Good Softwares

Office: Open Office, this is an free alternative to Microsoft Office and can handle MS office formats as well.

CD/DVD Writing: InfraRecorder, this is a free alternative to Nero CD/DVD burner.

PDF Reader: Foxit PDF (Tabbed PDF browsing and Fast), this is not open source however it has a free version as well. Open source Sumatra PDF is good and very fast, however it is still evolving. I was very impressed by the speed and shortcuts similar to Vim.

PDF Printer: PrimoPDF, this is not open source however it has a free version as well. This is best for Windows OS, I have used open source alternative PDF Writer however I am not impressed.

Media Player: Vlc media player, its open source and the best in comparison to proprietary softwares as well.

Image viewer: ACDSee, this is a proprietary software. I tried some open source alternatives and they are no were in comparison to this. It is my personal opinion there might be some good ones that I would have missed.

Compression tools: 7 zip is open source and almost hadles all format zip, rar, tar, .bz2 and .bz etc, the best.

Audio Recording and Editing: Adacity is open source and its very good. This also does conversion to mp3 (additional LAME MP3 encoder dll needs to be copied). If the system powers off / software crash, recovery of the recorded audio is possible. You can look for more info on net.

Editing: Vim - I feel this is the most powerful editor in the world, if you are not familiar with Vim and more used to windows like editor then Notepad++ is another good option.
Unix Emulation for Windows: Cygwin, the best.

Comparison Tool: WinMerge is a good comparison and merge tool. Araxis Merge is a proprietary software and it does much better job than other comparison tools, I prefer this personally.

SCP client: WinSCP, the best.
FTP client: Filezilla
Telnet/SSH client: PuTTY & PuTTY Connection Manager, the best.

Chess: WinBoard with GNU Chess is a good option. If you are a serious player then Fritz (not free) is the best.

Visit: www.osalt.com to check for Open Source Alternative for your proparatory software. Also www.opensourcewindows.org is also a good place to look for Windows open source softwares.

GRUB made easy

GRUB stands for GRand Unified Bootloader, which comes as default Bootloader with most of the GNU/Linux distribution (Red Hat, Ubuntu, Mandriva etc). It is used to boot multiple operating systems installed in the same computer. If you are not familiar with the concept of bootloader, let me just give a brief intro. Once a computer is powered on, its runs some basic hardware test and transfers the control to the selected boot device, mostly it will be your harddisk. However you can configure it to CD-ROM or a USB stick (only if the HW supports), many of us are familiar with this program called BIOS. In fact to modify the boot device we need to change the BIOS settings. Latest hardwares provide a "Boot Menu" hard key as well. Okay coming to the point, Actually the BIOS transfers the control to another program called Bootloader. Now the catch is how does the BIOS know where is the bootloader? Thats simple its always stored in the first 512 bytes in any boot device. The first 512 bytes of a (primary) harddisk is what we call as MBR (Master Boot Record) normally its part of C:\ for Windows users. Guess this is sufficient to get started.

Actually, The complete GRUB bootloader won't fit into 512 bytes, thus 1st part the bootloader (called as stage-1) is stored here, also contains partition table (which tells how the harddisk is split into logical partitions). The stage-2 is actually a text file containing entries which can be modified. This would be our interest here, because just by modifying this file you could boot most of OS (GNU/Linux, Windows, FreeBSD etc) installed in different partitions. Understanding entries in this file is a key in understanding GRUB. Without wasting time let us look into details:

Normally GRUB is stored in the directory: /boot/grub/, this directory contains stage1 and stage2 --> /boot/grub/menu.lst. Below image shows menu.lst file opened in (vim) editor.


An entry to boot windows is similar to this:
title Windows
root (hd0,0)
makeactive
chainloader +1

Let us decipher the commands;
'title' is just a entry to be displayed on the boot-up screen to make a choice.

'root' is an important command which sets the partition in which the OS is present, more often for windows 'rootnovefiy' command will be used instead of root, this is similar to root except it does not mount the partition.

