General computing resources

C++

• http://www.learncpp.com/
• http://www.cplusplus.com/
• Introduction to C++: A video guided tutorial
• MIT OpenCourseWare Intro to C & C++

Fortran

• Fortran Wiki
• http://www.fortrantutorial.com/
• How to learn Fortran

Python

• http://www.codecademy.com/tracks/python
• http://www.learnpython.org/
• http://learnpythonthehardway.org/
• http://inventwithpython.com

Other

• Working as a Software Developer - useful read if you touch any code
• A Guide to Midnight Commander
• UNIX toolbox
• First 5 Minutes Troubleshooting A Server

gcc/g++/gfortran compiler flags

Here are some useful flags to use when developing a code, or trying to find why code crashes:

-Wall -Wextra -Wconversion -pedantic -ffpe-trap=zero,overflow,underflow,invalid 
-ffree-line-length-none -finit-local-zero -fbounds-check -fcheck-array-temporaries

Use man gcc to find details about each.

I often remove "underflow" from the list, since it just makes small floating point numbers to zero, but it is useful to know.