Practical UNIX

UNIX Command-Line Options, Arguments, and Comments

At the shell prompt, you are expected to enter commands to UNIX. A UNIX command can be a simple one-word command, such as this:

$ exit

Here, the exit command enables you to end the shell and go back to a login prompt. If exit doesn’t work, try the logout command or Ctrl+D instead:

$ date
Sun Mar 15 07:30:49 PST 1998
$

In this example, date is another simple one-word UNIX command. Most UNIX commands are all lowercase, although there are exceptions. You must use the proper case (uppercase versus lowercase) when entering commands in UNIX. Be especially wary of handwritten instructions containing UNIX commands. Many people always handwrite certain characters in uppercase or lowercase without remembering ...