linuxcommand-announce

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] The Linux Command Line - Second Draf...

[William S. <bs...@pa...>]

Hi Everyone,

I just posted the second draft of my book. This incorporates items from
my "to do" list. It does not yet include any changes from the review
team. Reviewers may switch to this version if they wish (just indicate
that you are reviewing version 09.08 of the book) but may also continue
with the first draft. The changes in this version are not extensive but
it should read a little better. A few new items were added, and the
table of contents now provides links to the individual chapters making
navigation somewhat easier. Enjoy!

The new PDF is named TLCL-09.08.pdf and is available here.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
8/14/2009 09:34:00 AM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] I'm Looking For Reviewers

[William S. <bs...@pa...>]

Sorry about my long absence, but as you will see, I have an excuse:

Hello All,

I have just finished the first draft of a book I'm writing titled, "The
Linux Command Line" to be released under a Creative Commons license.
With the initial writing completed, it's time for some editing and
review. That means I'm looking for folks willing to perform some
reviewing. In particular, I need technical reviewers who can gently
point out my technical and historical errors, and I need less
experienced users who can find areas where my explanations are unclear.
Don't worry about grammar and spelling and such, I have a "real" editor
for that. At this stage I need gurus and sample users to test this
thing.

The book is fairly long (about 475 pages) so a good review will take
some time and effort on the part of any volunteers. If you make a
serious contribution, I will add your name to the list of contributors
in the "Acknowledgments" section of the first chapter. Don't laugh,
that's all I got for doing a technical review on O'Reilly's "Bash
Cookbook."

Unlike Bash Cookbook however, my book will be freely distributable in
PDF format but I am reserving the right to sell printed versions.

Please feel free to take a look at the draft. It can be downloaded from
my Sourceforge site at:

http://downloads.sourceforge.net/sourceforge/linuxcommand/TLCL-09.07.pdf?use_mirror=master

If you decide that you'd like to help out with the review, let me know
and I will provide further details.

Many thanks!

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
7/22/2009 06:41:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] "We Are Linux" Video Finalists

[William S. <bs...@pa...>]

The Linux Foundation has announced the finalists in there "We Are
Linux" competition. While I consider all the entries rather weak, my
favorite is this one:








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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
4/09/2009 05:40:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

Today, we will finish up with printing by taking a look at the command
line tools provided by CUPS.

CUPS supports two different families of printer tools. The first,
Berkley or LPD comes from the Berkley Software Distribution (BSD)
version of Unix and the second is SysV from the System V version of
Unix. Both families include comparable functionality, so choosing one
over the other is really a matter of personal taste.

Setting A Default Printer
A printer can be set as the default printer for the system. This will
make using the command line print tools easier. To do this we can
either use the web-based interface to CUPS at http://localhost:631 or
we can use the following command:

lpadmin -d printer_name

where printer_name is the name of a print queue we defined in Part 6 of
the series.

Sending A Job To The Printer (Berkley-Style)
The lpr program is used to send a job to the printer. It can accept
standard input or file name arguments. One of the neat things about
CUPS is that it can accept many kinds of data formats and can (within
reason) figure out how to print them. Typical formats include
PostScript, PDF, text, and images such as JPEG.

Here we will print a directory listing in three column format to the
default printer:

ls /usr/bin | pr -3 | lpr

To use a different printer, append -P printer_name to the lpr command.
To see a list of available printers:

lpstat -a

Sending A Job To The Printer (SysV-Style)
The SysV print system uses the lp command to send jobs to the printer.
It can be used just as lpr in our earlier example:

ls /usr/bin | pr -3 | lp

however, lp has a different set of options. For example to specify a
printer, the -d (for destination) option is used. lp also supports many
options for page formatting and printer control not found with the lpr
command.

Examining Print Job Status
While a print job is being printed, you may monitor its progress with
the lpq command. This will display a list of all the jobs queued for
printing. Each print job is assigned a job number that can be used with
to control the job.

Terminating Print Jobs
Either the lprm (Berkley) or cancel (SysV) commands can be used to
remove a job from a printer queue. While the two commands have
different option sets, either command followed by a print job number
will terminate the specified job.

Getting Help
The following man pages cover the CUPS printing commands

lp lpr lpq lprm lpstat lpoptions lpadmin cancel lpmove

In addition, CUPS provides excellent documentation of the printing
system commands in the help section of the online interface to the CUPS
server at:

http://localhost:631/help

Select the "Getting Started" link and the "Command Line Printing And
Options" topic.

A Follow Up On Part 4
Midnight Commander allows direct access to its file viewer and built in
text editor. The mcview command can be used to view files and the
mcedit command can be used to invoke the editor.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
4/09/2009 04:32:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] LinuxCommand.org (And Others) Under ...

[William S. <bs...@pa...>]

Since Thursday my domain registrar, register.com, has been under heavy
distributed denial of service (DDoS) attack. This has, at times, made
all or part of LinuxCommand.org unavailable. Here is the latest news:

Dear William,

Earlier today we communicated to you we were experiencing intermittent
service disruptions as a result of a distributed denial of service
(DDoS) attack – an intentionally malicious flooding of our systems
from various points across the internet.

We want to update you on where things stand.

Services have been restored for most of our customers including hosting
and email. However for some of our customers, services are not fully
restored. We know this is unacceptable.

We are using all available means to restore services to every one of
our customers and halt this criminal attack on our business and our
customers’ business. We are working round the clock to make that happen.

