cpp is the C preprocessor. It is used by the compiler to have the #include and #define and such statements expanded in the source files. g++ is the C++ compiler. gcc is the C compiler. It is used to translate the source code of a program into assembly code. gccbug is a shell script used to help create good bug reports. gcov is a coverage testing tool. It is used to analyze programs to find out where optimizations will have the most effect. libgcc* contains run-time support for gcc. libstdc++ is the standard C++ library. It contains many frequently-used functions. libsupc++ provides supporting routines for the c++ programming language.