A file is the basic unit in the SunOS operating system. Almost everything is treated as a file, including the following items.
Documents – These items include text files, such as letters or reports, computer source code, or any other document that you write and want to save.
Commands – Most commands are executable file. That is, they are files you can execute to run a particular program. For example, the date command in the previous chapter, which executes a program that provides the current date, is an executable file.
Devices – Your terminal, printer, and disk drive(s) are all treated as files.
Directories – A directory is simply a file that contains other files.
The following section explains the commands for creating, listing, copying, moving, and deleting files. This section also includes information on how to list the contents of a file and how to determine the nature of a file.