We are committed to updating you in as timely manner as possible,
please check your inbox or our website for additional updates.


Thank you for your patience.



Larry Kutscher
Chief Executive Officer
Register.com



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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
4/04/2009 07:40:00 AM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Another NYT Story On Netbooks

[William S. <bs...@pa...>]

Light and Cheap, Netbooks Are Poised to Reshape PC Industry

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
4/03/2009 06:10:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Tip: Redirecting Multiple Command Ou...

[William S. <bs...@pa...>]

Let's imagine a simple script:

#!/bin/bash

echo 1
echo 2
echo 3

Simple enough. It produces three lines of output:

1
2
3

Now let's say we wanted to redirect the output of the commands to a
file named foo.txt $F

Again, pretty straightforward, but what if we wanted to pipe the output
of all three echo commands into less? We would soon discover that this
won't work:


#!/bin/bash

F=foo.txt

echo 1 | less
echo 2 | less
echo 3 | less

This causes less to be executed three times. Not what we want. We want
a single instance of less to input the results of all three echo
commands. There are four approaches to this:

Make A Separate Script
script1:


#!/bin/bash

echo 1
echo 2
echo 3

script2:


#!/bin/bash

script1 | less

By running script2, script1 is also executed and its output is piped
into less. This works but it's a little clumsy.

Write A Shell Function
We could take the basic idea of the separate script and incorporate it
into a single script by making script1 into a shell function:


#!/bin/bash

# shell function
run_echoes () {
echo 1
echo 2
echo 3
}

# call shell function and redirect
run_echoes | less

This works too, but it's not the simplest way to do it.

Make A List
We could construct a compound command using {} characters to enclose a
list of commands:


#!/bin/bash

{ echo 1; echo 2; echo 3; } | less

The {} characters allow us to group the three commands into a single
output stream. Note that the spaces between the {} and the commands, as
well as the trailing semicolon after the third echo, are required.

Launch A Subshell foo.txt &

This doesn't make much sense for our echo commands (they execute too
quickly to bother with), but if we have commands that take a long time
to run, this technique can come in handy.

Enjoy!

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
4/03/2009 03:02:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

In this installment, we will tackle printing. If you recall from the
second installment when we installed Debian on the system, we selected
the "print server" group of packages to included with our installation.
This installed CUPS (Common Unix Printing System) and related programs.
This set of packages allows the system to print local print jobs and
(if configured to do so) act as a print server to other systems on the
local network.Installing cups-pdfOne of the cool things we can do is
install the cups-pdf package which supports a virtual printer that
creates PDF files in lieu of actual printed output. After installation,
we will take advantage of the package to demonstrate how to configure
CUPS. Using apt-get we can install the package this way:sudo apt-get
install cups-pdfConfiguring CUPSCUPS, by default, makes available a
web-based configuration system. To access it, we will use w3m:w3m
http://localhost:631which will open the web page on the local network
interface using port 631. After the page opens, we will get a screen
like this:With this interface, you can configure:
- Local USB, parallel port and virtual printers.
- Remote IPP (Internet Printing Protocol) printers. Cups will find them
automatically if your network allows it.
- Remote SMB (Windows shared) printers. To add the PDF virtual printer,
follow this procedure. Note that at some point you may be prompted to
enter a user name and password for CUPS. Regular users are not allowed
to make system-wide changes to the printing system. When prompted enter
the user name "root" and the root password to continue.
- Using the tab key, move the cursor to the link labeled "Add Printer"
and press enter.
- We will see a new page with some input fields. They are delimited
with square bracket characters ([]). To enter data into the fields,
move the cursor to the field and press enter. A text prompt will appear
at the bottom of the screen.
- In the first field, "Name:" we will enter the name of the printer to
be added. This name is like a file name and should be one word with no
spaces. We will call our new printer, PDF. Type the letters PDF at the
text prompt and press enter.
- Press the tab key to move to the next field, "Location:" and
enter "localhost" using the text prompt.
- Press the tab key to move to the next field, "Description:" and
enter "CUPS-PDF Virtual Printer."
- Press the tab key to move to the link labeled "Continue" and press
enter. After a few seconds, we will see a new screen with a pull-down
box of printer devices. Using the tab key move the cursor to the field
labeled "Device:" and press enter. The contents of the list will appear.
- Using the arrow keys, select the entry "CUPS-PDF (Virtual PDF
Printer)" and press enter.
- Press the tab key to move to the "Continue" link. Press enter.
- After a few seconds, a new screen will appear, again with a pull-down
box. This box is for selecting drivers. The CUPS-PDF driver does not
really need this, so open the box labeled "Make:" and select "Generic"
and press enter.
- Move to the "Contiune" link and press enter.
- The next screen will appear and we can skip over the fields (they
should already be correct.) Move the cursor to the link labeled "Add
Printer" and press enter.
- You will briefly see a screen announcing that the printer has been
successfully added. It will be followed by a page of printer options.
If you need to change any, such as default paper size, do so now. When
done, move to the link labeled "Set Printer Options" and press enter.
- The final screen contains a summary of the printer setup and contains
a list of links for controlling the printer including printing a test
page.At this point we are done. You may move to the "Home" link at the
top of the page to repeat the process to add more printers.That's all
for this installment. Next time we will look at some printer commands
that we can use with our new printing capability.

