Showing posts with label LINUX. Show all posts
Showing posts with label LINUX. Show all posts

Linux interview questions and Answers



                        Now I am going to start a new post which will be updated on timely basis , helpful for the guys who are preparing for interview in Linux field....


1.What are the main difference from LINUX and WINDOWS ?


  1. Linux is an open source software and Windows is a closed source software.
  2. Because Linux is an open source software so whenever a users faces a threat or problem he report the same on community discussion form and developers starts to finding the solution. While Windows OS takes 2 to 3 month for correction of reported threat and error and after that releases new patches and updates.
  3. Linux OS is most secure than Windows OS.
  4. Linux systems are well known for their ability to run for years without failure
  5. Linux also handles a large number of processes running at once much better than Windows does--that's something, in fact, that tends to degrade Windows' stability quickly.

Linux Tricks & Hacks

1. Runnig top command in batch mode

Top is a very useful command we are using while working with linux for monitoring the utilization of our system.It is invoked from the command line and it works by displaying lots of useful information, including CPU and memory usage, the number of running processes, load, the top resource hitters, and other useful bits. By default, top refreshes its report every 3 seconds.
Most of us use top in this fashion; we run it inside the terminal, look on the statistics for a few seconds and then graciously quit and continue our work.
But what if you wanted to monitor the usage of your system resources unattended? In other words, let some system administration utility run and collect system information and write it to a log file every once in a while. Better yet, what if you wanted to run such a utility only for a given period of time, again without any user interaction?
There are many possible answers:
  • You could schedule a job via cron.
  • You could run a shell script that runs ps every X seconds or so in a loop, incrementing a counter until the desired number of interactions elapsed. But you would also need uptime to check the load and several other commands to monitor disk utilization and what not.
Instead of going wild about trying to patch a script, there's a much, much simpler solution: top in batch mode. 
top can be run non-interactively, in batch mode. Time delay and the number of iterations can be configured, giving you the ability to dictate the data collection as you see fit. Here's an example:

top -b -d 10 -n 3 >> top-file

We have top running in batch mode (-b). It's going to refresh every 10 seconds, as specified by the delay (-d) flag, for a total count of 3 iterations (-n). The output will be sent to a file. A few screenshots:
And that does the trick. Speaking of writing to files ...

2. Write to more than one file at once with tee

In general, with static data, this is not a problem. You simply repeat the write operation. With dynamic data, again, this is not that much of a problem. You capture the output into a temporary variable and then write it to a number of files. But there's an easier and faster way of doing it, without redirection and repetitive write operations. The answer: tee.

tee is a very useful utility that duplicates pipe content. Now, what makes tee really useful is that it can append data to existing files, making it ideal for writing periodic log information to multiple files at once.

Here's a great example:
ps | tee file1 file2 file3
That's it! We're sending the output of the ps command to three different files! Or as many as we want. As you can see in the screenshots below, all three files were created at the same time and they all contain the same data. This is extremely useful for constantly changing output, which you must preserve in multiple instances without typing the same commands over and over like a keyboard-loving monkey.

Now, if you wanted to append data to files, that is periodically update them, you would use the -a flag, like this:
ps | tee -a file1 file2 file3 file4

3. Unleash the accounting power with pacct

Did you know that you can log the completion of every single process running on your machine? You may even want to do this, for security, statistical purposes, load optimization, or any other administrative reason you may think of. By default, process accounting (pacct) may not be activated on your machine. You might have to start it:
/usr/sbin/accton /var/account/pacct
Once this is done, every single process will be logged. You can find the logs under/var/account. The log itself is in binary form, so you will have to use a dumping utility to convert it to human-readable form. To this end, you use the dump-acct utility.
dump-acct pacct
The output may be very long, depending on the activity on your machine and whether you rotate the logs, which you should, since the accounting logs can inflate very quickly.
And there you go, the list of all processes ran on our host since the moment we activated the accounting. The output is printed in nice columns and includes the following, from left to right: process name, user time, system time, effective time, UID, GID, memory, and date. Other ways of starting accounting may be in the following forms:
/etc/init.d/psacct start
Or:
/etc/init.d/acct start
In fact, starting accounting using the init script is the preferred way of doing things. However, you should note that accounting is not a service in the typical form. The init script does not look for a running process - it merely checks for the lock file under /var. Therefore, if you turn the accounting on/off using the accton command, the init scripts won't be aware of this and may report false results.
BTW, turning accounting off with accton is done just like that:
/usr/sbin/accton
When no file is specified, the accounting is turned off. When the command is run against a file, as we've demonstrated earlier, the accounting process is started. You should be careful when activating/deactivating the accounting and stick to one method of management, either via the accton command or using the init scripts.

