Ubuntu Tutorials

I was spending some time in the Ubuntu Forums this evening and thought I would share a few questions that I ran into. For those of you looking for a high-level tutorial this isn’t it, but its a good tip for anyone.

If you need to convert audio formats there are a few options for you. I have long used soundconverter to go between just about any format out there. I recently even converted a very large .mp3 collection to .ogg.

To install soundconverter simply use:

Applications > Add/Remove > Search:"soundconverter"

sudo aptitude install soundconverter

I hope this helps. Now that you’ve got a converter why not switch your .mp3 over to the FOSS .ogg format?   Note: you may need the appropriate codecs to read / convert these audio formats.  You might want to check out my previous post How to install multimedia codecs.

Ubuntu Tutorials Presents – Ubuntu Book of the Week

I’ve had tutorials coming out my ears lately and I realize that many of them are written for use on the command line. For many of you the command line may be intimidating, especially if you’re more accustomed to the Windows standard GUI. I want to tell you the command line can be a VERY powerful tool if you just learn a few basic things. Please don’t consider the command line a crutch or “Linux is hard because you have to type commands”. You can do everything via a GUI that you can do via the command line, it is simply easier or quicker to do it the latter way.

Below are a few basic command for those of you new to the command line:

ls - list contents of a directory
sudo - "super-user do" (grants administrator rights)
cd - change directory
aptitude - APT package management system (update, install, remove, search)
clear - clear screen
chmod - change file access permissions
chown - change file and group ownership
cp - copy
mv - move
rm - remove
cat - concatenate files (dump to screen)
nano - basic text editor
vi - advanced text editor
fdisk - partition table manipulator
df - disk free (remaining / used disk space)
users - users currently logged in
useradd - add a user
usermod - modify existing user
uname - show system data (try uname -a)
mount - mount a file system, cd or removable drive
umount - un-mount a file system, cd or removable drive
top - show current running processes
touch - create new, empty, file
reboot - reboot your system
shutdown - shutdown your system
passwd - change user password
ping - ping a network device or location (ping google.com)
more - show output one screen at a time
exit - logout of the terminal
eject - eject a cdrom or removable device

There are many, many more commands that you can take advantage of. This is just a short list of some of the more commonly used commands. If anyone has suggestions on adding to this list I would appreciate feedback.

Also, if you’re unsure the proper usage of one of these commands simply use the “man” (manual) pages to read more about it. Use the command: man [command] to find out the details on usage and syntax. I hope this helps!

I was reading tonite about the Apache module, mod_security, which allows you to tighten down the security of your web server. I will admit that I am not a pro with mod_security and I welcome any tips & tricks that the rest of you have. For the rest of you, if you are running a web server on an Ubuntu machine you can tighten a few things down by installing the mod_security module.

Installation

sudo aptitude install libapache2-mod-security

a2enmod mod-security

sudo /etc/init.d/apache2 force-reload

The first command installs the mod_security module. The second command enables the module within Apache, and the third restarts your Apache server to take advantage of the newly added module.

Configure

We’ll now need to set some rules. Below I have an example rules file which should work for most of you. Again, if you do have suggestions on expansions or revisions for this configuration please leave a comment. You can append these rules to the end of your current Apache configuration.

sudo gedit /etc/apache2/apache2/conf

Add the following to the end of the file

<IfModule mod_security.c>

# Turn the filtering engine On or Off

SecFilterEngine On

# Make sure that URL encoding is valid

SecFilterCheckURLEncoding On
# Unicode encoding check

SecFilterCheckUnicodeEncoding Off

# Only allow bytes from this range

SecFilterForceByteRange 0 255

# Only log suspicious requests

SecAuditEngine RelevantOnly

# The name of the audit log file

SecAuditLog /var/log/apache2/audit_log

# Debug level set to a minimum

SecFilterDebugLog /var/log/apache2/modsec_debug_log

SecFilterDebugLevel 0

# Should mod_security inspect POST payloads

SecFilterScanPOST On

# By default log and deny suspicious requests

# with HTTP status 500

SecFilterDefaultAction "deny,log,status:500"

</IfModule>

After adding these rules we’ll again need to restart the Apache server to make use of them. You can restart the Apache server using:

sudo /etc/init.d/apache2 restart

I hope this helps in securing your web server. I have had my server hacked on a couple of occasions and each time has taught me something more about security. It doesn’t have to be difficult or complicated and a little bit of security preparation really goes a long way.

For more information on mod_security, configuration and options see the links below:

Secure your Apache with mod_security – HowtoForge

Secure your Apache2 with mod-security – Debuntu.org

modsecurity.org

technorati tags:apache, apache2, mod_security, ubuntu, server, web, security

I have been considering a domain transfer for this site for some time and today I finally put in the time to actually do it. If you haven’t already noticed you should have automagically been redirected to the new domain ubuntu-tutorials.com. Please forgive the dust while I finish the transition. I think I have taken care of all of the popular pages so far.

Most links should auto-redirect so if you are currently linking to me you shouldn’t have to worry.  If you find a link that doesn’t resolve to the correct content please let me know.

Thank You

I found a sweet tutorial this morning that I really wanted to share with the rest of you. gnome-open, shared by the ubuntonista, is a sweet little command that auto-associates whatever you’re trying to do with the proper file/mime type. From what I see it resembles the universal “open” command on OSX. Here are a few examples of how you can use gnome-open:

To quickly visit google.com:

gnome-open google.com

To shoot off an email to someone:

gnome-open mailto:someguy@thatplace.org

To quickly open a location in Nautilus:

gnome-open ~/my-folder

Open a document with:

gnome-open document.odf

…and I think you get the idea. gnome-open will open anything for you with the right program. Gotta love that.

technorati tags:gnome, ubuntu, linux, gnome-open, tutorial, edgy

I recently read an article on Slashdot mentioning how MySpace users generally have more secure passwords than those in corporate environments. This reminded me of a simple password generator that Ubuntu has to make sure you’re using a password nearly unbreakable. (note: no password is completely unbreakable, but using a generator such as this sure does step up the level of security.)