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/27/2009 04:47:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] A Very Funny Linux Video

[William S. <bs...@pa...>]

At the risk of being offensive, this is a very funny video.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/23/2009 07:50:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

In today's episode, we'll look at sudo and some text editing stuff. So
fire up your text boxes and let's get going!sudoIf you're an Ubuntu
user, you probably already know a little about sudo. It's the command
you use to get temporary administrative privileges for doing such
things as editing configuration files and installing software. sudo
allows users to enter their own password instead of the root password
to perform privileged tasks. Further, sudo can be configured to allow
specific users specific privileges. For example, a user can be allowed
to only execute a specific command as the superuser.sudo is invoked
this way:sudo commandwhere command is the command to be executed with
escalated privileges.One of the inconveniences on our all-text system
is that we must either login as root or use the su command to shut the
system down, since only the superuser is allowed to shutdown the
system. A sensible precaution considering that Linux systems are
designed to support multiple users at the same time.To fix this
problem, we'll install sudo on our system. We can do this with either
aptitude or apt-get. As root, enter the following command:apt-get
install sudoand the sudo package will be installed.sudo is controlled
by a configuration file named /etc/sudoers. The sudoers file is a
little unique in that it wants to be edited only with the visudo
program. You can actually edit it with any text editor, but the visudo
program checks the syntax of the file to help prevent errors. This is
important for any file with the security implications of sudoers.To
edit the file, we simply (as root again) enter the command:visudoand
the following screen will appear:Despite the name, the visudo program
uses the nano text editor and not vi. This makes it much easier for new
users. Our change to the sudoers file is very simple. Add this line in
the section labled "User privilege specification" and then save the
file and exit the editor by first typing ctrl-o and then ctrl-x.:me
ALL=(ALL) ALLSubstitute your user name for the name "me" and this
configuration will allow you to execute any command with root
privileges by entering your own password.To allow a user of the system
to only run the poweroff command (performs the same as shutdown but
does not require the time to be specified), we could add this line to
the file:username ALL=(ALL) /sbin/poweroffwhere username is the name of
the user.nanoAs we have seen, our Debian system has the nano text
editor installed by default. nano is a clone of an earlier editor named
pico that is included with the pine email program. pine has some
license issues that prevents it from being included with some Linux
distributions so a replacement version of its editor was developed.To
use nano, type the following:nano textfilewhere textfile is the name of
a file to edit.As text-based editors go, it's pretty easy to use. It
provides a small list of commands at the bottom of the screen. Pressing
the ctrl-g key brings up the help screen which displays all of its
commands. nano does support the mouse. See the nano man page for
details.nano uses a global configuration file named /etc/nanorc and, if
available, a local configuration file named ~/.nanorc. To make an
initial copy of the local configuration file, copy the global file to
your home directory:me@linuxbox:~$ cp /etc/nanorc ~/.nanorcOne useful
change we can make to the configuration file is the activation of
syntax highlighting. This can be done by removing comments from several
lines at the end of the file. The last section of the configuration
file, the "Color setup" section, has a number of "include" statements
which load syntax definitions. To enable syntax highlighting support,
remove the comment symbol from the beginning of the line. Change lines
like this:## Bourne shell
scripts#include "/usr/share/nano/sh.nanorc"to:## Bourne shell
scriptsinclude "/usr/share/nano/sh.nanorc"for as many languages as you
wish to support.Syntax highlighting is automatically activated based on
the file name extension of the file being edited. For example, if we
edit a file named foo.html and the HTML syntax definition has been
included in the .nanorc file, the foo.html file will be displayed with
syntax highlighting when loaded. The colors can be toggled on and off
by pressing alt-y. This presents a problem for shell scripts, however
as most do not have a file extension in their name. This can be solved
in one of two ways. First, add the extension ".sh" to the file name, or
second, invoke nano with the -Y sh option, which forces the selection
of the sh highlighting. It might be a good idea to add an alias such
as:alias nano-sh='nano -Y sh'to your .bashrc file to make this more
convenient.vimReal Linux users, of course, don't use nano. They use
vim, the enhanced replacement for the traditional Unix editor, vi. The
version of vim installed by default on our system is called vim-tiny, a
subset of the full package. I recommend installing the full vim
package. This can be done with apt-get like so:apt-get install vimI'm
not going to cover vim in this posting as it would take too much space
(it consumed a rather chapter in my upcoming book) but there is a
pretty good on-line book (in PDF format) that describes it in detail.
See The Vim Book. Seriously, to be a real Linux person you should take
the time to learn it. I know its not easy, but you'll really enjoy
lording it over the other Linux newbies once you do.Well, that's all
for this time. See you again soon!

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/21/2009 07:24:00 AM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

