class="title"><a name="id360899"></a>SMB</h3></div></div></div><p> +SMB is the Windows network file-sharing protocol. Connecting to SMB shares +(commonly called samba shares) is fairly straight forward. Unfortuantely, +SMB isn't as strongly supported as NFS. Still, it offers higher performance +and connectivity with Windows computers. For these reasons, SMB is the most +common network file-sharing protocol deployed on local networks. Exporting +SMB shares from Slackware is done through the samba daemon and configured +in <code class="filename">smb.conf</code>(5). Unfortunately configuring samba as a +service is beyond the scope of this book. Check online for additional +documentation, and as always refer to the man page. +</p><p> +Thankfully mounting an SMB share is easy and works almost exactly like +mounting an NFS share. You must tell mount where to find the server and +what share you wish to access in exactly the same way. Additionally, you +must specify a username and password. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount -t cifs //darkstar/home /home -o username=alan,password=secret</code></strong> +</pre><p> +You may be wondering why the filesystem type is cifs instead of smbfs. In +older versions of the Linux kernel, smbfs was used. This has been +deprecated in favor of the better performing and more secure general +purpose cifs driver. +</p><p> +All SMB shares require the [username] and [password] +arguments. This can create a security problem if you wish to place your +samba share in fstab. You may avoid this problem by using the + [credentials] argument. [credentials] points to a file +which contains the username and password information. As long as this file +is safely guarded and readable only by root, the likelyhood that your +authentication credentials will be compromised is lessened. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>echo "username=alan" > /etc/creds-home</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>echo "password=secret" >> /etc/creds-home</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>mount -t cifs //darkstar/home -o credentials=/etc/creds-home</code></strong> +</pre></div></div></div><div class="chapter" title="Chapter 11. vi"><div class="titlepage"><div><div><h2 class="title"><a name="id282063"></a>Chapter 11. <span class="application">vi</span></h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id352102">What is <span class="application">vi</span>?</a></span></dt><dt><span class="section"><a href="#id314220">The Different Modes of <span class="application">vi</span></a></span></dt><dt><span class="section"><a href="#id317601">Opening, Saving, and Quitting</a></span></dt><dt><span class="section"><a href="#id320876">Moving Around</a></span></dt><dt><span class="section"><a href="#id342976">Editing A Document</a></span></dt><dt><span class="section"><a href="#id343009"><span class="application">vi</span> Cheat Sheet</a></span></dt></dl></div><div class="section" title="What is vi?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id352102"></a>What is <span class="application">vi</span>?</h2></div></div></div><p> +Scattered all around your computer are thousands of text files. To a +new user, this may seem inconsequential, but almost everything in +Slackware Linux uses a plain-text file for configuration. This allows +users to make changes to the system quickly, easily, and intuitively. +In chapter 5, we looked at a few commands such as +<span class="application">cat</span> and <span class="application">less</span> that +can be used to read these files, but what if we want to make changes to +them? For that, we need a text editor, and +<span class="application">vi</span> is up to the task. +</p><p> +In short, <span class="application">vi</span> is one of the oldest and most +powerful text editors still used today. It's beloved by system +administrators, programmers, hobbiests, and others the world over. In +fact, nearly this entire book was written using +<span class="application">vi</span>; only the next chapter on +<span class="application">emacs</span> was written with that editor. +</p><p> +A little further explanation is needed to learn exactly what +<span class="application">vi</span> is today though, as Slackware Linux +technically doesn't include <span class="application">vi</span>. Rather, +Slackware includes two vi "clones", <span class="application">elvis</span>(1) +and <span class="application">vim</span>(1). These clones add many additional +features to vi such as syntax highlighting, binary editing modes, and +network support. We won't go too deeply into all these details. By +default, if you execute <span class="application">vi</span> on Slackware +Linux, you'll be using <span class="application">elvis</span>, so all +examples in this chapter will assume that is what you are using. If +you've used another Linux distribution before, you may be more familiar +with <span class="application">vim</span>. If so, you might wish to change +the symlink for <code class="filename">/usr/bin/vi</code> to point to +<code