4. Dump utmp and wtmp logs

Like pacct, you can also dump the contents of the utmp and wtmp files. Both these files provide login records for the host. This information may be critical, especially if applications rely on the proper output of these files to function.
Being able to analyze the records gives you the power to examine your systems in and out. Furthermore, it may help you diagnose problems with logins, for example, via VNC or ssh, non-console and console login attempts, and more.
You can dump the logs using the dump-utmp utility. There is no dump-wtmp utility; the former works for both.

You can also do the following:
dump-utmp /var/log/wtmp
Here's what the sample file looks like:

5. Monitor CPU and disk usage with iostat

Would you like to know how your hard disks behave? Or how well does your CPU churn?iostat is a utility that reports statistics for CPU and I/O devices on your system. It can help you identify bottlenecks and mis-tuned kernel parameters, allowing you to boost the performance of your machine.
On some systems, the utility will be installed by default. Ubuntu 9.04, for example, requires that you install sysstat package, which, by the way, contains several more goodies that we will soon review:
Then, we can start monitoring the performance. I will not go into details what each little bit of displayed information means, but I will focus on one item: the first output reported by the utility is the average statistics since the last reboot.
Here's a sample run of iostat:
iostat -x 10 10
The utility runs 10 times, every 10 seconds, reporting extended (-x) statistics. Here's what the sample output to terminal looks like:

6. Monitor memory usage with vmstat

vmstat does the similar job, except it works with the virtual memory statistics. For Windows users, please note the term virtual does not refer to the pagefile, i.e. swap. It refers to the logical abstraction of memory in kernel, which is then translated into physical addresses.
vmstat reports information about processes, memory, paging, block IO, traps, and CPU activity. Again, it is very handy for detecting problems with system performance. Here's a sample run of vmstat:
vmstat -x 10 10
The utility runs 10 times, reporting every 1 second. For example, we can see that out system has taken some swap, but it's not doing anything much with it, there's approx. 35MB free memory and there's very little I/O activity, as there are no blocked processes. The CPU utilization spikes from just a few percents to almost 90% before calming down.
Nothing specially exciting, but in critical situations, this kind of information can be critical.

7. Combine the power of iostat and vmstat with dstat

dstat aims to replace vmstat, iostat and ifstat combined. It also offers exporting data into .csv files that can then be analyzed using spreadsheet software. dstat uses a pleasant color output in the terminal:
Plus you can make really nice graphs. The spike in the graph comes from opening the Firefox browser, for instance.

8. Collect, report or save system activity information with sar

sar is another powerful, versatile system. It is a sort of a jack o' all trades when it comes to monitoring and logging system activity. sar can be very useful for trying to analyze strange system problems where normal logs like boot.msg, messages or secure under /var/log do not yield too much information. sar writes the daily statistics into log files under /var/log/sa. Like we did before, we can monitor CPU utilization, every 2 seconds, 10 times:
sar -u 2 10
Or you may want to monitor disk activity (10 iterations, every 5 seconds):
sar -d 5 10
Now for some really cool stuff ...

9. Create UDP server-client - version 1

Here's something radical: create a small UDP server that listens on a port. Then configure a client to send information to the server. All this without root access!

