This glossary is organised in alphabetical order, and focuses on definitions.



The administrator (or system administrator) is the person responsible for maintaining a computing system.



A directory is a filesystem cataloguing structure that contains references to files and/or other directories.

directory, current working

The current working directory (or working directory) is the directory in which a user or process is currently working.

directory, parent

The parent directory refers the directory one level above a given directory.

directory, root

The root directory is the top-level directory of the Linux file system.



A filesystem (or file system or fs) is a system of rules and structures that control how data is stored to and retrieved from data storage devices. There are several different types of filesystems available depending on the storage medium.



A pathname is the route taken along the filesystem tree to reach a specific directory or file.

pathname, absolute

An absolute pathname is a pathname that starts at the root directory.

pathname, relative

A relative pahtname is a pathname that starts at the working directory.



The shell is the command line interpreter program that provides the command line interface between human users and Unix-like systems.



A terminal is an electronic or electro-mechanical device used for entering data into, and displaying or printing data from, a computing system. Terminals were historically used for allowing inexpensive mutli-user access to expensive computing systems.

terminal emulator

A terminal emulator is a program running on a personal computer that emulates a traditional terminal, providing the shell to access the OS running on the computer. Terminal emulators can run both within and without GUIs. Several terminal emulator instances can run concurrently.

terminal window

A terminal emulator running within a GUI. Examples are xterm, urxvt, and GNOME Terminal.

terminal, virtual

A virtual terminal (or virtual console) is a terminal emulator running outside a GUI. Linux systems generally provide six virtual consoles that can be cycled through by pressing the ALT-F1 to ALT-F6 keys.