That's fine what is that strange (hd0,0)? This is the GRUB way of naming harddisks, hd - stands for harddisk, hd0 means primary and hd1 means secondary etc. Comma followed by next digit indicates the partition on the disk, thus
(hd0,0) - means primary harddisk 1st partition (Which is normally C:\, If you use windows)
(hd0,1) - means primary harddisk 2nd partition
(hd1,1) - means secondary harddisk 2nd partition
etc, Note that the partition numbering starts from 0 and not 1. Which means (ha0,5) actually means 6th partition, which is sda6. Within GNU/Linux OS partitions are named as either hda or sda based on harddisk type, followed by a partition number. To figure out in your system you can use 'fdisk -l' command with root privileges. Output in my machine was shown below:

[root@localhost sara]# fdisk -l

Device Boot Start End Blocks Id System
/dev/sda1 1 6 48163+ de Dell Utility
/dev/sda2 7 1312 10485760 7 HPFS/NTFS
/dev/sda3 * 1312 PROBLEM 1: 14026 102127616 7 HPFS/NTFS
/dev/sda4 14027 19457 43624507+ f W95 Ext'd (LBA)
/dev/sda5 14027 16708 21543133+ 7 HPFS/NTFS
/dev/sda6 * 16709 19337 21117411 83 Linux
/dev/sda7 19338 19457 963868+ 82 Linux swap / Solaris
[root@localhost sara]#

sda6 and sda7 are GNU/Linux partitions. In this naming convention sdb means secondary harddisk. The naming convention described here is for GNU/Linux, and it varies a bit for FreeBSD. You can use 'fdisk -s' to find it out in FreeBSD.

Okay coming back to the point the third entry in the boot commands,

'makeactive' sets the boot flag of the partitions, which is required for DOS to boot, this flag would be already set however there is no harm in ensuring it.

The last command is interesting,
'chainloader +1', this says chainload the program in the next sector after boot sector. Chainloading in a technique in which the running process will be overlaid by the new process. If the word process itself is new to you then you can assume it somehow loads it. Grub uses this technique to boot windows. This explains all you need to boot windows.

PROBLEM 1:
Say you have installed Windows and GNU/Linux on the same machine and you decided to remove GNU/Linux (as though there is no good reason to this). Assume you deleted GNU/Linux partitions from Windows OS Disk Management and you have restored GNU/Linux partitions for Windows use. Now what happens if you reboot? You will have a surprise with a grub command prompt as shown below
grub>
Your nice GRUB menu would no longer be there. Now How to you boot windows? Obviously you can't boot GNU/Linux as you wiped the harddisk that contained it. Before getting into that, lets understand what has happened? The stage2 of grub is present in /boot/grub/ directory got removed as a part of deleting the GNU/Linux partitions and Grub does not know how to boot your OS now. Or the above mentioned commands are not there for GRUB's reference to boot your Windows OS which is anyway present in the harddisk. So what to do? Grub gives you a nice command prompt from which you can execute commands, if you type 'help' you can see all the commands supported by grub, just by knowing few commands you can do a lot with grub. All the commands that are required to boot windows are already known to you (don't be surprised whatever we discussed in previous section, each of them are commands to GRUB) so just use them,

grub>rootnoverify (hd0,0)
grub>makeactive
grub>chainloader +1
grub>boot

Wow! this will boot your windows without any issue (assuming its installed on C:\). So nice of GRUB, it doesn't let you down even when GNU/Linux was completely removed. The last command 'boot' is new, which means boot the OS with the specified configuration.

PROBLEM 2:
Okay coming to your next question, I don't want to do this (above procedure) every time I boot windows how can I get it back the same way it was before installing GNU/Linux?
Before answering this let us understand why do you get a grub command prompt every time you boot. This is because you would have installed GRUB in MBR and stage1 of GRUB is present there. Now the actual question boils down to how do I remove grub from MBR? this can't be done by GRUB itself. Thus you need a windows utility to do this. This is called 'fdisk', this comes as a part of Windows boot disk or CD. During our college days we use to use a 5.14" floppy for boot disk, I guess they are no more in existence now. Once you manage to get a boot CD containing FDISK program rest is simple, FDISK has a hidden option /MBR which recovers the MBR, Thus executing the below command would fix the MBR.