Configure server with netcat

netcat is an incredibly powerful utility that can do just about anything with TCP or UDP connections. It can open connections, listen on ports, scan ports, and much more, all this with both IPv4 and IPv6.
In our example, we will use it to create a small UDP server on one of the non-service ports. This means we won't need root access to get it going.
netcat -l -u -p 42000
Here's what we did:
-l tells netcat to listen, -u tells it to use UDP, -p specifies the port (42000).
We can indeed verify with netstat:
netstat -tulpen | grep 42000
And we have an open port:

Configure client

Now we need to configure the client. The big question is how to tell our process to send data to a remote machine, to a UDP port? The answer is quite simple: open a file descriptor that points to the remote server. Here's the actual BASH script that we will use to test our connection:
The most interesting bit is the line that starts with exec.
exec 104<> /dev/udp/192.168.1.143/$1
We created a file descriptor 104 that points to our server. Now, it is possible that the file descriptor number 104 might already be in use, so you may want to check first with lsof or randomize the choice of the descriptor. Furthermore, if you have a name resolution mechanism in place, you can use a hostname instead of an IP. If you wanted to use a TCP connection, you would use /dev/tcp.
The choice of the port is defined by the $1 variable, passed as a command-line argument. You can hard code it - or make everything configurable by the user at runtime. The rest of the code is unimportant; we do something and then send information to our file descriptor, without really caring what it is. Again, we need no root access to do this.

Test connection

Now, we can see the server-client connection in action. Our server is a Ubuntu 8.10machine, while our client is a Fedora 11. We ran the script on the client:
And watch the command-line on the server:
To make it even more exciting, I've created a small Flash demo with Wink. You are welcome to play the file, if you're interested:

Cool, eh?

10. Configure UDP server-client - version 2

The limitation with the exercise above is that we do not control over some of the finer aspects of our connection. Furthermore, the connection is limited to a single end-point. If one client connects, others will be refused. To make things more exciting, we can improve our server. Instead of using netcat, we will write one of our own - in Perl.
Perl is a powerful programming language, very flexible, very neat. I must admin I have only recently began dabbling in it, so do not expect any miracles, but here's one way of creating a UDP server in Perl - there are tons of other implementations available, better, smarter, faster, and more elegant.
The code is very simple. First, let's take a look at the entire file and then examine sections of code. Here it is:
#!/usr/bin/perl

use IO::Socket;

$server = IO::Socket::INET->new(LocalPort => '50060',
                                Proto => "udp")
or die "Could not create UDP server on port
$server_port : $@n";

my $datagram;
my $MAXSIZE = 16384; #buffer size

while (my $data=$server->recv($datagram,$MAXSIZE))
{
    print $datagram;

    my $logdate=`date +"%m-%d-%H:%M:%S"`;
    chomp($logdate);

    my $filename="file.$logdate";
    open(FD,">","$filename");
    print FD $datagram;
    close(FD);
}

close($server);
The code begins with the standard Perl declaration. If you want extra debugging, you can add the -w flag. If you want to use strict code, then you may also want to add use strict;declaration. I warmly recommend this.
The next important bit is this one:
use IO::Socket;
This one tells Perl to use the IO::Socket object interface. You can also use IO:Socket::INET specifically for domain sockets. For more information, please check the official Perl documentation.
The next bit is the creation of the socket, i.e. server:
$server = IO::Socket::INET->new(LocalPort => '50060',
                                Proto => "udp")
or die "Could not create UDP server on port
$server_port : $@n";
We are trying to open the local UDP port 50060. If this cannot be done, the script will die with a rather descriptive message.
Next, we define a variable that will take incoming data (datagram) and the buffer size. The buffer size might be limited by the network implementation or network restrictions on your router/switch or the kernel itself, so some values might not work for you.
And then, we have the server doing some hard work. It prints the data to the screen. But it also creates a log file with a time stamp and prints the data to the file as well.
The beauty of this implementation is that the server permits multiple incoming connections. Of course, you will have to decide how you want to differentiate the data sent by different clients, whether by a message header or using additional IO:Socket:INET objects like PeerAddr.
On the client side, nothing changes.