class="filename">/usr/bin/vim</code>, or add an alias to your shell's +startup scripts. <span class="application">vim</span> is generally considered +to be more feature-rich than <span class="application">elvis</span>, but +<span class="application">elvis</span> is a much smaller program and contains +more features than most users will ever need. +</p><p> +<span class="application">vi</span> is very powerful, but also somewhat +cumbersome and challening for a new user to learn. However, mastering +<span class="application">vi</span> is an important skill for any +self-respecting system administrator to learn, as +<span class="application">vi</span> is included on nearly every Linux +distribution, every BSD system, and every UNIX system in existance. +It's even included in Mac OS X. +Once you've learned <span class="application">vi</span>, you'll not have to +learn another text editor to work on any of these systems. In fact, +<span class="application">vi</span> clones have even been ported to Microsoft Windows +systems, so you can use it there too. +</p></div><div class="section" title="The Different Modes of vi"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id314220"></a>The Different Modes of <span class="application">vi</span></h2></div></div></div><p> +New users are often frustrated when using <span class="application">vi</span> +for the first time. When invoked without any arguments, +<span class="application">vi</span> will display a screen something like +this. +</p><pre class="screen"> +~ +~ +~ +~ +~ +~ +~ +~ +~ +~ +~ + Command +</pre><p> +At this point, the user will being typing and expect the keys he +presses to appear in the document. Instead, something really strange +happens. The reason for this is simple. <span class="application">vi</span> +has different operation "modes". There is a command mode and an insert +mode. Command mode is the default; in this mode, each keystroke +performs a particular action such as moving the cursor around, deleting +text, yanking (copying) text, searching, etc. +</p></div><div class="section" title="Opening, Saving, and Quitting"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id317601"></a>Opening, Saving, and Quitting</h2></div></div></div><p> +Ok, so you've decided that you want to learn how to use +<span class="application">vi</span>. The first thing to do is learn how to +open and save files. Opening files is actually pretty easy. Simply type +the filename as an argument on the command-line and +<span class="application">vi</span> will happily load it for you. For +example, <strong class="userinput"><code>vi chapter_11.xml</code></strong> will open the file +<code class="filename">chapter_11.xml</code> and load its content onto the +screen, simple enough. But what if we've finished with one document and +wish to save it? We can do that in command mode using the [:w] +command. When in command mode, pressing the <span class="keycap"><strong>:</strong></span> key +temporarily positions the cursor on the very bottom line of the window +and allows you to enter special commands. (This is technically known as +ex-mode after the venerable <span class="application">ex</span> application +which we will not document here.) The command to save your current work +is [:w]. Once this is done, <span class="application">vi</span> will +write your changes to the buffer back into the file. If you wish to +open another document, simply use the [:e other_document] +command and <span class="application">vi</span> will happily open it for you. +If you've made changes to the buffer but haven't saved it yet, + [:e] will fail and print a warning message on the bottom line. +You can bypass this with the [:e!] command. Most ex-mode +commands in <span class="application">vi</span> can be "forced" by adding +<span class="keycap"><strong>!</strong></span> to them. This tells <span class="application">vi</span> +that you want to abandon any changes you've made to the buffer and open +the other document immediately. +</p><p> +But what if I don't like my changes and want to quit or start over? +That's easily done as well. Executing the [:e!] command +without any arguments will re-open the current document from the +beginning. Quitting <span class="application">vi</span> is as simple as +running the [:q] command if you haven't made any changes to +the buffer, or [:q!] if you'd like to quit and abandon those +changes. +</p></div><div class="section" title="Moving Around"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id320876"></a>Moving Around</h2></div></div></div><p> +Moving around in <span class="application">vi</span> is perhaps the hardest +thing for a new user to learn. <span class="application">vi</span> does not +traditionally use the directional arrow keys for cursor movement, +although in Slackware Linux that is an option. Rather, movement is +simply another command issued in command-mode. The reason for this is +rather simple. <span class="application">vi</span> actually predates the +inclusion of directional arrow keys on keyboards. Thus, +movement of the cursor had