pathname: root-name root-directoryopt relative-pathopt root-directory relative-pathopt relative-path
root-name: An operating system dependent name that identifies the starting location for absolute paths. [ Note: Many operating systems define a name beginning with two directory-separator characters as a root-name that identifies network or other resource locations. Some operating systems define a single letter followed by a colon as a drive specifier – a root-name identifying a specific device such as a disk drive. — end note ]
root-directory: directory-separator
relative-path: filename relative-path directory-separator relative-path directory-separator filename
filename: name dot dot-dot
name: A sequence of characters other than directory-separator characters. [ Note: Operating systems often place restrictions on the characters that may be used in a filename. For wide portability, users may wish to limit filename characters to the POSIX Portable Filename Character Set:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
a b c d e f g h i j k l m n o p q r s t u v w x y z
0 1 2 3 4 5 6 7 8 9 . _ - — end note ]
dot: The filename consisting solely of a single period character (.).
dot-dot: The filename consisting solely of two period characters (..).
directory-separator: slash slash directory-separator preferred-separator preferred-separator directory-separator
preferred-separator: An operating system dependent directory separator character. May be a synonym for slash.
slash: The slash character (/).
Multiple successive directory-separator characters are considered to be the same as one directory-separator character.
The filename dot is treated as a reference to the current directory. The filename dot-dot is treated as a reference to the parent directory. What the filename dot-dot refers to relative to root-directory is implementation-defined. Specific filenames may have special meanings for a particular operating system.