Conclusion

That's it for now. This crazy collection should help you impress friends evoke a smile with your peers or even your boss and help you be more detailed and productive when it comes to system administration tasks. Some of the utilities and tricks presented here are tremendously useful.
If you're wondering what distribution you may need to be running to get these things done, don't worry. You can get them working on all distros. Throughout this document, I demonstrated using Ubuntu 8.10, Ubuntu 9.04 and Fedora 11. Debian-based or RedHat-based, there's something for everyone.

Best Linux OS in 2012


1. Ubuntu 12.04 LTS

Best Linux OS in 2012

Ubuntu is the #1 and the most popular distro out there. Even though Linux Mint appeals more to new users Ubuntu has a rigorous release cycle and tends to have more features implemented in each release. Ubuntu does not come with a load of software and codecs pre installed like Linux Mint. So new users may have trouble playing certain media formats and may require a few command line installations but due to the excellent community support they can be sorted out within minutes.
2. Linux Mint 13
Best Linux OS in 2012

Linux Mint is known as the second most popular linux distribution simply because of its user friendliness. It comes with loads of software carefully picked by the team, media codecs and drivers. The distro works so well out of the box you will not be spending any time trouble shooting. The Distro focuses on what is best for its users and provides what the mainstream linux users demand (most of the time). Linux Mint 13 comes in 2 editions. The Cinnamon edition includes a modern Gnome 3 desktop with a familiar and traditional layout. The MATE edition comes with a Gnome 2 desktop. Compared to the cinnamon edition, the MATE edition is more stable but is quite boring. Cinnamon is a fairly new desktop that is being developed by the mint team.
Linux mint is based on Canonical's Ubuntu.

3. Pinguy OS 12.04 LTS

Best Linux OS in 2012

Pinguy OS is an Ubuntu based distribution that comes with A LOT of software preinstalled. It is great for users who want to explore the extensive software that Linux has to offer. It is also very convenient because it includes almost all the software that a user may require. Pinguy OS is a fairly new distro but it is gaining popularity quickly. Pinguy OS includes two Docks by default and the overall look of the desktop leans toward OS X. Pinguy OS 12.04 includes a customized gnome-shell.
4. Zorin OS
Best Linux OS in 2012

Zorin OS is optimized for users who are transitioning From windows. It looks quite similar to Windows 7 and comes with "zorin look changer" that can make your desktop look similar to older Windows versions and Mac OS X. Zorin OS also offers four premium versions (Ultimate, Business, Multimedia, Gaming) which are available upon donating. There is also a free version that does not come with as much software preinstalled.

5. Peppermint OS 3

Best Linux OS in 2012

Peppermint OS a very light distro that comes with LXDE desktop envioronment. LXDE is very simple to use and many will find it to be a straightforward DE. The OS boots up quite fast which makes it ideal for older computers or netbooks. Peppermint OS 3 is based on Lubuntu 12.04. It includes an elegant theme by default and includes media-codecs out of the box.

6. Fedora

Best Linux OS in 2012

You simply cant go wrong with Fedora ( or Red Hat Enterprise Linux for a more server oriented usage ). The quality of Red Hat Linux distributions, and a great looking desktop. Perhaps a little less user-friendly than the two previous Debian based Linux distributions mentioned above. 







Best Linux desktop of 2012: Linux Mint 13

Best Linux desktop of 2012: Linux Mint 13
Best Linux desktop of 2012: Linux Mint 13