to be accomplished by using the few +keys available, so the right-hand "home row" keys of +<span class="keycap"><strong>h</strong></span>, <span class="keycap"><strong>j</strong></span>, <span class="keycap"><strong>k</strong></span>, and +<span class="keycap"><strong>l</strong></span> were chosen. These keys will move the cursor about +whenever <span class="application">vi</span> is in command mode. Here's a +short table to help you remember how they work. +</p><div class="table"><a name="id348996"></a><p class="title"><b>Table 11.1. vi cursor movement</b></p><div class="table-contents"><table summary="vi cursor movement" border="1"><colgroup><col><col></colgroup><thead><tr><th>Command</th><th>Result</th></tr></thead><tbody><tr><td>h</td><td>Move the cursor one character left.</td></tr><tr><td>j</td><td>Move the cursor one line down</td></tr><tr><td>k</td><td>Move the cursor one line up</td></tr><tr><td>l</td><td>Move the cursor one character right</td></tr></tbody></table></div></div><br class="table-break"><p> +Moving around is a little more powerful than that though. Like many +command keys, these movement keys accept numerical arguments. For +example, <span class="keycap"><strong>10j</strong></span> will move the cursor down 10 lines. You +can also move to the end or beginning of the current line with +<span class="keycap"><strong>$</strong></span> and <span class="keycap"><strong>^</strong></span>, respectively. +</p></div><div class="section" title="Editing A Document"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id342976"></a>Editing A Document</h2></div></div></div><p> +Now that we're able to open and save documents, as well as move around +in them, it's time to learn how to edit them. The primary means of +editing is to enter insert mode using either the <span class="keycap"><strong>i</strong></span> or +<span class="keycap"><strong>a</strong></span> command keys. These either insert text at the +cursor's current location, or append it after the cursor's current +location. Once into insert mode, you can type any text normally and it +will be placed into your document. You can return to command mode in +order to save your changes by pressing the <span class="keycap"><strong>ESC</strong></span> key. +</p></div><div class="section" title="vi Cheat Sheet"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id343009"></a><span class="application">vi</span> Cheat Sheet</h2></div></div></div><p> +Since <span class="application">vi</span> can be difficult to learn, I've +prepared a short cheat sheat that should help you with the basics until +you begin to feel comfortable. +</p><div class="table"><a name="id343030"></a><p class="title"><b>Table 11.2. vi Cheat Sheet</b></p><div class="table-contents"><table summary="vi Cheat Sheet" border="1"><colgroup><col><col></colgroup><thead><tr><th>Command</th><th>Result</th></tr></thead><tbody><tr><td>h</td><td>Move the cursor one character left.</td></tr><tr><td>j</td><td>Move the cursor one line down</td></tr><tr><td>k</td><td>Move the cursor one line up</td></tr><tr><td>l</td><td>Move the cursor one character right</td></tr><tr><td>10j</td><td>Move the cursor ten lines down</td></tr><tr><td>G</td><td>Move to the end of the file</td></tr><tr><td>^</td><td>Move to the beginning of the line</td></tr><tr><td>$</td><td>Move to the end of the line</td></tr><tr><td>dd</td><td>Remove a line</td></tr><tr><td>5dd</td><td>Remove 5 lines</td></tr><tr><td>r</td><td>Replace a single character</td></tr><tr><td>R</td><td>Replace multiple characters</td></tr><tr><td>x</td><td>Delete a character</td></tr><tr><td>X</td><td>Delete the previous character</td></tr><tr><td>u</td><td>Undo the last action</td></tr><tr><td>:s'old'new'g</td><td>Replace all occurances of 'old' with 'new'</td></tr><tr><td>/asdf</td><td>Locate next occurance of asdf</td></tr><tr><td>:q</td><td>Quit (without saving)</td></tr><tr><td>:w</td><td>Save the current document</td></tr><tr><td>:w file</td><td>Save the current document as 'file'</td></tr><tr><td>:x</td><td>Save and quit</td></tr></tbody></table></div></div><br class="table-break"></div></div><div class="chapter" title="Chapter 12. Emacs"><div class="titlepage"><div><div><h2 class="title"><a name="id342041"></a>Chapter 12. Emacs</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id317667">No Idea</a></span></dt></dl></div><div class="section" title="No Idea"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id317667"></a>No Idea</h2></div></div></div></div></div><div class="chapter" title="Chapter 13. Networking"><div class="titlepage"><div><div><h2 class="title"><a name="id289613"></a>Chapter 13. Networking</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id328201"><span class="application">netconfig</span></a></span></dt><dt><span class="section"><a href="#id310624">Manual Configuration</a></span></dt><dt><span class="section"><a href="#id319849">Automatic Configuration with rc.inet1.conf</a></span></dt></dl></div><div class="section" title="netconfig"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id328201"></a><span