The password generator program that I use is pwgen. You can install pwgen using the following:

sudo aptitude install pwgen

Once this is installed you can simply use the command pwgen on the command line to dump out a screenful of secure passwords. Why a screenful? I wondered that as well but it does make sense. If the passwords were generated one at a time it would be possible for someone to see or find in your history. With a screen dump of password suggestions you can safely select one yourself and update your password from memory.

For some added security you can use a few variables when running pwgen. To include upper and lowercase characters use:

pwgen -c

To include numbers in your password use:

pwgen -n

There is also an option which the developers consider ultra-secure. These are supposed to be completely random, hard-to-memorize password generally suggested for machines. These include both upper and lower case, pluse numbers. They are also very difficult to remember in most cases. If you’d like something ultra-ultra secure (and I hope you have a good memory) use:

pwgen -s

I hope this helps those security aware out there. The password is often the first and last line of defense on our systems. If any of you have other suggestions for generating random, secure passwords please leave a comment. I am interested in other solutions.

If you’d like even more security and want more than just a “password” check out my buddy Aaron’s post Secure Passphrases

technorati tags:ubuntu, linux, dapper, edgy, password, generator, security, random

DVD playback is not a feature that is installed by default due to license restrictions. In my opinion the restriction is stupid, very restrictive and violates my rights (of course I am not a lawyer so don’t listen to my rants.) This tutorial will show you how to install DVD playback capability on your Ubuntu linux machine.

note: in some areas this is not legal. If that is the case for you you can 1) continue to let some corporation demand payment to be able to playback the DVDs you already paid for, 2) stop watching DVDs altogether or 3) tell them to take a hike and install playback anyway. Viva la revolucion!

Installing DVD playback is pretty simple. You’ll need to install the Seveas Repository before you’ll have access to it and then simply run:

sudo aptitude install libdvdcss2

or, if you prefer not to install Seveas repository you can run the following command to automagically download and install the appropriate files:

sudo /usr/share/doc/libdvdread3/./install-css.sh

We desperately need a change to our countries laws in this regard, at least in the US. Until then we simply do what has to be done.

update: if you find that, for whatever reason, you don’t have the above file to run and install you can try to take a look at this comment for an additional method. install libdvdread3

technorati tags:ubuntu, dvd, playback, libdvdcss2, libdvdcss, breezy, dapper, edgy

The Situation
It has come to our attention that a small portion of nvidia users are experiencing a failure to boot into X after today’s kernel update.

The problem seems to only happen on some specific configurations involving the unofficial 9631 driver installations and does not appear to affect 877x from the official repositories.

Symptoms:
After applying today’s updates and rebooting, the graphical environment does not initialize. You may get a blue screen with an error dialog or just an empty black screen.

If you’ve applied the updates and rebooted and you can get to a graphical login prompt, you are not affected by this issue..

Affects:
This seems to mostly affect people using NVidia driver version 9631 on Edgy Eft. Users using both manually installed and unofficial linux-restricted-modules repositories seem to report this problem.

This doesn’t seem to affect those using official nvidia 8xxx drivers from the repositories, or those who are using 9640 beta drivers or higher.

UPDATE: One user states that it he is experiencing this issue with the official NVIDIA Legacy drivers too.

This issue does not appear to be as widespread as the problem that happened to Dapper a few months back.

Cause:
The root cause is currently unknown and under investigation. It seems to stem from several key nvidia driver files apparently being removed during the update process. these files include:
Code:

/usr/lib/xorg/modules/drivers/nvidia_drv.o /usr/lib/xorg/modules/libglx.soThis issue appears difficult to reproduce consistently. I am still investigating trying to find a root cause for why those files would be removed by the update process.

Solutions and Workarounds:
Currently, the solution/workaround involves reinstalling the nvidia drivers. If you installed these nvidia drivers by adding a repository to /etc/apt/sources.list and performing a system update, please issue the following command:
Code:

sudo apt-get install --reinstall linux-restricted-modules-$(uname -r) nvidia-glxIf you installed nvidia drivers from an executable downloaded from nvidia.com, please follow the instructions for installing that driver again.

In either case, running this command sometimes has good results, too:
Code:

sudo depmod -aeAgain, details are just beginning to unfold about this issue.

On behalf of everyone here at Ubuntu, I apologize for any inconvenience this may have caused you.

(original post by #kubuntu-devel)

Previously I did a post on How to Install Microsoft Core Fonts on Ubuntu packages for compatibility with the fonts everyone else seems to be using. Of course, as an Open Source Advocate, I prefer to use the non-proprietary fonts but there do arise situations where many of us need compatibility so we’ve got to bend occasionally. This post is an addition to the previous, only this time I’ll outline how to convert and install fonts from your mac-based machine for use on Ubuntu.

First of all you need a quick program to convert the fonts because Mac embeds extra junk information in the fonts themselves. This’ll allow Ubuntu to read the font information and let you use them on your machine.

sudo aptitude install fondu

After this is installed simply copy your mac-based fonts into a folder and convert them using:

fondu * (or fondu <filename>)

Put these newly converted fonts into your fonts directory (~/.fonts) or, while inside the Nautilus file manager type CTRL-L to “Open Location” and type “fonts:///” You can also drag-drop your fonts into either location.

Between these last two posts you should have just about every font you’d ever need!