marți, 23 februarie 2010

Basic Guide for Enterprise Linux® Servers - Red Hat Enterprise Linux 5, CentOS 5, Scientific Linux 5

Finally ready and with the whole support of a lot of people...it's done.
The book is hot and ready containing a lot of ( I'd like to think ) useful information about configuring different type of servers based on Red Hat® Enterprise Linux® 5.
For each chapter I've tried to provide exercises as closer as possible to real life that might help any system administrator to figure out solutions in case problems may occur. Pretty fair, right?

As an addition to the Observation in Chapter 3 page 52 referring to the use of the cat command calling the /dev/urandom device for generating a random set of passwords, allow me to launch this challenge:

How would you generate a set of passwords containing 9 random characters when you want to use all numbers, symbols, and letters of your native language (of course, considering that your keyboard is set appropriately for your native language).

               cat  /dev/urandom | tr -cd " ? " | fold -w ? | head

Replace the question marks with the right expressions and ... check if it works!

miercuri, 10 februarie 2010

Ubuntu UNR (Ubuntu Netbook Remix) 9.10 on Acer Aspire One

I have to say that installing and using UNR 9.10 on my Netbook was quite an experience. A pleasent one, of course.
As I have specified in a previous article using different Debian/Ubuntu Linux based distributions has advantages or disadvantages looking from an user with more or less experience point of view regarding "the Linux stuff" generally speaking.
So, using different pictures of my desktop I'll try to explain what you'll find already installed in this new Canonical Ltd. release and what you'll have to install in case you'll need some more applications.
When your Netbook/Laptop will be powerd up , you'll see something similar to the image above.
The Favorites menu as also all others that follow are customizable.
I'm using my Netbook to keep in touch with family and friends so I've added to Favorites Skype and Pidgin.
I am using my Netbook almost like a portable media player so Banshee, EasyTAG and F-Spot were "a must have" in this menu.
By the way, Banshee organizes your music files and also helps you transfer them into and from your iPod or other portable player you might have.
I don't know if it will work with the iPhone or iPod touch. I don't have one so I can't tell anything about this.
More than this, Banshee will organize and play your Video library too. The AVI format is played perfect by Banshee.
For pictures I have F-Spot. Helps me also with the transfer of pictures from my photo camera.
The gFTP application added here is useful for me to upload/download files into/from my home server and also into/from other computers in my home network. Simple application and very easy to use.
The next menu is Files &Folders.
You can see here how I have organized my folders and where I'm keeping my stuff.
In Volumes area of this menu you notice one of my partitions that was mounted separately. Kinda like the D:\ drive in Windows.
What follows next reflects infact how Debian/Ubuntu Linux based distributions keep organized their menus and applications.

I know, it's odd to see here the CD/DVD Creator application for my Netbook but from time to time I'm using an external DVD burner ...eh.. old habits die hard I guess.
You don't have to navigate up to this menu and select Take Screenshot if you ever need to take a screenshot of your desktop.
You can do this fast if you hit the Print Screen button on your keyboard. It's already linked to this application.

In the Graphics section you notice the GIMP.
This application is not installed by default so you'll have to install it by yourself pretty easy using the Synaptic Package Manager located in System menu under the Administration section.
When you'll install the GIMP be sure you'll install also all necessary plugins requested if you have a scanner or a multifunctional  that you'd like to use with your computer.
Shortly saying , the GIMP is similar to Adobe Photoshop doing the same thing but IT IS FREE software!

The Internet menu organizes speciffic programs.
What is NOT installed by default: gFTP,
Pidgin, Skype, Java.
I had to install these applications manually with the Synaptic Package Manager.
Instead of Pidgin you'll have installed by default as "messenger" another application called Empathy which looks and does the same thing as Pidgin but ... I like Pidgin more.
You can uninstall Empathy also using the Synaptic Package Manager. Just select it there and choose Mark For Removal or Mark for Complete Removal then click Apply.
Skype was installed from their home webpage. Just Download the appropriate Ubuntu 32 bit package into your computer then double click on it . It will be installed in a jiffy.

Now I can talk about the reason why a few months ago I was so excited about Linux Mint 7 then about Linux Mint 8 and now I end up using UNR 9.10.
Well, everything was about Skype, Pulseaudio and my Bluetooth headset (you've noticed probably the little Bluetooth icon on the upper right corner of my screenshots).