class="application">netconfig</span></h2></div></div></div><p> +Computers aren't very interesting on their own. Sure, you can install +games on them, but that just turns them into glorified entertainment +consoles. Today, computers need to be able to talk to one another; they +need to be networked. Whether you're installing a business network with +hundreds or thousands of computers or just setting up a single PC for +Internet access, Slackware is simple and easy. This chapter should +teach you how to setup typical wired networks. Common wireless setup will +be thoroughly discussed in the next section, but much of what you read +here will be applicable there as well. +</p><p> +There are many different ways to configure your computer to connect to +a network or the Internet, but they fall into two main categories: +static and dymanic. Static addresses are solid; they are set with the +understanding that they will not be changed, at least not anytime soon. +Dynamic addresses are fluid; the assumption is that the address will +change at some time in the future. Typically any sort of network server +requires a static address simply so other machines will know where to +contact it when they need services. Dynamic addresses tend to be used +for workstations, Internet clients, and any machine that doesn't +require a static address for any reason. Dynamic addresses are more +flexible, but present complications of their own. +</p><p> +There are many different kinds of network protocols that you might +encounter, but most people will only ever need to deal with Internet +Protocol (IP). For that reason, we'll focus exclusively on IP in this +book. +</p></div><div class="section" title="Manual Configuration"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id310624"></a>Manual Configuration</h2></div></div></div><p> +Ok, so you've installed Slackware, you've setup a desktop, but you +can't get it to connect to the Internet or your business's LAN (local +area network), what do you do? Fortunately, the answer to that question +is simple. Slackware includes a number of tools to configure your +network connection. The first we will look at today is the very +powerful <span class="application">ifconfig</span>(8). +<span class="application">ifconfig</span> is used to setup or modify the +configuration of a Network Interface Card (NIC or Ethernet Card), the +most common hardware for connecting to networks today. +<span class="application">ifconfig</span> is an incredibly powerful tool +capable of doing much more than setting IP addresses. For a complete +introduction, you should read its man page. For now, we're just going +to use it to display and change the network addresses of some ethernet +controllers. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ifconfig</code></strong> +lo Link encap:Local Loopback + inet addr:127.0.0.1 Mask:255.0.0.0 + inet6 addr: ::1/128 Scope:Host + UP LOOPBACK RUNNING MTU:16436 Metric:1 + RX packets:699 errors:0 dropped:0 overruns:0 frame:0 + TX packets:699 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:0 + RX bytes:39518 (38.5 KiB) TX bytes:39518 (38.5 KiB) + +wlan0 Link encap:Ethernet HWaddr 00:1c:b3:ba:ad:4c + inet addr:192.168.1.198 Bcast:192.168.1.255 Mask:255.255.255.0 + inet6 addr: fe80::21c:b3ff:feba:ad4c/64 Scope:Link + UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 + RX packets:1630677 errors:0 dropped:0 overruns:0 frame:0 + TX packets:1183224 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:1627370207 (1.5 GiB) TX bytes:163308463 (155.7 MiB) + +wmaster0 Link encap:UNSPEC HWaddr 00-1C-B3-BA-AD-4C-00-00-00-00-00-00-00-00-00-00 + UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 + RX packets:0 errors:0 dropped:0 overruns:0 frame:0 + TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) +</pre><p> +As you can clearly see here, when run without any arguments, +<span class="application">ifconfig</span> will display all the information it +has on all the ethernet cards (and wireless ethernet cards) present on +your system. The above represents a typical wireless connection from my +laptop, so don't be afraid if what you see on your system doesn't +match. If you don't see any ethX or wlanX interfaces though, the +interface may be down. To show all currently present NICs whether they are +"up" or "down", simply pass the [-a] argument. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ifconfig -a</code></strong> +eth0 Link encap:Ethernet HWaddr 00:19:e3:45:90:44 + UP BROADCAST MULTICAST MTU:1500 Metric:1 + RX packets:122780 errors:0 dropped:0 overruns:0 frame:0 + TX packets:124347 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:60495452 (57.6 MiB) TX bytes:17185220 (16.3 MiB) + Interrupt:16 + +lo Link encap:Local Loopback + inet addr:127.0.0.1 Mask:255.0.0.0 + inet6 addr: ::1/128 Scope:Host + UP LOOPBACK RUNNING MTU:16436 Metric:1 + RX packets:699 errors:0 dropped:0 overruns:0 frame:0 + TX packets:699 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:0 + RX bytes:39518 (38.5 KiB) TX bytes:39518 (38.5 KiB) + +wlan0 Link encap:Ethernet HWaddr 00:1c:b3:ba:ad:4c + inet addr:192.168.1.198 Bcast:192.168.1.255 Mask:255.255.255.0 + inet6 addr: fe80::21c:b3ff:feba:ad4c/64 Scope:Link + UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 + RX packets:1630677 errors:0 dropped:0 overruns:0 frame:0 + TX packets:1183224 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:1627370207 (1.5 GiB) TX bytes:163308463 (155.7 MiB) + +wmaster0 Link encap:UNSPEC HWaddr 00-1C-B3-BA-AD-4C-00-00-00-00-00-00-00-00-00-00 + UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 + RX packets:0 errors:0 dropped:0 overruns:0 frame:0 + TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) +</pre><p>Notice that the eth0 interface is now listed among the returns. +<span class="application">ifconfig</span> can also change the current +settings on a NIC. Typically, you would need to change the IP address +and subnet mask, but you can change virtually any parameters. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>ifconfig eth0 192.168.1.1 netmask 255.255.255.0</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>ifconfig eth0</code></strong> +eth0 Link encap:Ethernet HWaddr 00:19:e3:45:90:44 + inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0 + UP BROADCAST MULTICAST MTU:1500 Metric:1 + RX packets:122780 errors:0 dropped:0 overruns:0 frame:0 + TX packets:124347 errors:0 dropped:0 overruns:0 carrier:0 + collisions:0 txqueuelen:1000 + RX bytes:60495452 (57.6 MiB) TX bytes:17185220 (16.3 MiB) + Interrupt:16 +</pre><p> +If you look carefully, you'll notice that the interface now has the +192.168.1.1 IP address and a 255.255.255.0 subnet mask. We've now setup +the basics for connecting to our network, but we still need to setup a +default gateway and our DNS servers. In order to do that, we'll need to +look at a few more tools. +</p><p> +Next on our stop through networking land is the equally powerful +<span class="application">route</span>(8). This tool is responsible for +modifying the Linux kernel's routing table which affects all data +transmission on a network. Routing tables can become immensely complex +or they can be straight-forward and simple. Most users will only ever +need to setup a default gateway, so we'll show you how to do that here. +If for some reason you need a more complex routing table, you would be +well advised to read the entire man page for +<span class="application">route</span> as well as consulting other sources. +For now, let's take a look at our routing table immediately after +setting up eth0. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>route</code></strong> +Kernel IP routing table +Destination Gateway Genmask Flags Metric Ref Use Iface +192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 +loopback * 255.0.0.0 U 0 0 0 lo +</pre><p> +I won't explain everything here, but the general information should be +easy to pick up if you're familiar with networking at all. The +Destination and Genmask fields specify a range of IP addresses to +match. If a Gateway is defined, information in the form of packets will +be sent to that host for forwarding. We also specify an interface in +the final field that the information should traverse. Right now, we can +only communicate with computers with addresses between 192.168.1.0 and +192.168.1.255 and ourselves through the loopback interface, a type of +virtual NIC that is used for routing information from this computer to +itself. In order to reach the rest of the world, we'll need to +setup a default gateway. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>route add default gw 192.168.1.254</code></strong> +<code class="prompt">darkstar:~# </code><strong class="userinput"><code>route</code></strong> +Kernel IP routing table +Destination Gateway Genmask Flags Metric Ref Use Iface +192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 +loopback * 255.0.0.0 U 0 0 0 lo +default 192.168.1.254 0.0.0.0 UG 0 0 0 eth0 +</pre><p> +You should immediately notice the addition of a default route. This +specifies what router should be used to reach any addresses that aren't +specified elsewhere in our routing table. Now, when we try to connect +to say, 64.57.102.34, the information will be sent to 192.168.1.254 +which is responsible for delivering the data for us. Unfortunately, +we're still not quite through. We need some way of converting domain +names like slackware.com into IP addresses that the computer can use. +For that, we need to make use of a DNS server. +</p><p> +Fortunately, setting up your computer to use an external (or even an +internal) DNS server is very easy. You'll need to use your favorite +text editor and open the <code class="filename">/etc/resolv.conf</code> file. +Don't ask me what happened to the <span class="keycap"><strong>e</strong></span>. On my computer, +<code class="filename">resolv.conf</code> looks like this. +</p><pre class="screen"> +# /etc/resolv.conf +search lizella.net +nameserver 192.168.1.254 +</pre><p> +Most users won't need the "search" line. This is used to map hostnames +to domain names. Basically, if I attempt to connect to "barnowl", the +computer knows