5.3 Navigating the File System
5.3.1 Command-line syntax
When logged in at the command line or when using a terminal window, a shell prompt appears on the screen. For the Bourne and Korn shells, the shell prompt for a user is a dollar sign ($). For a C shell user, the prompt is a percent sign (%). At the shell prompt, you can type commands. Commands are instructions which tell the system to perform an action. Syntax refers to the structure of the command and specifies allowable options and arguments. -   

The general format for UNIX commands is: 

$ command [option(s)] [argument(s)]

Note: Items in square brackets are optional, meaning they are not always required.

A space must be used as a delimiter between each part of the command entered. Up to 256 characters can be entered on a single command line. UNIX commands are always lower case. Options are usually a single letter preceded by a hyphen (-), also called a dash or minus sign. Multiple options can be combined using only one hyphen. The option might be upper or lower case depending on the command. Many commands do not require all three parts. Multiple commands can be entered on one line by separating them with a semicolon (;). 

Figure illustrates some examples of UNIX commands with and without options and arguments.

Lab Activity (Adobe Acrobat Reader, 25 kB)
  Basic Command Line Syntax

In this lab, you will work with various UNIX commands to develop an understanding of UNIX commands and syntax.