15 Operating-System Interface

The Scheme standard provides a simple mechanism for reading and writing files: file ports. MIT/GNU Scheme provides additional tools for dealing with other aspects of the operating system:

• Pathnames are a reasonably operating-system independent tool for manipulating the component parts of file names. This can be useful for implementing defaulting of file name components.
• Control over the current working directory: the place in the file system from which relative file names are interpreted.
• Procedures that rename, copy, delete, and test for the existence of files. Also, procedures that return detailed information about a particular file, such as its type (directory, link, etc.) or length.
• Procedures for reading the contents of a directory.
• Procedures for obtaining times in various formats, converting between the formats, and generating human-readable time strings.
• Procedures to run other programs as subprocesses of Scheme, to read their output, and write input to them.
• A means to determine the operating system Scheme is running under.