to look for "barnowl.lizella.net" thanks to this search +line. We're mainly interested in the "nameserver" line. This tells +Slackware what domain name servers (DNS) to connect to. Generally +speaking, these should always be specified by IP address. If you know +what DNS servers you should use, you can just add them one at a time to +individual nameserver lines. In fact, I don't know of any practical +limit to the number of nameservers that can be specified in +<code class="filename">resolv.conf</code>, so add as many as you like. Once this +is done, you should be able to communicate with other hosts via their +fully qualified domain name. +</p><p> +But Alan! That's a lot of hard work! I don't want to do this time and +again for dozens or even hundreds of machines. You're absolutely right, +and that's why smarter people than you and me created DHCP. DHCP +stands for Dynamic Host Control Protocol and is a method for +automatically configuring computers with unique IP addresses, netmasks, +gateways, and DNS servers. Most of the time, you'll want to use DHCP. +The majority of wireless routers, DSL or cable modems, even firewalls +all have DHCP servers to can make your life much easier. Slackware +includes two main tools for connecting to an exising DHCP server and +can even act as a DHCP server for other computers. For now though, +we're just going to look at DHCP clients. +</p><p> +First on our list is <span class="application">dhcpcd</span>(8), part of the +ISC DHCP utilities. Assuming your computer is physically connected to +your network, and that you have an operating DHCP server on that +network, you can configure your NIC in one shot. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>dhcpcd eth0</code></strong> +</pre><p> +If everything went according to plan, your NIC should be properly +configured, and you should be able to communicate with other computers +on your network, and with the Internet at large. If for some reason, +<span class="application">dhcpcd</span> fails, you may want to try +<span class="application">dhclient</span>(8). +<span class="application">dhclient</span> is an alternative to +<span class="application">dhcpcd</span> and works in basically the same way. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>dhclient eth0</code></strong> +Listening on LPF/eth0/00:1c:b3:ba:ad:4c +Sending on LPF/eth0/00:1c:b3:ba:ad:4c +Sending on Socket/fallback +DHCPREQUEST on eth0 to 255.255.255.255 port 67 +DHCPACK from 192.168.1.254 +bound to 192.168.1.198 -- renewal in 8547 seconds. +</pre><p> +So why does Slackware include two DHCP clients? Sometimes a particular +DHCP server may be broken and not respond well to either +<span class="application">dhcpcd</span> or +<span class="application">dhclient</span>. In those cases, you can fall back +to the other DHCP client in hopes of getting a valid response from the +server. Traditionally, Slackware uses +<span class="application">dhcpcd</span>, and this works in the vast majority +of cases, but it may become necessary at some point for you to use +<span class="application">dhclient</span> instead. Both are excellent DHCP +clients, so use whichever you prefer. +</p></div><div class="section" title="Automatic Configuration with rc.inet1.conf"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id319849"></a>Automatic Configuration with rc.inet1.conf</h2></div></div></div><p> +Manually configuring interfaces is an important skill to have, but it +can become tedious. No one wants to manually setup their Internet +connection every time the system boots. More importantly, you may not +always have physical access to the machine when it boots. Slackware +makes it easy to automatically configure ethernet (and wireless) cards +at system startup with <code class="filename">/etc/rc.d/rc.inet1.conf</code>. +For now, we're going to focus on traditional wired ethernet networking; +the next chapter will discuss various wireless options. +</p><p> +<code class="filename">rc.inet1.conf</code> is an incredibly powerful +configuration file, capable of configuring most of your network cards +automatically when Slackware is started. The file is filled with useful +comments, but there is also a man page that more thoroughly discusses +its use. To begin, we're going to look at some of the options used on +one of my personal machines. +</p><pre class="screen"> +# Config information for eth0: +IPADDR[0]="192.168.1.250" +NETMASK[0]="255.255.255.0" +USE_DHCP[0]="" +DHCP_HOSTNAME[0]="" +# Some lines ommitted. +GATEWAY="192.168.1.254" +</pre><p> +This represents most of the information necessary to configure a static +IP address on a single ethernet controller. +<span class="application">netconfig</span> will usually fill in these values +for a single ethernet device for you. If you have multiple network +cards in your machine and need all of them activated automatically at +boot time, then you'll need to edit or add additional entries into this +file in the same manner as above. First, let me go over some of the +basics. +</p><p> +As you may have already guessed, IPADDR[n] is