/>FDISK /MBR

This will re-write MBR thus there will be no traces of GRUB being present there. Thus you will get back your Windows as it was before.


Enough of windows, now Lets turn our attention to GNU/Linux. An entry to boot GNU/Linux is similar to this:

title Linux
root (hd0,5)
kernel /boot/vmlinuz root=/dev/sda6
initrd (hd0,5)/boot/initrd.img

As explained before 'title' and 'root' commands are the same. The new commands are 'kernel' and 'initrd'. Kernel command gives the Linux kernel to boot and the following are the options to kernel such as root=/dev/sda6. What does this /dev/sda6 mean? This basically gives the location of the program /sbin/init which the father of all Linux process and gets started by the kernel once its up. In your particular grub file this line might look little complex than this, however the essence is same, you might have a option to show a splash image etc.
'initrd' command is used to specify the path of the RAM disk image to start with. Actually vmlinuz and initrd.img are symbolic links to the version of the kernel used and initrd image used. The below output confirms the same.

[root@localhost boot]# ls -l
...
lrwxrwxrwx 1 root root 33 2009-02-17 06:58 vmlinuz -> vmlinuz-2.6.27.10-desktop586-1mnb
lrwxrwxrwx 1 root root 36 2009-02-17 06:59 initrd.img -> initrd-2.6.27.10-desktop586-1mnb.img
...

The Linux kernel version used in my machine is 2.6.27.10 as indicated above. Okay why a symbolic link why not the direct kernel name? Yes the kernel name can directly also be used, however this method has an advantage. Say I have updated my kernel version to a latest version, then just the symbolic link of kernel and initrd needs to be changed and no the entry in the grub. Even changing the symbolic link also will be automatically taken care for you when you update or in some distribution it makes a new entry with the new kernel version in the boot-up menu.

PROBLEM 3:
Say you have installed GNU/Linux successfully and you have just got the grub prompt not the Menu, how to boot GNU/Linux now? This might not be the case mostly however its nice way to learn GRUB, you can simulate this by typing 'c' when the grub menu is displayed. This will take you to grub command prompt.
Here we go.
Now the first question is how do I
know in which partition GNU/Linux is installed? Its easy to find out this using 'find' command
grub>find /sbib/init
(hd0,5)
grub>
This indicates that GNU/Linux is installed in (hd0,5) which sda6 of the harddisk. Now we can set the root to this partition
grub>root (hd0,5)

To set the kernel,
grub>root /boot/vmlinuz[Press TAB Key]
vmlinuz-2.6.27-desktop586-0.rc8.2mnb vmlinuz-2.6.27-0.rc8.3.1mdvcustom vmlinuz-2.6.27.10-desktop586-1mnb
[Tab key] auto-completion is a easy way to find out existing files.

Even Tab key works after
grub>root ([Press TAB key]
which displays all the possible partitions in the harddisk. These are some cool features of GRUB.

Okay we will set the kernel as vmlinuz-2.6.27.10-desktop586-1mnb,
grub>root /boot/vmlinuz-2.6.27.10-desktop586-1mnb
the above command can also be written as
grub>root (hd0,5)/boot/vmlinuz-2.6.27.10-desktop586-1mnb
in this case 'root' command is optional as we are specifying the absolute path using (hd0,5).

Similarly initrd image,
grub>root /boot/initrd[Press TAB Key]
initrd-2.6.27-0.rc8.3.1mdvcustom.img initrd-2.6.27.10-desktop586-1mnb.img initrd-2.6.27-desktop586-0.rc8.2mnb.img
Set it same as kernel version, thus initrd-2.6.27.10-desktop586-1mnb.img
grub>root (hd0,5)/boot/initrd-2.6.27.10-desktop586-1mnb.img
IMPORTANT NOTE: Here (hd0,5) is not optional, this should always to absolute path.

All set, now 'boot' command will boot GNU/Linux successfully
grub>boot
If you get something like "Kernel Panic", It might be because you have missed the initrd command.

Cool Now you are equipped with knowledge to boot different OS from GRUB prompt as well as modify stage2 of grub, menu.lst file. Try them!

There are some more interesting commands like:
save - to save the previous boot option, save default is needed in the begging to use this
hide - to hide a partition, this is there to overcome the drawback of DOS/Windows bootloader
unhide - Reverse of hide
map - to map a secondary harddisk as primary, this is there to overcome the drawback of DOS/Windows bootloader

I will leave it you to explore them. I hope this article would have made Grub easy for you to understand. If you have any queries or feedback you are most welcome.

How to fix a corrupted MBR is another interesting thing, that would require another article. Hope I will write it sometime later.

VMware Virual Mechine

Can I install Linux inside windows? Yes. Its possible using the virtualization technology. VMvare virtual machine allows you to do that. I installed Ubuntu inside windows using Ubuntu 8.10 Live CD .iso file. It worked fine. This is a cool way to install as you don't need  a CD as well. Of course it can be installed from CD also.


Its not just for Windows OS it can work with other OS as well, for example you can install Windows inside Linux, or Windows inside Mac, or Windows inside Windows :-) etc. VMware takes care of all the abstraction needed for the OS through its virtualization technology. In fact you will get a different IP address for the new virual OS and you can ping the host OS and vice a versa.

How is it possible? might be a question which comes to our mind. Actually the same processor is shared for both OS, If you have a dual core then single processor would be used for virtual OS. RAM is also shared which means enough RAM should be there, I had 1GB RAM and the installer automatically chose 512MB. Its obvious that minimum harware requirements needed by the both OS needs to be met, after sharing harware resources as well. You can run many virtual OS simultaneously if you have sufficient hardware resources.

What about harddisk? In fact harddisk is abstacted as a file of 8GB or more than that as per choice. This file can be split in 2GB sizes by selecting an option during installation. It is pariculary useful because 2GB size can easily fit into removable media like USB stick and can be traferred from one machine to other. The hardisk file format is called .vmdk (Virtual Machine DisK format) for more infor refer: VMDK. The main virtulal machine file is called as .vmx. All these files will be present in the installation folder, in my case it was C:\My Virtual Machines\Ubuntu_8.10\. Once you have this complete folder copied I guess you can even open it from another mechine using VMware Player.


VMware player is free software from VMware and it can be used to open a virtual mechine file system (.vmx). As the name indicates its just a player and you can't create virtual mechine (.vmx and .vmdk files) using VMPlayer.

So now the catch is how do we create a virtual machine? This can be done by VMware Work station, which is licenced. I used a trial vesion to crate a new virtual mechine. However there are may virual machine dump available in the internet which can be direcly used with VMware Player. I guess there some associated procedures to adapt it to a particular harware. I didn't try this so I wont be able expain more on this. One issue I faced during the installtion was that when using direct install CD .iso files, after few initial installation steps it was checking the real CD rom drive and reported "Media not Present" error. However using Live CD .iso file solved the issue. I guess you will not face any such issues if you use CD directly.

Personally it was exiting for me when I tried this. Hope you will also find it in the same way. Try it out, All the best!

Mandriva Linux Experience

My sister received a Mandriva 2008 Spring DVD as a part of a Linux workshop she had attended. She had some problem in her computer, So I suggested her to try the New Mandriva DVD. She could successfully install it , though she had no prior experience of installing Linux. Needless to say the installation procedure was user friendly.


I had never used Mandriva Linux, thus I was curious to see when I get back to home from Bangalore. When I saw that it was Wow! experience. The user interface was equivalent to Vista in terms of look & feel. From functionality wise it had more features than Vista. Most of the Linux disto (means a Linux distribution) I had used, had GNOME as the default Desktop. Where as Mandriva's default is KDE (it supports GNOME as well). Okay if you are new to Linux KDE and GNOME are two different Desktop Environment for Linux. KDE is graphical and heavy, whereas GNOME is simple and light.

The panel feature of KDE was really wonderful, you must try it. It allows you to have a very flexible desktop with all you need, its similar to Gadgets in Vista however much versatile than that. I was really impressed by the look & feel. "Oxygen" Theme and "Land of Peace" wallpaper combination was very pleasant.


One thing I didn't like was there was no straight forward way to access file system, Of course Dolphin file manager was present, However it was difficult to locate it through the Menu. Its in System → Tools → More → Dolpin File Manager. Once you are used to you can make a panel link on your desktop for Dolphin file Manager.


Another interesting thing is that, this distro tries to provide the maximum interoperability with windows, i.e you can import windows fonts seamlessly in Mandriva. From "Control Panel" -> "Install windows fonts". It automatically searches windows drives, installs all the fonts. Another good thing is that, all your windows drives get default mounted here, which is convenient for people who are new to Linux, of course this happens in Ubuntu as well however you will be required to enter the password to complete the operation. And there is a way to import your windows documents as well from Mandriva Control Panel.

One advantage is that the DVD contains almost all the required packages, thus even if you don't have internet connection you can install many of the packages. I could install KDevelep (C/C++ Development IDE)and VLC player successfully from the DVD. The best part is codec's are part of the default installation which means you can play most of the popular audio/video formats without any issues.

I was so impressed by the KDE and the Konsole ( Shell in KDE), I decided to install Mandriva in my Laptop ( DELL Inspiron 6400). Installed Mandriva One 2009 on my Laptop and it was working fine. Overall in my opinion this is a good Linux Distro with appealing GUI. Looks like a real competition to Windows in terms of look & feel. In fact it supports 3D desktop, I didn't experiment it, may be you can try it if you have a high end hardware. Hope you will like it. Give it a try and you won't regret it.

Ubuntu (post) install issues 7.10

I had no issues with Ubuntu installation procedure as such, in fact it was very easy to install. I am not going to describe how to install Ubuntu on your computer, in fact you can refer to Ubuntu website for that. Here I am trying to present some post installation issues, which were blocking me to use it as a full fledged Desktop for all my needs.

I had used Red Hat Linux during my college days and I enjoy using the powerful shell that Unix/Linux provides. My friend told me that Ubuntu works fine on Laptops. So I decided to try it out on mine (DELL Inspiron 6400 Laptop with Vista pre-installed). Downloaded Ubuntu 7.10 from Ubuntu website, and installed it.

BIT OF INFORMATION:
By default Ubuntu does not give you a root account. Instead use "sudo" before any command to run it as root/admin. Thus to edit /etc/X11/xorg.conf
vim /etc/X11/xorg.conf → Will not work, as its a privileged file and a normal user can't save changes to it.
sudo vim /etc/X11/xorg.conf → Works; it might prompt for a password. Just enter user (created during installation) pwd.

Boot-up issue:
The first issue I had after successful installation is that I could not see the GUI, I could only login in cmd mode. After a bit of search in the Internet came to know that for a DELL Laptop's we might need to modify the X11 configuration i.e /etc/X11/xorg.conf needs to be modified. Did the below modifications,

Login in (recovery) mode and add the below last 3 lines in file /etc/X11/xorg.conf
Section "Monitor"
Identifier "Generic Monitor"
HorizSync 36-52
VertRefresh 36-60
Option "MonitorLayout" "LVDS, AUTO"

in the next boot showed a nice brown GNOME desktop. I was very happy to see a Linux Desktop on my Laptop.

Connecting to internet:
Connecting to internet was seamless, just plug-in the broadband cable and rest is automatic, you are connected to net. This is case only if you have DHCP kind of configuration with ISP. Airtel Broadband works fine.

Multimedia play:
One these display issue was sorted out, I just tried playing a .mp3 files, however it said codec missing and prompted for download when you say "YES", the rest is done. This is the same for any preparatory audio/video formats. I guess these codecs are not supplied in the default installer as they are preparatory or due to license issues. However this is not a problem really if you have internet. Otherwise sad thing is you wont be able to listen music unless they are open formats like .ogg etc. Anyway I installed my favorite media player "vlc", which supports most of the formats without any codec dependency. I use the same in Windows, thats the reason I installed this. The default media player - “Totem Player” works fine and there are no issues.

C-Compiler (gcc) issue:
Basically I am a C programmer so I was curious to check whether C compilation works fine or not. Started writing a "Hello world" program to check the compilation. To my surprise it was not compiling. gcc and make were there, however necessary stdlib header files and libraries were missing. Once you are connected to internet, installing any package is trivial. We can either use "Synaptic Package Manager" or the cmd line "apt-get install ". Both are really good. Making C program compile is essay, just install “build-essential” package either from "Synaptic Package Manager" or cmd line as,

sudo apt-get install build-essential

Luckily this package comes with a installation CD, thus even if you don't have a internet connection you would still be able to install this, Which is very good thing. To install C manual and full fledged Vim editor you need internet connection and below are the commands

sudo apt-get install manpages-dev glibc-doc → for man pages
sudo apt-get install libncurses5-dev → for ncurses.h

TIP: Can also use System | Administration | Synaptic Package Manager to install any package trough GUI.

sudo apt-get install vim-runtime
sudo apt-get install vim-full
sudo apt-get install gvim

Above command gets you all capabilities of favorite VIM editor.

Automatic update works very well in Ubuntu. In fact I updated to 8.10 from 7.10 through net. It was a two step process 7.10 → 8.04 (LTS) → 8.10. I would better recommend installing Latest version directly as it takes lot of time for updates. One nice thing is that 8.10 had Brasso, a nice CD burning tool. Earlier version had something like ISO write, which also worked well.

The best part is it even prompted for installing ATI Radeon drivers automatically, which helped in getting all the Power related options working like Hibernate. This was not the case in Mandriva even when I updated over the internet. Still Hibernate doesn't seems to work :-(

Ubuntu is a very simple to use and elegant Linux distro I enjoyed using it. I strongly recommend it. As a personal observation, it was very stable in my Laptop compared to Mandriva, however Mandriva was giving a best look & feel and simpler user interfaces similar to Windows. The choice depends on your taste and requirements.

Books to Read

Its always a good idea to read the books that matches your wavelength. I mean you should start with books that are intended for your level. Even if a book is very good check whether it matches your level before reading it. Now you may be asking me, "How do I find out that?". Its simple, if you are able to understand and appreciate the concepts explained in the book then we can say its at your level. Here I have listed some of the very good books that I have come across. Hope this will help you picking a right book for your level. The books are arranged in a order so that normally fist book would be to start with and can proceeded to other books to gain more depth and not too many entries are there which might interest you.

C:
1.Let Us C (Fifth Edition) - Yashavant P. Kanetkar
A good book to get started with, especially useful for college students. PDF version is available in the net, however its better to read the book version as this might be your first book. Available in PDF format in net.
2.The C programming Language – Brian W.Kernughan, Dennies M. Ritche
Also called as K&R book, written by author of C Language, this is like a bible for C. Better to have a hard copy for reference, recommended only after learning C from a basic book like the above one. Not a good idea to start with this book as every line contains lot of compressed information about the language. Available in PDF format in net.
3.Expert C Programming: Deep C Secrets - Peter van der Linden
Written by a Compiler writer at Sun Miscrosystems, a must for all professional C programmers. As the name suggests Deep C secrets are unrevealed, this book is written in a casual tone which encourages reading, even has some fun for you at the end of every chapter. Last chapter on C++ is a very good introduction to C++. Available in PDF format in net.
4.Linked Lists and Binary Trees – Stanford University tutorials
These are very useful compared to any book. Better to read them again and again before attending interviews in C. Available in PDF format and You can download it from Stanford university website.
Pointers and Memory
Linked List Problems
Binary Trees
5.C Programming FAQs: Frequently Asked Questions– Steve Summit
Answers to most commonly confused language constructs. Online version and hard copy is available. Good to read them once if you are facing a interview in C. Its called as comp.lang.c.
C FAQ

C++:
1.Let Us C++ - Yashavant P. Kanetkar
This is a good book to get started with If you like Let us C, then you can start with this for C++. Concepts are presented with simple examples (which might not be useful in programming problems) so that the concepts are well understood. Once you grasp the basics from this books, Its better to read another book which would present typical real world examples. The one below is very useful in that regard.
2.C++ Annotations - Frank B. Brokken
Online version is available, Concepts are presented very well I recommend this book.
C++ Annotations
You can get a PDF version as well.
3. Thinking in C++ - Bruce Eckel
This book is for a thirsty person who wants to know answers to why questions.If you are C programmer migrating to C++, then this book is for you. One of the best books interns of treatment of the subject. OOP concepts are explained very well in the first chapter and what a linker does is also demystified. PDF version can be downloaded from net:
Thinking in C++ download
Thinking in C: Foundations for Java & C++ - Chuck Allison
Its a flash-based audio-visual seminar which comes in CD with Thinking in C++ hardcopy or can be downloaded from Thinking in C download.
Is a very good seminar intro to C, its worth watching.
4.The C++ Programming Language - Bjarne Stroustrup
Written by author of C++ Language, its a nice reference. First chapter gives a very good overview of what C++ can do for you. If you are not able to understand this book better revisit after reading some other book suggested above.

Perl:
1.Essential Perl
This is not a book, this is a short tutorial to Perl. Perl is a kind of Language which you learn in few hours and start writing programs provided you are already familiar with a programming language like C. This tutorial serves that purpose. Just as 25 page PDF file, after which I am sure you will be able to write your first program for ant text processing task. You can download it from Stanford university website.
Essential Perl
2.Learning Perl - Randal Schwartz, Tom Christiansen & Larry Wall
Called as Lama book. Very good book for the Beginners. I recommend this book, concepts and Language are presented very well. Available in PDF format in net.
3. Mastering Regular Expressions - Jeffrey E. F. Friedl
Core logic of every perl program will be a regular expression (regex), mastering regex would help in so many ways, while you use a grep command or seacrh / replace a text in vim etc. Though regex can be treated as a language of its own, its normally associated with other languages, however only the syntax varies the core logic remains same. Languages like Perl, Java, .NET etc support regex. This is a vary good book, I don't think there is a better book for regex, reading this would make you life easy for so many problems otherwise you would have struggled. Available in PDF format in net (only 1st edition), better to have a hard copy of a Latest edition. Its a must to read.
4.Programming Perl - Larry Wall
Called as Camel book. This is an ultimate reference written by the author, not page by page reading required. You can refer this when needed. However initial chapters explains the design philosophy of perl which are good to know. Available in PDF format in net.

Unix:
1.The Unix Programming Environment - Brian W. Kernighan and Rob Pike
This is a very good book to learn Unix / Linux Sell. I recommend this book, the way things are presented in this book and systematic and easy to learn.

GSM:
1.The GSM System for Mobile Communications - M. Mouly and M. Pautet
For people who work on Mobile Side, this is a very good book to learn the Technology before dwelling into standards. Concepts are presented by answering Why they are needed?
2.GSM Networks: Protocols, Terminology, and Implementation - Gunnar Heine
I haven't read it completely. However I feel this book presents the network side concepts well. Its is good book for people working on the Network Side.

ARM:
1.ARM system-on-chip architecture – Steve furber
Very good book for knowing ARM from scratch. I was not from CSE background, still I was able to understand the concepts presented. Must for people who work in an embedded environment using ARM processor.

VIM:
A tutorial that comes with VIM is the best thing to get started with once you are used to it. May be you can read the PDF version of the book available in vim.org website: The Vim book by Steve Oualline.