19.2.1 Pathname Components

A pathname has six components: a host, a device, a directory, a name, a type, and a version.

19.2.1.1 The Pathname Host Component

The name of the file system on which the file resides, or the name of a logical host.

19.2.1.2 The Pathname Device Component

Corresponds to the “device” or “file structure” concept in many host file systems: the name of a logical or physical device containing files.

19.2.1.3 The Pathname Directory Component

Corresponds to the “directory” concept in many host file systems: the name of a group of related files.

19.2.1.4 The Pathname Name Component

The “name” part of a group of files that can be thought of as conceptually related.

19.2.1.5 The Pathname Type Component

Corresponds to the “filetype” or “extension” concept in many host file systems. This says what kind of file this is. This component is always a string, nil, :wild, or :unspecific.

19.2.1.6 The Pathname Version Component

Corresponds to the “version number” concept in many host file systems.

The version is either a positive integer or a symbol from the following list: nil, :wild, :unspecific, or :newest (refers to the largest version number that already exists in the file system when reading a file, or to a version number greater than any already existing in the file system when writing a new file). Implementations can define other special version symbols.