Command Line Interface

Image of a terminal prompt

What’s a Terminal/Console/Command Line/CLI?

In some parts of this site, you may see references to using the Console, Terminal or CLI. What this means is that you are required to use a text-mode command system, rather than a graphical command system to perform actions. In most Linux systems, the command line interface can be accessed by looking in your Applications menu and searching for ‘Terminal’. Other apps such as Xterm, Rxvt, Konsole and others exist, but they all generally do the same thing.

So, why should I use a CLI?

Commands used to be the way that all computers were operated. Since the beginning of keyboards and monitors, computers required users to provide text based instructions to do things like work on files or use applications. A command interface is often abbreviated to CLI (Command Line Interface or Interpreter). The commands you give are usually entered using a piece of software called a Terminal or Console. This software is usually a small tool such as the Gnome Terminal, xterm, rxvt or the Linux Console which traditionally runs the Bash (Bourne Again Shell) in Linux. The commands you give to the bash shell are interpreted to provide outcomes. Here’s an example: At the command prompt (usually denoted by something like username$) , typing something like ‘chmod u=rwx file.txt‘ (without the parenthesis) would change the ownership permissions of the file called file.txt to be readable, writable and executable by the owner of the file (user).

Today of course, most computers are synonymous with the use of a Graphical User Interface or GUI, which uses Windows, Icons, Menus and Mouse pointers (WIMP) to operate the computer rather than commands, however many systems administrators and power users in both Windows and Linux worlds still prefer to use a command line interface to quickly perform actions. It’s a great time saver once mastered!

Question MarkThe Terminal application can be run by pressing Ctrl+Alt+T (Ubuntu and similar) or clicking the icon in your Applications > Accessories menu, or pressing the Windows key to enter the apps dash and typing terminal, then press return.

If you want to know about some of the commands which you can type in at the Terminal, check out the commands tutorial.

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