The very popular Linux distribution, Mint, has a new version Linux Mint 13, Maya, and a new take on the GNOME 3.x desktop interface: Cinnamon 1.4. The result is, in my opinion, the best Linux desktop for experienced users to date.
Not everyone will agree this. They'll find Mint's other default desktop MATE to be much more their speed. MATE is a fork of that old Linux desktop favorite, GNOME 2.x. While I haven't looked at the MATE edition of GNOME closely, other Linux reviewers, like Jim Lynch, have and Lynch likes what he's seen of Mint 13 paired with MATE.
Even with the little work I've done with MATE though I can see what GNOME 2.x fans will like it. It's a very clean desktop and it feels and works like a natural extension of GNOME 2. GNOME fans who abandoned GNOME after the annoying changes in GNOME 3.x for Lightweight X11 Desktop Environment (LXDE) will want to give Mint with MATE a try. With MATE, GNOME 2.x is back.
That said, I prefer Cinnamon myself. Cinnamon, which is remindful of GNOME 2.x, is built on Clutter and Gnome 3. I find it more attractive and I like its features. For example, the menu includes drag and drop support. With that, besides just being move icons from the menu to the desktop, I can add them to panel launchers, favorites, and reorder my favorites. I can also right-click the menu to use the menu editor to change edit the main menu itself. It's pretty, gives me great control over how my desktop, and now
Another great feature is Cinnamon's new Expo mode is. Expo gives you great control over your workspaces. You can choose how many workspaces to use and drag and drop applications to each workspace. It's a powerful tool but as easy to use as Mac OS X Lion's Mission Control and Spaces.
Much as I'd like to recommend Cinnamon for everyone though, I can't. As Mint's own developers admit that while, "Cinnamon is among the sleekest and most modern looking environments [and] features innovative features and emphasis on productivity with traditional desktop metaphors, it also has several problems. These are:
Cons:
  • Cinnamon requires 3D acceleration and might not work well for you, depending on your graphics card and/or drivers.
  • Cinnamon is brand new and unfortunately not yet as stable as more matures and established desktops such as MATE, KDE or Xfce.
  • Cinnamon relies on Gnome 3 and Clutter, which are also both brand new and going through rapid transformations.
Of course, you can just switch between MATE and Cinnamon. One of Mint's new features is an improved version of the old Gnome Display Manager: MDM. With MDM, you can pick which GUI to boot into, configure them, set up themes for them, and set up remote, automatic, and timed logins. There may be display/login manager with more features out there, but I honestly don't know what it could be though.
For me, however, Cinnamon works just fine. I tested Mint 13 with Cinnamon on two systems. The first was one of my workhorse Dell Inspiron 530S. This system is powered by a 2.2-GHz Intel Pentium E2200 dual-core processor with an 800-MHz front-side bus. This PC has 4GBs of RAM, a 500GB SATA (Serial ATA) drive, and an Integrated Intel 3100 GMA (Graphics Media Accelerator) chip set. I also put it to work on my new Lenovo ThinkPad T520 laptop. This, much more up-to-date computer boasts a 2.5GHz Intel Core i5 Processor, 4GBs of RAM, a 500GB hard drive and an integrated Intel HD Graphics 3000 processor. On both systems, the old and new, Linux Mint and Cinnamon ran flawlessly.
Installing Mint, as always, is a snap. All you need do is download the Mint ISO, burn it to a CD, DVD, or USB stick and then re-boot your computer with it and follow the instructions. On my PCs, the entire process took less than half-an-hour. Mint will run on pretty much any PC. It requires only 512MBs of RAM, but runs better with at least 1GB of memory.
The only annoying thing about the process is you can't do an in-place update of Mint 13 from Mint 12 or any other Linux distribution. That's by design. Mint's developers feel that you'll avoid out of date software incompatibilities by forcing you to do a fresh install. That's true, but it also means you may need to back up and restore your home directories and files. I did this by backing them up to an attached USB drive.
Moving on to the operating system itself, Mint 13 is based onUbuntu 12.04. I like this version of Ubuntu with its Unity interface as well. In particular I think Ubuntu 12.04 is great for users who aren't computer savvy. But, I'm a Linux pro. I like operating systems that enable me do decide exactly what I want it to do and how it's going to do it. If you're a power user too, then you'll like the taste of Mint.
Beneath the desktop, you'll find a Linux 3.2 kernel. Mint, like most Linux distributions, is still using ext4 for its file system.
Above that foundation, in applications, you'll find the usual Linux distribution goodness: LibreOffice 3.5.2 for office work, Firefox 12 for the Web browser; GIMP 2.6.12 for graphics; Thunderbird 12.01 for e-mail; and Pidgin 2.10.3 for IM. I'm not crazy about the choices of Thunderbird, I much prefer Evolution for e-mail or Firefox over Chrome.
The default software choice is no big deal though since Mint's Software Manager makes adding new programs a snap. The one quirk here is that after you install the program from the Software Manager the screen doesn't show it as being installed. You need to leave the program installation screen and come back to it before you'll see that your software was indeed installed. It's not a big bug, but it's a bit of a nuisance and I can see someone thinking they really hadn't installed a program when they've actually done so.
As has long been the case with Mint, and it's first claim to fame, this is one Linux distribution that comes ready to deal with proprietary video and audio codexes such as Flash, MP3 and DVDs. Ironically, thanks to including VLC Media Player 2.01, Linux Mint plays DVDs better than Windows 8 will. You see, Mint comes ready to play DVDs. In Windows 8, DVD playback is an extra-cost item.
It's not any of these components by themselves that really impress me. I mean they're all really good. But, what really makes Mint special is how all of them are brought together into one, complete whole. As far as I'm concerned, Mint 13 really is the best Linux distribution so far of 2012. Give it a try yourself. 

