An introduction to the GNU compiler collection (GCC) for programmers interested in developing and compiling open source software. The guide identifies the commands and options for compiling programs written in C, C++, Objective-C, Fortran, Java, and Ada. The second half of the book explains the function of utilities for manipulating object files, debugging code and packaging software, and lists command line options for compiling programs to run on a specific platform. The author has worked on the development team of several compiler projects.