Advanced Bash Scripting
http://www.tldp.org/LDP/abs/html/

Advanced Linux Programming
http://www.advancedlinuxprogramming.com/alp-folder

autoconf, automake and libtool book
http://sourceware.org/autobook/

awk Tutorial
http://www.vectorsite.net/tsawk_1.html

Bash Programming Introduction
http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html

Bash Quick Reference
http://www.ss64.com/bash/

Beginning LaTeX
http://www.cs.cornell.edu/Info/Misc/LaTeX-Tutorial/LaTeX-Home.html

Beginner's Resources to Learn Programming Languages
https://blog.vodien.com/beginners-resources-to-learn-programming-languages/

Beej's Guide to Network Programming
http://beej.us/guide/net/

Building packets
http://packetstormsecurity.nl/cisco/cisco.c

C++ tutorial for C programmers
http://www.4p8.com/eric.brasseur/cppcen.html

Device Driver example
http://www.cs.wpi.edu/~claypool/courses/3013-A03/projects/proj3/

GTK Tutorial
http://www.gtk.org/tutorial/

Java Really Big Index
http://java.sun.com/docs/books/tutorial/reallybigindex.html

LaTeX Quick Reference
http://computing.ee.ethz.ch/.soft/latex/green/ltx-2.html

lex and yacc tutorial
http://www.tldp.org/HOWTO/Lex-YACC-HOWTO.html

libpcap Tutorial
http://www.cet.nau.edu/~mc8/Socket/Tutorials/section1.html

Linux Device Drivers (2.4 kernels)
http://www.xml.com/ldd/chapter/book/

Linux Device Drivers (2.6 kernels)
http://lwn.net/Kernel/LDD3/

Linux Game Development
http://lgdc.sunsite.dk/

Linux Kernel Module Programming Howto: 2.4 kernels
http://www.tldp.org/LDP/lkmpg/2.4/html/

Linux Kernel Module Programming Howto: 2.6 kernels
http://www.tldp.org/LDP/lkmpg/2.6/html/index.html

Make GNU
http://www.gnu.org/software/make/manual/

MPI Tutorials
http://www.mcs.anl.gov/research/projects/mpi/tutorial/

POSIX Threads Programming
http://www.llnl.gov/computing/tutorials/pthreads/

Programming in C - Brian W. Kernighan Tutorial
http://www.lysator.liu.se/c/bwk-tutor.html

Programming Tutorials - Hari
http://www.geocities.com/kollurihari/hari/programming.html

Programming with pcap
http://www.tcpdump.org/pcap.htm
http://www.cet.nau.edu/~mc8/Socket/Tutorials/section1.html

Qt Designer and KDevelop
http://women.kde.org/articles/tutorials/kdevelop3/

Qt Designer Tutorial
http://doc.trolltech.com/3.2/designer-manual.html

Serial Drivers
http://www.linux.it/kerneldocs/serial/serial.html

Serial Programming Howto
http://www.tldp.org/HOWTO/Serial-Programming-HOWTO/index.html

Shell Scripting Tutorial
http://freeos.com/guides/lsst/

Simple DirectMedia Layer
http://www.libsdl.org/index.php

Unix Programming FAQ
http://www.faqs.org/faqs/unix-faq/programmer/faq/

Wataru Nishida's System Programming Documentation Site
http://www.skyfree.org/