In this installment, we will explore web browsing and install a couple
of packages to help with file management.A Text Web Browser?Yes, there
are such things. In fact there are several available for Linux. Our
Debian workstation has one installed by default. Called w3m, it is a
full featured browser that operates in text mode. So what can you do
with it? Well, we won't be watching YouTube with it, that's for sure,
but many well written web sites (especially those designed to follow
acceptable standards of accessibility) will render just fine. We can
try it out:me@linuxbox:~$ w3m linuxcommand.organd after a few seconds
we will see this:The arrow keys will navigate, and the tab key will
advance from link to link. Shift-h will bring up the help screens and
shift-b will perform a "back" function (this will get you out of help
too). Press the q key to quit w3m. The program can do tabbed browsing,
render tables and has a number of command line tricks. This blog
renders fine too, so you can now follow along directly on our all-text
system.Unfortunately, there is a bug that prevents w3m from using the
mouse on the console to help with navigation. Fortunately, there are
other browsers that you can install. See the link at the end of this
article.Automatically Mounting USB DevicesIf we insert a USB flash
drive into our system, we will see a kernel message appear on the
screen. This is because the kernel sends its messages to the console in
the hopes that an ever-vigilant operator (that's you) is paying
attention. However this message means very little as it only announces
the fact that the kernel has detected a device attached to the USP
port. It does not mean that the system has done anything useful, like
mounting the device. We could manually mount the device, that that is a
nuisance.To solve this problem we will install a package called
usbmount that can automatically mount USB devices. We can do this using
aptitude. Just search for the "usbmount" package and install it. We
described the process in installment 3.After the package is installed,
we must modify its configuration file to allow support for VFAT file
systems, the type most often used on USB drives. As a precaution,
usbmount does not enable VFAT since the kernel does not fully support
the "sync" mount option on VFAT file systems. Normally, usbmount allows
USB devices to removed without unmounting. It does this by keeping file
systems "synchronized," that is, it immediately writes changes to the
device versus waiting to consolidate multiple write for improved
performance. With VFAT enabled, the user must issue a sync command
before removing a USB VFAT device.After the package is installed, we
need to (as root) edit the /etc/usbmount/usbmount.conf file and change
the following two lines:FILESYSTEMS="ext2 ext3"to:FILESYSTEMS="ext2
ext3
vfat"and:FS_MOUNTOPTIONS=""to:FS_MOUNTOPTIONS="-fstype=vfat,gid=floppy,dmask=0007,fmask=0117"After
the configuration file is modified, usbmount will automatically mount
VFAT devices. You will find the mount point in the /media directory.
When a flash drive is inserted we can verify the mount using
df:me@linuxbox:~$ dfFilesystem 1K-blocks Used Available Use% Mounted
on/dev/hda1 18856292 980140 16918280 6% /tmpfs 160096 0 160096
0% /lib/init/rwudev 10240 88 10152 1% /devtmpfs 160096 0 160096
0% /dev/shm/dev/sda1 15560 5944 9616 39% /media/usb0and we see that the
drive has been mounted on /media/usb0. Just remember to use the sync
command before removing the device, or really bad things may happen to
the drive:me@linuxbox:~$ syncMidnight CommanderThe last package we will
install in this episode is Midnight Commander, a text based file
manager. Using aptitude, install the mc package and the following
additional packages that are recommended: arj, bzip2, odt2txt, unzip,
and zip. If you prefer, you can use apt-get to install the packages as
the mc package is a little hard to find using aptitude:linuxbox:~#
apt-get install mc arj bzip2 odt2txt unzip zipAfter mc is installed we
can fire it up:me@linuxbox:~$ mcand the following screen will
appear:The numbered blocks along the bottom of the screen correspond to
the function keys, F1-F10 and permit access to many of the programs
functions and it has a lot of them! Unlike w3m, the mouse is well
supported by mc.That's all for this installment. While you're waiting
for Part 5, study Midnight Commander. It has a help function and a man
page. That should keep you busy for a while! Also, if you are
interested in other text-based web browsers, check out the Text Mode
Browser Roundup from Linux Journal.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/11/2009 05:37:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Dvorak Likes Linux

[William S. <bs...@pa...>]

I never thought that I would live long enough to see it, but John C.
Dvorak, professional curmudgeon likes Ubuntu!

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/09/2009 07:05:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Interview With Steve Bourne, Creator...

[William S. <bs...@pa...>]

Computerworld has a very interesting interview with Steve Bourne, the
author of sh (the ancestor of bash) where he talks about the history of
the Unix shell. A good read for you Unix history buffs out there.

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/05/2009 01:47:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

