Primitive input/output

There are a number of primitive commands that offer fine grain control for reading and writing information to and from a file. We do not provide extensive examples here because these commands are more useful when combined with the programming commands that are explored in later chapters.

Before discussing these commands, it is important to discuss the idea of a connector. A connector is a generic way to treat a data source. This can be a file, an HTTP connection, a database connection, or another network connection. In this section, we only explore one type of connector, that is, the basic text file connector. More information can be found using the help command, help(file). The file command is used to create a connector to a file. The arguments to the file command are similar to the fopen command found in the C language.

The most basic use of the file command requires that you provide a name of a file and the mode that will be used in manipulating the file. The mode...