Collection of Free ebooks on Linux and Unix. Check out the books and I am sure you will find lot of valuable books for your work or study.

• Linux kernel in a nutshell
• Linux Admins Security Guide
• Linux Security How to:
• Linux Firewall Configuration, Packet Filtering & netfilter/iptables:
• Linux Device Drivers, Third Edition
• Linux System Administrator's Guide, Lars Wirzenius, Joanna Oja, Stephen Stafford, Alex Weeks
• Linux Client Migration Cookbook
• Linux Command Line
• The Linux Starter Pack 
• The Art of Unix Programming
• The Linux Development Platform
• Understanding the Linux Virtual Memory Manager 
• Linux Internals
• Linux Gamers - HowTo
• Linux Device Drivers, 2nd Edition
• The Linux Cookbook, Great book by Michael Stutz 
• Linux-For-Dummies 8th edition, Dee-Ann LeBlanc, Richard Blum
• Linux Administration Made Easy (LAME), Steve Frampton
• The Big Online Book of Linux Ada Programming, Ken O. Burtch
• GNU Bash Reference Manual –
• Knowing Knoppix –
• Vi iMproved (VIM) –
• GNU Emacs manual
• Java Application development on Linux
• Writing GNOME Applications
• KDE 2.0 Development
• GTK+/Gnome Application Development
• Secure Programming for Linux and Unix
• Self service linux – Mastering the art of problem determination
• Producing Open Source Software
• Ubuntu Pocket Guide and Reference
• Java Application Development On Linux
• GNU Autoconf, Automake and Libtool - free book on popular GNU tools
• The Unix Shell Guide ©1996 (Norman J. Buchanan, Douglas M. Gingrich)
• Sed - An Introduction and Tutorial ©2012 (Bruce Barnett)
• C-shell Cookbook ©2006 (Malcolm J. Currie)
• Programming the Unix/Linux Shell (Claude Cantin)
• Gawk: Effective AWK Programming ©2009-2011 (Arnold D. Robbins) 365 pages
• Easy Shell Scripting (Blessen Cherian)
• Writing Shell Scripts ©2000-2006 (William Shotts, Jr.)
• The Unix-Haters Handbook ©1994 (Daniel Weise, et al) 329 pages
• Linux: Rute User's Tutorial and Exposition The Book of Webmin

Below is some random collection of books, tutorials, free resources and materials on UNIX and LINUX

http://itdiscover.com/links/free_it_materials/operating_systems

Linux and Unix

1. Linux-Network Admin Books ( 702 ) 
   This web site is designed to act as a central source of Linux information and as a voice for the promotion and advocacy of the Linux operating system. The main goal is to inform the public about every company, project and group that uses the Linux operating system and to report on the hard work of countless developers, programmers and individuals who strive everyday to improve on the Linux offerings in the marketplace.


2. The Linux Portal ( 1784 ) 
   One of the cornerstones of a computing portal site is to present users with a list of all the available software. LinuxLinks has the largest compilation of Linux links available. We're currently approaching 30,000 links that point you to all of the essential Linux software, the vast majority of which aren't included in a standard Linux distribution. We also recognise that Linux users aren't solely interested in software that runs 'natively' on their platform. Accordingly, we have separate categories for Java and Web based software, which run seamlessly in Linux. We also cater to Mac OS X users as well.


3. Free Books on Linux, Java, Python, Perl, Networking, HTML, Web Dev ( 873 ) 
   It is an index of /pub/document/book where all the details of Linux, Java, Python, Perl, Networking, HTML, Web Development can be got.


4. Linux Course and Resources Web Site ( 427 ) 
   This website is dedicated to provide you with information and reference material related to the Linux course being conducted at Sir Syed University of Engineering & Technology.


5. Free Books from Other Publishers ( 463 ) 
   The GNU Project was launched in 1984 to develop a complete UNIX-like operating system which is free software.


6. Securing and Optimizing Linux ( 426 ) 
   Securing and Optimizing Linux is a RedHat Edition. It deals with the hardware and software part of Linux system.


7. Linux Bible ( 511 ) 
   This book is the map and guidebook to the world of Linux.


8. Web Programming Desktop Reference ( 436 ) 
   In this ebook every effort has been made to build the most comprehensive and up-to-date reference of the HyperText Markup Language in encyclopedic format.


9. Learning Linux Reference Materials ( 522 ) 
   These books provides essential references for the growing number of LINUXr users.


10. SCT Online Books ( 465 ) 
    Following books are available linux (.pdf) linux-sistem-yonetimi (.pdf) Network_Scanning_Techniques (.pdf) Securing-Optimizing-Linux-RH-Edition-1_3 (.pdf) bash High-Performance_Networking_Unleashed Linux_System_Administrators_Survival_Guide LinuxSystemAdministratorsSurvivalGuide Maximum_Security Red Hat Linux Unleashed - more graphics Red_Hat_Linux_Unleashed UNIX Unleashed - Internet Edition - SAMS UNIX Unleashed - System Administrators Edition - SAMS Unix_Unleashed Unix_Unleashed_Internet_Edition Unix_Unleashed_System_Administrators_Edition UnixUnleashedvisitors.


11. E-books :: Unix, Linux & X-Windows ( 480 ) 
    This site gives us links to various ebooks on Unix, Linux & X-Windows.


12. Larch/C++ Reference Manual ( 519 ) 
    Larch/C++ is a notation for formally specifying the behavior and interfaces of C++ classes and functions. The goal of this reference manual is to precisely record the design of Larch/C++.


13. Red Hat Linux Manuals ( 491 ) 
    Red Hat Enterprise Linux is the premier operatng system solution for open source computing.


14. Linux Kernel 2.4 Internals ( 518 ) 
    This documentation is free software.This book was written for the purpose of supporting the short training course/lectures that was given by the Author on this subject.


15. GNU Manuals Online ( 580 ) 
    The GNU Project was launched in 1984 to develop a complete UNIX-like operating system which is free software.


16. Secure Programming for Linux and Unix HOWTO ( 842 ) 
    This book provides a set of design and implementation guidelines for writing secure programs for Linux and Unix systems.


17. Linux Client Migration Cookbook - Version 2Part 1 Choosing Linux ( 843 ) 
    Part 1 Choosing Linux Chapter 1. Introduction Chapter 2. The case for migration Part 2 Planning the pilot migration Chapter 3. Organizational and human factors planning Chapter 4. Technical planning Chapter 5. Linux architecture & technical differences Part 3 Performing the pilot migration Chapter 6. Migration best practices Chapter 7. Client deployment models Chapter 8. Client migration scenario Chapter 9. Integration how-tos Part 4 Appendixes Appendix A. Linux glossary for Windows users Appendix B. Using enterprise management tools Appendix C. Automating desktop migration - Versora Progression Desktop Appendix D. Multi-station computing deep dive - Using Userful Desktop Multiplier Appendix E. Client personalization Appendix F. Desktop automation and scripting Appendix G. Application porting


18. Linux Fundamentals Course ( 924 ) 
    This course includes the history of Linux and what distinguishes Open Source Software from proprietary software. On the practical side students learn the fundamental commands and approach needed to start using Linux.


19. Free Linux Internals Course ( 971 ) 
    This course is designed to help the student understand the inner workings of the Linux kernel.


20. Free Shell Scripting Course ( 1095 ) 
    This course teaches students how to create shell scripts, the use of Regular expressions, file manipulation with sed, grep and awk and how to tie all this new knowledge into scripts that make using Linux so simple.


21. Free Linux Electives Course ( 917 ) 
    This course teaches students how to configure server serivices such as the Apache web server, the Squid Proxy server, the Bind name server ,Sendmail and Exim Mail servers are discussed.


22. Unix Tutorial ( 864 ) 
    A self-study workshop to review and/or learn a wide range of Unix tools, including shell scripts, awk, lex, yacc, grep etc.


23. Linux Home Networking ( 1158 ) 
    This site covers topics needed for Linux software certification exams, such as the RHCE, and many computer training courses.


24. Linux Documentation ( 924 ) 
    Linux HOWTOs are documents which describe in detaila certain aspect of configuring or using Linux.


25. Linux Study Guide ( 1067 ) 
    Linux Study Guide contains : Editor's Letter Overview of Linux Certification Programs Preparing for the RHCE Exam How to Study for the Linux Exams An Overview of Vendor-Neutral Linux Study Guides Test Your Knowledge of Linux Administration


26. CertCities.com - Linux/Unix News ( 1136 ) 
    CertCities.com Linux/Unix News an online magazine for the certified IT professional community. on what is happening in the Linux/Unix  field


27. Tutorialstuff ( 1490 ) 
    Tutorialstuff.com for all the latest tutorials in Operating Systems, Programming, Software,Browser,etc.


28. Linux Network Admin Guide ( 956 ) 
    Free online Linux network administrator guide


29. Ubuntu Linux Essentials - Free book ( 981 ) 
    Free Online book on Ubuntu Linux Essentials


30. Free books - Fedora, VB, Ubuntu Essentials ( 976 ) 
    Techotopia is a library of free on-line IT books covering a wide range of topics including operating systems, programming, scripting, system administration, databases, networking and much more.


31. Boot and run Linux from a USB flash memory stick - Pen Drive Linux ( 1166 ) 
    Carry a portable Linux version with you on a USB flash pen drive. Bring your portable desktop with you wherever you go. USB Linux installation enables you to install a portable Linux operating system on a flash drive or USB key no larger than your thumb


32. Free Linux eBooks ( 923 ) 
    A large collection of eBooks teaching users everything from the basics to advanced linux.


33. HowtoForge provides user-friendly Linux tutorials about almost every topic. ( 1596 ) 
    

    HowtoForge provides user-friendly Linux tutorials about almost every topic.

    Howtos

    •     Linux
      • Android
      • CentOS
      • Debian
      • Fedora
      • Kernel
      • Mandriva
      • PCLinuxOS
      • SuSE
      • Ubuntu
    •     Web Server
      • Apache
      • Cherokee
      • Lighttpd
      • nginx
    • Backup
    •     Control Panels
      • ISPConfig
    •     DNS
      • BIND
      • MyDNS
      • PowerDNS
      • djbdns
    • Desktop
    •     Email
      • Anti-Spam/Virus
      • Postfix
    • FTP
    • High-Availability
    • Monitoring
    • MySQL
    •     Programming
      • C/C++
      • PHP
    • Samba
    •     Security
      • Anti-Spam/Virus
    • Storage
    •     Virtualization
      • KVM
      • OpenVZ
      • VMware
      • VirtualBox
      • Xen
    • Other
    • FreeBSD
    • Commercial


34. Ubuntu Unleashed - Tweaks, Tricks, Tips and more. ( 1291 ) 
    Ubuntu unleashed is a great site for Ubuntu users. It has Ubunutu Tweaks, Themes, Apps, CLI, Tricks, Hacking, Cracking and Customization . A good collection of articles on above topics.


35. 10 must-have Linux cheat-sheets ( 1165 ) 
    1.Linux Command Line Tips 2.Unix/Linux Reference Card 3.One Page LInux Manual 4.Linux Security Quick Reference 5.Screen VT100/ANSI Terminal Emulator Cheat Sheet 6.Vi/VIM Graphical Cheat-Sheet 7.Firefox Keyboard and Mouse Shortcuts 8.Gimp Reference Card 9.Debian Reference Card 10.Google Cheat Sheet