Computer Language

Here is a list of resources that I found useful in studying different computer languages:

Objective C

Learn Objective-C

GCC:

An introduction to GNU attributes
An Introduction to GCC for the GNU Compilers gcc and g++ good explanation on compilation options and etc
GCov for code coverage
Valgrind for memory check
G Profile
Automake
A list of discussions on static compilation:

Make:

Make Menual
Recursive Make Considered Harmful A paper on recursive Make and suggestions on compiling multil-directory source files

XMLRPC

XMLRPC provides quick and flexible implementation for web services.

Perl:

Essential Perl A quick introduction to Perl. Very good for beginners.

Python:

Python Tutorial
Networking in Python (a tutorial slide)
Library Reference Very concise description (e.g. in regular expression

Awk:

An Awk Tutorial Quick overview and clear syntax.

Shell scripts:

Steve's Bourne / Bash shell scripting tutorial I think this book is more careful in terms of the usage of different names and etc. Should follow them to avoid lots of small mistakes
Linux Shell Scripting Tutorial -- A Beginner's handbook I like this book. It covers topics that are most useful in shell. An other location for this book.
Shell Script Programming A short discription on BASH programming -- in one page, which means it is easy to search.
Linux Programming A simple tutorial for programming in Linux: including shell, c/c++ and X

GNU Plot:

GNUPLOT 4.0 - A Brief Manual and Tutorial A quick tutorial for beginner.
Introduction to GnuPlot More details on parameters such as line sytle and etc.
Master Manual

SQL:

SQL Tutorial If you are looking for syntax of SQL... very easy to navigate and find your answer.
MySQL reference manual For lookup. From installation, account management to sql syntax and performance. very detailed.

PHP:

3 Days to learn PHP/MySQL (in Chinese) Very simple tutorial for beginners to learn how to install and program php with mysql. Be careful that some of the commands are out-dated or non-recommended and you'd better to use it with MySQL reference manual and PHP manual if you want to master the techniques accurately.
PHP manual For lookup. again, every details.
how to write a php extension I think it is a talk for beginners.

Apache:

Apache API C++ cookbook

Apache API C

JavaScript:

David Crockford's website. Lots of good stuffs about Javascript:
- Prototypal inheritance>
- Classical inheritance
- about the scope of the objects (variable, functions and etc) good explanation.
- JSon
JavaScript Learning Center Kind of tutorials

HTML:

HTML Tutorial

ClearSilver

Tcl/Tk:

Tcl/Tk information by Team Niehaus There is a simple tutorial which is good for beginners. Also, there is an online book (Tcl and the Tk Toolkit by John Ousterhout). They also have links to other resources.

OTCL:

Information from Berkeley Continuous Media Toolkit Project A simple tutorial for OTCL. API descriptions. Good examples.

GDB:

GDB tutorial. Very simple one-page tutorial of GDB.

GProfile:

GProfile Tutorial Very simple one-page tutorial of GProf.

Latex:

The Not-So-Short introduction to Latex "Latex in 139 minutes". I like it as a handbook for Latex.
Latex Wiki

NS2:

NS by Example short and simple tutorial for beginners.
NS Manual The thick book with all details. Make sure to check all the parameters with it before you run a new ns simulations.
A NS-2 Tutorial There are some good examples for data recording (using monitor instead of trace)

Sendmail:

a concise tutorial for simple mail service configuration, from very beginning concepts

Thread programming:

RPM

Maximum RPM It is very clear in how to use and how to build an RPM.

Unix Administration topics:

UUALA

Security

SANS Institute many good white papers

Matlab

Using MATLAB for presentation Many good tricks in making matlab figure better

Here is a list of resources that I found useful in studying different computer languages:

Summarized by David Wei Please contact me if you have comments.