In this installment we'll learn how to navigate the text environment
and install our first packages.If you have gotten through parts 1 and 2
of our series, you now have a sparkling new Linux system that displays
-- a prompt! But if you think it only displays one prompt, you'd be
wrong, as we shall soon see.Let's fire up our system and log in again
as the root user.One of the commands I often use is locate, which
rapidly searches a small database of files installed on the system.
locate is installed on our system but when we try to use it we get the
following message:linuxbox:~# locate foolocate: can not open
`/var/lib/mlocate/mlocate.db': No such file or directoryThis message
appears when you try to use the locate command before the database is
created. Normally the database is rebuilt each night by a cron job, but
unless you let the machine run overnight, the database will never get
built. We'll fix this problem in a little bit, but to solve the problem
in the meantime, we'll run the database update program
manually:linuxbox:~# updatedbAfter it completes, locate should start to
work. If you are unfamiliar with this wonderful utility, now is a good
time to look at its man page.If we enter the command:linuxbox:~# locate
fooWe will get back a long list of filenames containing the
string "foo." Go ahead and do this. Notice how the list scrolls off the
top of the screen. Next, type shift-PageUp and notice how we are able
to scroll up the list. Shift-PageDown scrolls downward.The terminal
screen is only 80 characters wide but sometimes a command will output
lines wider than 80 characters. This will usually cause the text to
wrap but in some rare instances it will actually go off the edge of the
screen. In these cases, you can scroll the screen sideways by using the
shift-right arrow and shift-left arrow.To see the next keyboard trick,
type Alt-F2 and you will see a new login prompt. Actually you are
seeing another virtual terminal you can log into. Go ahead and log in
using your ordinary user name and password. Now try the who
command:me@linuxbox ~$ whoroot tty1 2009-03-04 13:49me tty2 2009-03-04
14:28As we can see, we have two users logged in. Type Alt-F3 and we'll
see another virtual terminal. In fact, on our system, Alt-F1 through F6
provide separate terminals we can use. You can use Alt-right and left
arrows to rapidly cycle through them.Wouldn't It Be Great If The Mouse
Worked?Let's go back to the first terminal session where root is logged
in by typing Alt-F1. Then start up the aptitude program:linuxbox:~#
aptitudeaptitude is a fancy character based way to install packages on
Debian and other Debian-based distributions. It has many features and
is a handy way to manage packages on our system. The apt-get program is
also available. aptitude features a multi-pane screen:It took me a few
minutes to figure out the user interface, but after installing a few
packages with it, I figured it out. We're going to use aptitude to
install a couple of packages. We'll use its search feature to help us
out. Type / and a search prompt should appear. Enter "anacron" and it
should find the package in its database.You can use the tab key to
toggle between the two display panes. With the package name
highlighted, press the + key to mark the package for installation.
Next, let's do another search, this time for "gpm". If it does not find
it the first time, type "n" to search for the next occurrence. Repeat
until it finds a package named simply gpm. This use of / (search) and n
(next) is the same as the less program. Again, type + to mark the
package for installation.With our two packages selected, it's time to
install them. We do this by typing "g" (for "go".) aptitude will
display a summary of the actions it is about to take and by
pressing "g" a second time, the installation will commence. When
installing gpm for the first you will see an error message about being
unable to shut down the daemon. This may be safely ignored.When the
aptitude screen returns, type "q" to quit.We have now installed
anacron, which will make sure that periodic tasks (like running
updatedb) take place even if the machine is not run continuously. We
also installed gpm which should make the mouse work. Some of the
programs that we will install in upcoming installments can use a mouse,
but its most useful feature is that we can now use the mouse to copy
and paste text, just like we can on the X display. The only difference
is that the right button is used to paste rather than the middle
button.You can terminate your extra terminal sessions by typing "exit"
and root can shut down the machine by:linuxbox:~# shutdown -h nowThat's
all for today. See you again soon!

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/04/2009 01:23:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Linuxcommand.org Terminal Screenshot...

[William S. <bs...@pa...>]

I recently received this email from inquisitive reader Dermot:HiI was
going through your website http://linuxcommand.org tonight and find it
really easy to follow how the commands and descriptions are laid out. I
have a question about the screenshots you use.The terminal screenshots
have a black background, with "[me@llinuxbox me}$" in green and the
commands to be run in white. How did you get this colour scheme? Ive
been asking on Ubuntuforums and other forums, as it would really make
the lines on which you enter commands stand out against the output
results of those commands.Please get back to me if you get a
chance.ThanksDermotIrelandThanks Dermot for taking the time to write.
The "screen shots" you refer to aren't actually screen shots at all.
They're implemented in hand-coded HTML and CSS, but you can create the
same effect on your own system. Here's how:The contents of your prompt
are defined in an shell variable called PS1. You can examine its
contents like this:me@linuxbox ~$ echo
$PS1${debian_chroot:+($debian_chroot)}\u@\h:\w\$This example is from an
Ubuntu system. Other distributions will be different. Current Profile
dialog in gnome-terminal to set the color scheme to "White on
black":Next, you need to add some ANSI color codes to the prompt string
contained in PS1. To change the prompt to green and then back to its
original colors (so that subsequent text will remain white), you need
to change the prompt string to
this:\033[0;32m${debian_chroot:+($debian_chroot)}\u@\h:\w\$\[\033[0m\]You
can test your prompt by setting the PS1 variable this way:me@linuxbox
~$
PS1="\033[0;32m${debian_chroot:+($debian_chroot)}\u@\h:\w\$\[\033[0m\] "After
you are satisfied with the new prompt design, you can make it permanent
by adding these two lines to your .bashrc
file:PS1="\033[0;32m${debian_chroot:+($debian_chroot)}\u@\h:\w\$\[\033[0m\] "export
PS1Hope this helps!You can read more about configuring the prompt at
the Linux Documentation Project. They have an excellent HOWTO document
entitled:The Bash-Prompt HOWTO

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
3/02/2009 07:04:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

