The Basis of UNIX

Most everything in UNIX comes down to files and directories. If you understand the hierarchical UNIX file system layout and how to manipulate files and directories, then you're a long way toward UNIX understanding. In this and upcoming chapters you'll see examples from several UNIX variants as well as Linux.

A lot goes into working with UNIX files and directories. This chapter covers the basics and background of files and directories in UNIX, including:

• The file command

• The ls command

• The file system layout

There are references to a number of UNIX operating systems in this chapter, including Linux, because the commands covered apply to most all UNIX variants.

The next chapter, Chapter 21, covers commands related to files and directories. The only commands covered in this chapter are the file and ls commands. file is used to determine the type of file and ls is used to list files and directories.