It's a long storry but if you'll ever get into the same problems read this so you won't waste your time in the future.
Here it is: I'm using Skype a lot and I like to use my Bluetooth headset with it.
I also like to listen to my brutal heavy metal music and I like to use my Bluetooth headseat for this ( well, for me this is not optional but mandatory while people around me don't have the same feelings about this music... I guess they have something against good art! hahahahahaha).
Linux Mint 7 comes with Pulseaudio sound server. You can also uninstall Pulseaudio in Linux Mint 7 loosing  a lot of applications that depends on it ( sound and video players especially!) but there is no problem because Linux Mint repositories offers you other applications instead that don't need Pulseaudio.
Linux Mint 7 + Pulseaudio + Skype + Bluetooth headset = a lot of trouble and time wasted to make all together work.
Finally I had to uninstall Pulseaudio to determine Skype to get ridd of the only option in it's sound options that was Pulseaudio.

Once Pulseaudio away from my computer, I had to find a script, customized it a little bit  and then installed it into my Netbook to be able to use my head seat but unfortunately sound ONLY without voice. Fair enough but not justifying those 40 dollars payed for my Bluetooth Sony headset.
Good, now after all this , Skype displayed in it's sound menu a lot of other options and even if I couldn't use the microphone from my headseat at least I could talk using the microphone of my Netbook.

Wait, wait , wait! The story is not over yet.
Then Linux Mint 8 came out so I was all so damn excited about it that I have installed it without even trying. Big mistake because this time when I have removed Pulseaudio I have lost not only Audio/Movie players but whatever was necessary for my laptop to produce some noize: the sound !
That ment that in Linux Mint 8 Pulseaudio was the default sound system!!

After a whole day and a night and another morning all lost to find some work arounds for this problem and also after a lot of cursings in languages that I didn't even know that I was able to think ( or speak )....I GAVE UP! I surrendered so ...back to Linux Mint 7 and all that work again!

Until a few days ago when I've decided to see what's all about the UNR 9.10.
Especially because they said it's lightweight.
All I had to do was to plugin my Cirago USB dongle Mini into my Netbook, push the sync button on my headset and using the Bluetooth application synchronizing the headset with my computer.

I was about to die two times: first when I discoverd Pulseudio the default sound system also here in UNR 9.10 and second when I saw that Pulseaudio recognized my headset without any additional workaround or script as I told you before.
More than that, Pulseaudio gave me this time the possibility to choose between full duplex (but lower sound quality when in a conversation ) sound + voice and high quality ( no voice) while listening to my music through Rhythmbox or Banshee!!!!!
So now I am using Skype + Pulseaudio+ Full features Bluetooth headset with UNR 9.10. HOOOOOOOOO-YAAA!!!!

Back to some more screenshots now!
In the Office menu you see the Adobe Reader 9 which I've manually installed.
If you want only to read the PDF documents Evince is enough and it is installed by default.
You see here the hole OpenOffice stuff,
another nice "gizmo" which in UNR 9.10 comes with it's version 3.1 that FINALLY OPENS that sensless (at least for me) format named .docx !!!!

Next screenshot presents the Sound& Video menu.
Banshee is not installed by default. I just gave it a try and I like how it works in UNR.
Rhythmbox came by default but I uninstalled it once I saw Banshee at work.


An important note for the sound and video stuff: if you want to play the .mp3 format files you have to install by yourself using again the Synaptic Package Manager the appropriate plugins. UNR will not provide this stuff by default due to all that approprietary software thing bla-bla-bla-I-sue-you-halt-das-ist-mine-scheize.


In addition I've also installed the EasyTAG application that helps me write tags and correct names of my mp3 music files so Banshee (or Rhythmbox) will transfer them and organize them in the same order and in the same "folder" into my iPod.
The last menu -System- is the most complex one and refers to all kind of settings you'll want to apply to your
computer ( Preferences section ) and also useful system-tools ( to use them you'll need administrative password) in Administration section.

All icons you saw in different menus could be placed with a simple click also in the Favorites menu but....why bother if you can do something more elegant.
Notice the Keyboard Shortcuts icon in this section, click on it and you'll figure out how how to create keyboard shortcuts to any application you want without navigating all those menus and searching for the application you wanna use.
For example, Alt+W opens in my computer Firefox , Alt+E opens the mail, Alt+B opens Banshee, Alt+T opens a terminal, and so on.
To be honest I don't remember when was last time I used the mouse for my laptop!