In this episode, we will choose the Linux distribution and perform the
installation.Choosing A DistributionAfter some consideration, I
selected Debian 5.0 for our workstation project for three reasons:
- Debian is fairly simple on a conceptional level. Good,
straightforward design with good documentation. It's also capable of
being installed on very small machines. Its minimum memory requirement
is only 44 MB.
- Its package repository is huge. With over 22,000 packages, we are
likely to find a good selection of text based applications for our
project.
- It just came out and I wanted to play with it ;-)Creating
Installation MediaWith that decision out of the way, we next decide on
the installation media. I chose the "netinst" (also called the "minimal
CD") option. This is a downloadable CD image that contains a minimal
base system. Additional packages are installed from the Internet. The
install image is 150 MB, much smaller than the full install CDs. To use
this option you must have a working network connection. If you need
other installation options, take a look at the Debian Installation
Guide for guidance.You can download the installation image from
here.The last step is creating the installation CD. I will assume that
your present system, Linux or otherwise is capable of that and that you
know how to do it.InstallationWith our machine ready, it's time to boot
up with our install CD. After the CD boots you will receive an
attractive Debian splash screen listing various install options. For
our purposes, select "Install", not "Graphical Install".The installer
is pretty easy to use and in most cases the default selections are
fine. The arrow keys move from selection to selection as do the
tab/shift-tab keys. The space bar is used to toggle the contents of
check boxes.
- When the prompt appears for disk partitioning, select "Guided - Use
entire disk" and "All files in one partition".
- At the "Set up users and passwords" screen, you will be prompted to
set the password for the root account. If you have been using Ubuntu up
to this point, I have to explain that Debian, like most Linux
distributions has a discreet root account rather than using sudo for
everything as Ubuntu does. Much of the early work we will perform on
the system will require root access. Choose a root password that is
both strong, and one that you can easily remember.
- Next, you will be prompted to create your personal account. In
keeping with LinuxCommand tradition, I named my machine "Linuxbox" and
created a user account named "me". You, of course, can use any name you
like.
- At the "Select and install software" screen you will be presented
with a group of check boxes for different sets of packages to install.
Using the space bar, select the "Print server" group and unselect
the "Desktop environment" group.
- If you have installed the system using the entire disk as suggested
above, answer "yes" to the prompt on the "Install the GRUB boot loader
on the hard disk" screen to install GRUB in the disk's master boot
record (MBR).The install should complete and prompt you to remove the
install CD. Next, the machine will reboot and we should see the fruits
of our labors.A lot of boot messages should scroll by after the reboot
and you will see at the very bottom a login prompt like this:Debian
GNU/Linux 5.0 linuxbox tty1linuxbox login:Enter the name root and then
the root password and we will see a prompt like this:linuxbox: ~#Enter
the command shutdown -h now and the machine will shutdown.We're done
for today.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/27/2009 05:32:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/27/2009 05:30:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Project: Building An All-Text Linux ...

[William S. <bs...@pa...>]

When I see an old PC in the trash, I have a strong urge to rescue and
adopt it like a stray puppy. My wife, of course, has very effective
ways of constraining my behavior in this regard, so I don't have nearly
as many computers as I want. I hate seeing computers go to waste. I
figure if the processor and the power supply are still working, the
computer should be doing something. So what if it can't run the latest
version of Windows? It can still run Linux!Over the next few weeks, I
will show you how to take an old, slow computer and make it into a
text-only Linux workstation with surprising capabilities, including
document production, email, instant messaging, audio playback, USENET
news, calendaring, and, yes, even web browsing.Why would anyone want to
build a text-only workstation? I don't know. Because we can! And
besides, it's a great way to learn a bunch of command line stuff and
that's why you're here, right?So if you want to play along, find
yourself a computer with a least the following:
- Pentium processor or above
- 64 MB or more of RAM
- 2 GB or larger hard disk
- PS/2 or USB mouse
- A PCI Network card (no ISA or wireless please)We're going to format
over the existing software so don't use a valuable machine for this
project. Many machines from the Windows 98 era should be good
candidates. I will be using an HP Pavilion (circa 1996) with a 600 MHz
Celeron, 320 MB of RAM and a 20 GB disk.Good luck and I will see you
again soon!

--
Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/25/2009 05:11:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Bash 4.0 Released Today

[William S. <bs...@pa...>]

Version 4.0 of everyone's favorite shell program was released today. I
imagine this will be showing up in new Linux distributions soon. A copy
of the release announcement is here.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/23/2009 03:38:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] The Unix (Linux) Frame Of Mind

[William S. <bs...@pa...>]

If you are migrating from Windows to Linux, one of the barriers you
will encounter (besides the myriad superficial differences in the user
interface) is the whole "culture thing."Using a Unix-like operating
system involves more than learning where the buttons are located on the
desktop. It requires a different way of thinking about your computer.
On top of that, Linux requires that you learn about your relationship
with the Free and open source software communities. That will be the
subject, no doubt, of many future postings, but for now we'll talk
about the Unix frame of mind.To understand Unix, you have to understand
its historical context. Unix certainly has its faults, but if you
understand its history, you can see that many of its "features" are due
to the state of computing during its formative years. But it's also
important to realize that just because something is old does not mean
that it is necessarily bad. Take for instance, the command line
interface. If you listen to pundits and the PC magazine writers, you
would think that the command line is the equivalent of waterboarding to
the modern computer user. I liken use of a graphical user interface to
watching television and the command line to reading a book. They are
very different, but both are valid (and valuable) if used in the proper
way.So what is "the Unix frame of mind?" It is based on some the
following principles:The computer is multi-user. Unix was designed
for "big" computers. Big, expensive computers that supported many users
at the same time. This has a number of implications. For one, it meant
a different security model. On a multi-user computer, it is essential
that one user cannot trash another user, or the entire system. It also
implies that communities can form among the computer's users. If you
have Fedora or any of the other Red Hat family of Linux distributions,
you may have noticed that it runs sendmail by default. This is part of
the Unix tradition. Users on a system send email to each other. The
first form of instant messaging was the write command which sent a text
message to another user's terminal session.Automate everything. Back in
the 1960's IBM used a marketing slogan, "Machines should work. People
should think." Yet today, we have millions of office workers sitting in
front of PCs pumping their mice all day. Why? It's because the computer
is not doing the work. The human is. The Unix way is to instruct the
computer how to do the work and then forget about it. Back in the 1990s
I marveled at the cron daemon. It could perform tasks on a scheduled
basis. I remember leaving my PC on all night and letting it do the work
I needed and having a summary of the results each morning. It did the
work so I didn't have to.Everyone programs. The computer is a tool, or
rather, it is a huge collection of tools that can be arranged to
perform work. To do this, you must program. You have to break your
tasks into simple steps and arrange the tools to perform them. Unix
actually makes this fairly simple. You can create pipelines of commands
or write shell scripts. Have you noticed how, over the years, Windows
has removed all the programming tools from its system? This keeps the
users helpless. If they want a solution, they have to go out and buy
it. By contrast, every major Linux distribution includes the shell,
perl, python, text editors and thousands of tools for building
solutions. If you need more, there is just about every programming tool
under the sun available for immediate download.A computer is not "easy
to use." That is a marketing myth. A computer is no more easy to use
than a violin, but with much study and practice, both can produce
beautiful music.It all depends on your frame of mind.Every Linux user
should learn something about the history of Unix. The Wikipedia is a
good place to start:http://en.wikipedia.org/wiki/UnixAlso check out
Eric Raymond's The Art Of Unix
Programming:http://www.faqs.org/docs/artu/

