Modern UNIX file systems support the following types of file system objects:
Regular Files (S_IFREG)
Character Devices (S_IFCHR)
Block Devices (S_IFBLK)
Named Pipes (S_IFIFO)
Symbolic Links (S_IFLNK)
The C macro names given within parentheses are provided by the include file <sys/stat.h> (see stat(2)). You'll see more of these in Chapter 6, "Managing Files and Their Properties."
A regular file is generally what is most important to users of a system. It stores the data that the user wants to retrieve and work with at a later time. The UNIX file system presents this data as a continuous stream of bytes.
A regular file consists of any number of data bytes, from zero to some ...