Download Linux Mint 13 here...


Linux Mint



Linux Mint is a computer operating system based on the Linux distribution Ubuntu. Linux Mint is intended to be a modern, elegant and comfortable operating system which is both powerful and easy to use.  Linux Mint provides a more complete out of the box experience by including proprietary and patented software.
Linux Mint introduced its first release, named "Ada", in 2006. Its latest and 13th release is "Maya".

Linux Mint uses primarily free and open source software, making exceptions for some proprietary software, such as plug-ins and codecs that provide Adobe Flash, Java, MP3, and DVD playback. Linux Mint's inclusion of proprietary software is uncommon; most Linux distributions do not include proprietary software by default, as a common goal for Linux distributions is to adhere to the model of free and open source software.
Linux Mint comes installed with a wide range of software that includes Libre Office, Firefox, Thunderbird, XChat, Pidgin, Transmissionand GIMP. Additional software that is not installed by default can be downloaded using the package manager. Linux Mint allows networking ports to be closed using its firewall, with customized port selection available. The default Linux Mint desktop environments,MATE and Cinnamon, support many languages. Linux Mint can also run many programs designed for Microsoft Windows (such as Microsoft Office), using the Wine software or using virtualization software (such as VMware Workstation or VirtualBox).
Linux Mint is available with a number of desktop environments to choose from, including Cinnamon, MATE, KDE, and Xfce. Other desktop environments can be installed via APT.
Linux Mint actively develops software for its operating system. Most of the development is done in Python and the source code is available on GitHub.
Minimum Size (megabytes): 
783
Maximum Size (megabytes): 
898
Last Stable Version: 
13
Last Release: 
May 23, 2012


Ubuntu 11.10

Linux download

  Ubuntu 11.10 with new changes is released with the code name Oneirk Ocelot. New changes are included in the unity interface of this 11.4 build.

Example: Window controllers on the top side are hidden now.Themes are also updated.Beta version of firefox 7 and Thunderbird 7 are included in the Beta version of Ubuntu.


TV on Linux


A number of cards exist allowing you to watch and record TV on your PC. Most come with software for Windows only, like so many things, but it is possible to do the same thing on Linux. Linux comes with several drivers which make up the Video4Linux drivers. Several cards are supported by these drivers, and a list of them is available at http://roadrunner.swansea.linux.org.uk/v4l.shtml. This is the driver side. You also need software to use the devices.
Several programs are available to watch TV, capture images and even Web applications. A list of some of the
programs is available at http://www.thp.uni-koeln.de/~rjkm/linux/bttv.html including datasheets.

Find hardware information in Linux


When the Linux system boots, it will try to detect the hardware installed in the computer. It will then make a fake file system called procfs and will store important information about your system in it. You can get information about your system simply by browsing the directory /proc. The files in there will contain information such as the processor you have, the amount of memory and the file systems the kernel currently supports. A usefull application exists to browse the /proc file system. It is called Xproc and is available from http://devplanet.fastethernet.net/files.html


Detecting 2 ethernet cards in Linux


To configure an ethernet card in Linux, you need to enable it in the kernel. Then the kernel will detect your ethernet card if it is at a common IO port. But it will stop there, and will never check if you have 2 ethernet cards. The trick is to tell the ethernet driver that there are 2 cards in the system. The following line will tell the kernel that there is an ethernet card at IRQ 10 and IO 0x300, and another one at IRQ 9 and IO 0x340: ether=10,0x300,eth0 ether=9,0x340,eth1 .You can add that line on bootup at the "boot:" prompt, or in the /etc/lilo.conf file. Don't forget to run: lilo
That will reload the lilo.conf file and enable changes.

6 Stages of Linux Boot Process (Startup Sequence)


Press the power button on your system, and after few moments you see the Linux login prompt.
Have you ever wondered what happens behind the scenes from the time you press the power button until the Linux login prompt appears?
The following are the 6 high level stages of a typical Linux boot process.

Auto mounting a partition


It’s been a while. A while since I’ve had to actually had to manually edit the /etc/fstab to automount a partition. So long, that I searched my blog trying to find out how to do it. To my surprise, I’d never actually written one. If I had, I couldn’t find it. Here’s to you, memory:
According to /etc/fstab this is how it’s done
# <file system> <mount point> <type> <options> <dump> <pass>
For those of us that are human, that can mean very little. What you can do, in hopefully slightly more understandable terms is add a line that looks like this:

Ways to install Linux on a netbook


With my new Acer Aspire Netbook, it occured to me that it had been a long time since I’d installed Linux on a system without a CDRom. This post outlines some methods you can use to get it installed
External CDRom install
The easiest method. Plug in the USB CDRom, and install as normal. Perhaps this is a no brainer but to be honest, I forgot about it when I first got my netbook so its worth a mention.
USB Install
If you don’t have an external CDRom drive laying around you can use a USB Stick. The easiest way to get Linux installed via a USB key is too use a handy tool called UNetBootin.
Network install
Network installs are actually easier than people may think thanks to PXE and open source software. Basically you set up a TFTP server, and a DHCP server. The machine wanting to boot gets an IP and downloads the install image from TFTP. There you continue as a normal installation except download the packages from a web server rather than installing from the CD/DVD.

Restrict network access by time or IP address with Squid


There are a number of reasons why you would want to restrict network access. You run a cafe with web access or you have young or teenage children and you want them to only be able to use the network at certain times. Their are certainly tools out there to do this on a PC-by-PC basis, but why not employ a proxy server instead? One of the best (and most robust) proxy servers available for the Linux operating system is theSquid Proxy server. But don’t let the name fool you, you do not have to install Squid on a server. You can just as easily install squid on a Linux desktop machine and control network access from your LAN.
Of course when you open up your /etc/squid/squid.conf file you might be a bit overwhelmed. So in this article I am going to show you two ways to limit access with Squid (instead of tossing the whole configuration file at you at once). I will also show you the quick and dirty method of installing Squid on a Fedora 13 machine. Once done with this article, you will at least be able to control network access by time or by IP address. In later articles we will discuss other ways to control network access with Squid.

Vinagre remote desktop connection for Linux


Do you administer Linux machines? Or do you just need the ability to remotely connect to your Linux machines from other Linux machines? If so, are you looking for an easy solution for this task? There is one, if you are a fan of the GNOME desktop.
Vinagre is a remote desktop tool with plenty of features and ease of use for just about any level of user. It’s enjoying release 2.30.1 so it’s quite mature. In this article I will show you how to install and use the default GNOME remote desktop tool.
Features
Vinagre offers enough features to help make it stand out among other rdp clients: