Entry Points
Despite the essential differences of all programming languages, they share at least one thing in common: an entry point. An entry point is exactly what it sounds like: an entry into the program where the code begins execution. Historically speaking, the entry point is a function (method, procedure, routine, etc) with the name (or some variation of) main. Incidentally, due to this convention the main source file for the project is traditionally called main. However, in certain cases (with languages like brainfuck or bash), the entry point can become a little non-standard. Instead execution starts at the very beginning of the source file. In cases where the entry point is a function, command line arguments are typically recieved there.
Examples: