Block and character files define devices. The name of each file must be unique within the directory where it is stored. This insures that the file also has a unique path name in the file system. The operating system is case-sensitive which means it distinguishes between uppercase and lowercase letters in file names. File names should be as descriptive as possible.
Directories follow the same naming conventions as files.
Certain characters have special meaning to the operating system, and should be avoided when naming files. A file name is hidden from a normal directory listing if it begins with a . When the li command is entered with the -a flag, the hidden files are listed along with regular files and directories. The path name of a file consists of the name of every directory that precedes it in the file tree structure. Only the final component of a path name can contain the name of a regular file.