UNIX Basics

UNIX Basics

A command is a program that tells the Unix system to do something. It has the form:

command [options] [arguments]

An argument indicates on what the command is to perform its action, usually a file or series of files.

An option modifies the command, changing the way it performs.

Commands are case sensitive.

Options are generally preceded by a hyphen (-), and for most commands, more than one option can be strung together, in the form:

command -[option][option][option]

Any filename that ends with a slash (/) is a folder (UNIX calls these directories). Any filename that ends with an asterisk (*) is a program. Anything ending with an at sign (@) is a symbolic link, and everything else is a normal, plain file.

Advantages of UNIX

multitasking A multitasking computer is one that actually can run more than one

program, or task, at a time. By contrast, most personal computers lock you into a single

program that you must exit before you launch another.

multiuser Computers intended to have more than a single person working on them

simultaneously are designed to support multiple users, hence the term multiuser. By contrast,

personal computers are almost always single-user because someone else can’t be running a

program or editing a file while you are using the computer for your own work.