the Internet Protocol +Address for the "n" network interface card. Typically, "n" corrosponds +to eth0, eth1, and so on, but this isn't always the case. You can +specify these values to pertain to a different network controller with +the INFAME[n] variable, but we will reserve that for the next chapter +on wireless networking, as it more commonly pertains to wireless +network controllers. Likewise, NETMASK[n] is the subnet mask to use +for the network controller. If these lines are left empty, then static +IP addresses will not be automatically assigned to this network +controller. The USE_DHCP[n] variable tells Slackware to (naturally) +use DHCP to configure the interface. DHCP_HOSTNAME[n] is rarely used, +but some DHCP servers may require it. In that case, it must be set to +a valid hostname. Finally, we come to the GATEWAY variable. It is +actually set lower in the file than it appears in my example, and it +controls the default gateway to use. You may be wondering why there is +no GATEWAY[n] variable. The answer to that lies in how Internet +Protocol works. I won't go into an indepth discussion on that subject, +but suffice it to say that there is only ever one default route that a +computer can use no matter how many interfaces are attached to it. +</p><p> +If you need to use static IP addressing, you will have to obtain a +unique static IP address and the subnet mask for the interface, as well +as the default gateway address, and enter those here. There is no place +to enter DNS information in <code class="filename">rc.inet1.conf</code>, so DNS +servers will have to be manually placed into +<code class="filename">resolv.conf</code> as we discussed above. Of course, if +you use <span class="application">netconfig</span>, this will be handled for +you by that program. Now let's take a look at another interface on my +computer. +</p><pre class="screen"> +# Config information for eth1: +IPADDR[1]="" +NETMASK[1]="" +USE_DHCP[1]="yes" +DHCP_HOSTNAME[1]="" +</pre><p> +Here I am telling Slackware to configure eth1 using DHCP. I do not need +to set the IPADDR[1] or NETMASK[1] variables when using DHCP (in fact, +if they are set, they will be ignored). Slackware will happily contact +a DHCP server as soon as the machine begins to boot. +</p></div></div><div class="chapter" title="Chapter 14. Wireless Networking"><div class="titlepage"><div><div><h2 class="title"><a name="id329344"></a>Chapter 14. Wireless Networking</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id326142"><span class="application">iwconfig</span></a></span></dt><dt><span class="section"><a href="#id359178">Wired Equivilant Protection (or Lack Thereof)</a></span></dt><dt><span class="section"><a href="#id334833">WPA</a></span></dt><dt><span class="section"><a href="#id334290">rc.inet1.conf revisited</a></span></dt></dl></div><div class="section" title="iwconfig"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id326142"></a><span class="application">iwconfig</span></h2></div></div></div><p> +Wireless networking is somewhat more complicated than traditional wired +networking, and requires additional tools for setup. Slackware includes +a diverse collection of wireless networking tools to allow you to +configure your wireless network interface card (WNIC) at the most basic +level. We won't cover everything here, but should give you a solid +foundation to get up and running quickly. The first tool we are going +to look at is <span class="application">iwconfig</span>(8). When run without +any argument, <span class="application">iwconfig</span> displays the current +wireless information on any and all NICs on your computer. +</p><pre class="screen"><code class="prompt">darkstar:~# </code><strong class="userinput"><code>iwconfig</code></strong> +lo no wireless extensions. + +eth0 no wireless extensions. + +wmaster0 no wireless extensions. + +wlan0 IEEE 802.11abgn ESSID:"nest" + Mode:Managed Frequency:2.432 GHz Access Point: +00:13:10:EA:4E:BD + Bit Rate=54 Mb/s Tx-Power=17 dBm + Retry min limit:7 RTS thr:off Fragment thr=2352 B + Encryption key:off + Power Management:off + Link Quality=100/100 Signal level:-42 dBm + Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 + Tx excessive retries:0 Invalid misc:0 Missed beacon:0 + +tun0 no wireless extensions. +</pre><p> +Unlike wired networks, wireless networks are "fuzzy". Their borders are +hard to define, and multiple networks may overlap one another. In order +to avoid confusion, each wireless network has (hopefully) unique +identifiers. The two most basic identifiers are the Extended Service +Set Identifier (ESSID) and the channel or frequency for radio +transmission. The ESSID is simply a name that identifies the wireless +network in question; you may have heard it referred to as the network +name or something similar. Typical wireless networks operate on 11 +different frequencies. In order to connect to even the most basic +wireless network, you will have to setup these two pieces of +information, and possibly others, before setting up things like the +WNIC's IP address. +</p></div><div