# Glossary

## A

**Absolute file path:** The full file path, which starts from the root

**Argument (Linux):** Specific information needed by a command

**Authentication:** The process of verifying who someone is

**Authorization:** The concept of granting access to specific resources in a system

## B

**Bash:** The default shell in most Linux distributions

## C

**Command:** An instruction telling the computer to do something

## F

**File path:** The location of a file or directory

**Filesystem Hierarchy Standard (FHS):** The component of the Linux OS that organizes data

**Filtering:** Selecting data that match a certain condition

**Foreign key:** A column in a table that is a primary key in another table 

## N

**nano:** A command-line file editor that is available by default in many Linux distributions

## O

**Options:** Input that modifies the behavior of a command

## P

**Permissions:** The type of access granted for a file or directory

**Principle of least privilege:** The concept of granting only the minimal access and authorization required to complete a task or function

**Penetration test (pen test)**: A *simulated attack* that helps identify vulnerabilities in systems, networks, websites, applications, and processes

## R

**Relative file path:** A file path that starts from the user's current directory

**Root directory:** The highest-level directory in Linux

**Root user (or superuser):** A user with elevated privileges to modify the system

## S

**Standard input:** Information received by the OS via the command line

**Standard output:** Information returned by the OS through the shell

## U

**Ubuntu**: An open-source, user-friendly distribution that is widely used in security and other industries

**Unified Extensible Firmware Interface (UEFI)**: A microchip that contains loading instructions for the computer and replaces BIOS on more modern systems

**User interface**: A program that allows the user to control the functions of the operating system

## W

**Wildcard**: A `special character` that can be substituted with any other character