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/20/2009 08:45:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] A Brief History Of Printing

[William S. <bs...@pa...>]

The following is an excerpt from my upcoming book, "The Linux Command
Line" due out later this year.To fully understand the printing features
found in Unix-like operating systems, we first have to learn some
history. Printing on Unix-like systems goes way back to the beginning
of operating system itself. In those days, printers, and the way they
were used was much different than today.Printing In The Dim TimesLike
the computers themselves, printers in the pre-PC era tended to be
large, expensive and centralized. The typical computer user of 1980
worked at a terminal connected to a computer some distance away. The
printer was located near the computer and was under the watchful eyes
of the computer’s operators.When printers were expensive and
centralized, as they often were in the early days of Unix, it was
common practice for many users to share a printer. To identify print
jobs belonging to a particular user, a banner page was often printed at
the beginning of each print job displaying the name of the user. The
computer support staff would then load up a cart containing the day’s
print jobs and deliver them to the individual users.Character-based
PrintersThe printer technology of that period was very different in two
respects. First, printers of that period were almost always impact
printers. Impact printers use a mechanical mechanism to strike a ribbon
against the paper to form character impressions on the page. Two of the
popular technologies of that time were daisy wheel printing and
dot-matrix printing.The second, and more important characteristic of
early printers was that printers used a fixed set of characters that
were intrinsic to the device itself. For example, a daisy wheel printer
could only print the characters actually molded into the petals of the
daisy wheel. This made printers of the period much like high-speed
typewriters. As with most typewriters, they printed using monospaced
(fixed width) fonts. This means that each character has the same width.
Printing was done at fixed positions on the page and the printable area
of a page contained a fixed number of characters. Printers, depending
on the model, most likely printed ten characters per inch (CPI)
horizontally and six lines per inch (LPI) vertically. Using this
scheme, a US letter sheet of paper is eighty-five characters wide and
sixty-six lines high. Taking into account a small margin on each side,
eighty characters was considered the maximum width of a print line.
This explains why terminal displays (and our terminal emulators) are
normally eighty characters wide. It’s to provide a WYSIWYG (What You
See Is What You Get) view of printed output using a monospaced
font.Data is sent to a typewriter-like printer in a simple stream of
bytes containing the characters to be printed. For example, to print an
“a”, the ASCII character code 97 is sent. In addition, the low-numbered
ASCII control codes provided a means of moving the printer’s carriage
and paper using codes for carriage return, line feed, form feed and the
like. Using the control codes, it’s possible to achieve some limited
font effects such as bold face by having the printer print a character,
backspace and print the character again to get a darker print
impression on the page.Graphical PrintersThe development of GUIs lead
to major changes in printer technology. As computers moved to more
picture-based displays, so to did printing move from character-based to
graphical techniques. This was facilitated by the advent of the
low-cost laser printer which, instead of printing fixed characters,
could print tiny dots anywhere in the printable area of the page. This
made printing proportional fonts (like those used by typesetters) and
even photographs and high quality diagrams possible.However, moving
from a character-based scheme to a graphical scheme presented a
formidable technical challenge. Here’s why: the number of bytes needed
to fill a page using a character-based printer can be calculated this
way (assuming sixty lines per page each containing eighty
characters):60 X 80 = 4800 byteswhereas, a three hundred dot per inch
(DPI) laser printer (assuming a eight by ten inch print area per page)
requires:(8 X 300) X (10 X 300) / 8 = 900000 bytesThe need to send
nearly one megabyte of data per page to fully utilize a laser printer
was more than many of the slow PC networks could handle, so it was
clear that a clever invention was needed.That invention turned out to
be the page description language (PDL). A page description language is
a programming language that describes the contents of a page. Basically
it says, “go to this position, draw the character ‘a’ in ten point
Helvetica, go to this position...” until everything on the page is
described. The first major PDL was PostScript from Adobe Systems which
is still in wide use today. The PostScript language is a complete
programming language tailored for typography and other kinds of
graphics and imaging. It includes built-in support for thirty-five
standard high quality fonts and the ability to accept additional font
definitions at run time. At first, support for PostScript was built
into printers themselves. This solved the data transmission problem.
While the typical PostScript program was very verbose in comparison to
the simple byte stream of character-based printers, it was much smaller
than the number of bytes required to represent the entire printed
page.A PostScript printer accepted a PostScript program as input. The
printer contained its own processor and memory (often times making the
printer a more powerful computer than the computer it was attached to)
and executed a special program called a PostScript interpreter which
read the incoming PostScript program and rendered the results into the
printer’s internal memory thus forming the pattern of bits (dots) that
would be transferred to the paper. The generic name for this process of
rendering something into a large bit pattern (called a bitmap) is
raster image processor or RIP.As the years went by, both computers and
networks became much faster. This allowed the RIP to move from the
printer to the host computer. This permitted high quality printers to
be much less expensive.Many printers today still accept character-based
streams, but many low-cost printers do not. They rely on the host
computer’s RIP to provide a stream of bits to print as dots. There are
still some PostScript printers too.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/18/2009 04:39:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Today's Site Updates