class="section" title="Wired Equivilant Protection (or Lack Thereof)"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id359178"></a>Wired Equivilant Protection (or Lack Thereof)</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="WPA"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id334833"></a>WPA</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="rc.inet1.conf revisited"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id334290"></a>rc.inet1.conf revisited</h2></div></div></div></div></div><div class="chapter" title="Chapter 15. Basic Networking Commands"><div class="titlepage"><div><div><h2 class="title"><a name="id284408"></a>Chapter 15. Basic Networking Commands</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id348624">Network Diagnostic Tools</a></span></dt><dt><span class="section"><a href="#id333340">Web Browsers</a></span></dt><dt><span class="section"><a href="#id351638">FTP Clients</a></span></dt><dt><span class="section"><a href="#id317884">NNTP Clients</a></span></dt><dt><span class="section"><a href="#id341101">Remote Access</a></span></dt></dl></div><div class="section" title="Network Diagnostic Tools"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id348624"></a>Network Diagnostic Tools</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Web Browsers"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id333340"></a>Web Browsers</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="FTP Clients"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id351638"></a>FTP Clients</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="NNTP Clients"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id317884"></a>NNTP Clients</h2></div></div></div></div><div class="section" title="Remote Access"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id341101"></a>Remote Access</h2></div></div></div></div></div><div class="chapter" title="Chapter 16. Package Management"><div class="titlepage"><div><div><h2 class="title"><a name="id320396"></a>Chapter 16. Package Management</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id358328"><span class="application">pkgtool</span></a></span></dt><dt><span class="section"><a href="#id352958">Installing, Removing, and Upgrading Packages</a></span></dt><dt><span class="section"><a href="#id341343"><span class="application">pkgtool</span></a></span></dt></dl></div><div class="section" title="pkgtool"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id358328"></a><span class="application">pkgtool</span></h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Installing, Removing, and Upgrading Packages"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id352958"></a>Installing, Removing, and Upgrading Packages</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="pkgtool"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id341343"></a><span class="application">pkgtool</span></h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div></div><div class="chapter" title="Chapter 17. Keeping Track of Updates"><div class="titlepage"><div><div><h2 class="title"><a name="id292742"></a>Chapter 17. Keeping Track of Updates</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id314047">The -stable Branch</a></span></dt><dt><span class="section"><a href="#id324804">Upgrading Slackware Versions</a></span></dt></dl></div><div class="section" title="The -stable Branch"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id314047"></a>The -stable Branch</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Upgrading Slackware Versions"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id324804"></a>Upgrading Slackware Versions</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div></div><div class="chapter" title="Chapter 18. The Linux Kernel"><div class="titlepage"><div><div><h2 class="title"><a name="id328461"></a>Chapter 18. The Linux Kernel</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id322300">What Does the Kernel Do?</a></span></dt><dt><span class="section"><a href="#id325022">Working with Modules</a></span></dt><dt><span class="section"><a href="#id353213">Compiling A Kernel and Why to do So</a></span></dt></dl></div><div class="section" title="What Does the Kernel Do?"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id322300"></a>What Does the Kernel Do?</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Working with Modules"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id325022"></a>Working with Modules</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div><div class="section" title="Compiling A Kernel and Why to do So"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id353213"></a>Compiling A Kernel and Why to do So</h2></div></div></div><p> +Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do +eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad +minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip +ex ea commodo consequat. Duis aute irure dolor in reprehenderit in +voluptate velit esse cillum dolore eu fugiat nulla pariatur. +</p></div></div></div></body></html> |