[William S. <bs...@pa...>]

- Thanks to sharp-eyed readers Dmitry Zhuravlev-Nevsky and Alexander
Wireen, I have corrected a bunch of typos in the "Writing Shell
Scripts" section of the tutorials.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/18/2009 04:14:00 PM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Peanuts And Software

[William S. <bs...@pa...>]

I really enjoy factory tours. I've always had a fascination with how
things work and how things are made. Over the years, I've been on some
great tours, Syracuse China, Corning Glass, Ben & Jerry's Ice Cream,
and best of all, the (now defunct) General Motors assembly plant in
Baltimore.In the past, it seemed like many companies offered tours of
their factories to the public, and why not? The great companies were
truly proud of what they were doing and were happy to show you. This
even applied to products whose production processes are better left
unseen.In recent years, factory tours are getting harder to find. I
don't know the exact reason for this. Maybe its the fear of litigation,
or a desire to keep everything proprietary, I just don't know.The alert
among you may have noticed the story in yesterday's New York Times
announcing that the Peanut Corporation of America has filed for
bankruptcy and will be going out of business. As you may know, Peanut
Corporation of America recently gained notoriety for knowingly shipping
peanut butter to its customers that was contaminated with salmonella
resulting over 600 reported illnesses and 9 deaths. As the scandal
unfolded, reports surfaced of unsanitary conditions in its plants
including cockroaches, leaking roofs, and a report of a dead rat in one
of its peanut roasters.Somehow, I don't think they offered a factory
tour.What does this have to do with software? Plenty. When you make
something in the full light of day, it's a lot less likely that
something horrible is going on under cover of secrecy. Open source code
is like a factory tour for software. You can wander around and feel the
pride of those who created it.Proprietary software is different. What
are they hiding? Does their program have "rats in the roasters?"You'll
never know.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/14/2009 08:45:00 AM

[Linuxcommand-announce] [LinuxCommand.org: Tips, News And Rants] Followup On My Dell Inspiron 530N

[William S. <bs...@pa...>]

Had a problem with the monitor that came with my recently purchased
Dell 530N with Ubuntu. After a couple of hours, the monitor would get
brighter and brighter until it reached maximum brightness and then
after a few minutes of that, the lamp in the monitor would go out
leaving me with a black screen. I could turn the monitor off for a few
minutes (and presumably, let it cool) and it would work for another
couple of hours.I got tired of that (Hey! I'm trying to write a book
here!) so I called Dell's Ubuntu support number (1-866-622-1947) and
got connected to an overseas call center. The representative had me
perform a simple test, reboot the computer and press F2 to get to the
setup screen, then just let it sit and see if the monitor would fail
again. This test would eliminate the possibility of a video driver
issue. Sure enough, after about 30 minutes, it went out again. I called
back and talked to another representative who was able to see what had
transpired during the first call. She arranged for a replacement to be
shipped overnight to me. A refurbished monitor arrived the next
afternoon.I'm pleased with the service. Their support staff was polite
and professional, but I didn't have a chance to test their Linux
skills.Maybe next time.

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Posted By William Shotts to LinuxCommand.org: Tips, News And Rants at
2/13/2009 12:07:00 PM

[Linuxcommand-announce] [LinuxCommand.org: News And Rants] Adding Ubuntu-style sudo To Fedora 10

[William S. <bs...@pa...>]

One of the neat things about Ubuntu is the absence of a discreet user
account for root. This was an unusual idea when it was introduced a
couple of years ago, and I myself, had some initial doubts about it.
But that was then and this is now. I have come to really enjoy this
feature.I recently installed Fedora 10 on one of my test systems and
decided to see what was involved in getting a similar feature in
Fedora.The sudo command is governed by a configuration file
named /etc/sudoers. This file defines the users who are allowed to use
sudo and precisely what commands they are allowed to execute with
elevated privileges. I have written definitions for this before, so I
took a look at the Fedora 10 sudoers files to see how to add myself to
the list of users that can execute any command as root.What I
discovered was that the Fedora 10 sudoers thoughtfully provides the
following lines:## Allows people in group wheel to run all
commands# %wheel ALL=(ALL) ALLThis definition states that any user
belonging to the group wheel will have full access to all commands.
Just what the doctor ordered!So this leaves me with two things to do:
- Uncomment the line in the sudoers file to enable the definition.
- Add myself to the wheel group.The first task is pretty easy. I just
fire up vi (as root) and edit /etc/sudoers. I only need to remove the
leading pound symbol to make the change:## Allows people in group wheel
to run all commands%wheel ALL=(ALL) ALLThe second task is not very hard
either. I bring up the graphical (yes, I'm cheating) user configuration
tool and select my user account and press the "Properties" button, then
select the "Groups" tab on the properties dialog. Scrolling to the
bottom of the list, check the box labeled "wheel":Press OK and we're
done!Here are a couple of questions for all you geniuses out there:
- How would you add yourself to a group using only the command line
tools?
- What is the history and meaning the "wheel" group?Have fun!

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Posted By William Shotts to LinuxCommand.org: News And Rants at
1/29/2009 08:41:00 PM