Linux Command Series Terminology

Learn the essential Linux terminology to understand and use Linux commands effectively.

Linux Command Series Terminology  

Understanding Linux terminology is crucial for mastering Linux commands. This guide explains essential terms used throughout the Linux Command Series.

File System  

Directory  

A directory is a folder that contains files and other directories. In Linux, directories are organized in a hierarchical structure.

# Example: Creating a directory
mkdir my_directory

File  

A file is a collection of data stored on disk. Files can be text, executable programs, or any other type of data.

# Example: Creating a file
touch my_file.txt

Path  

A path is the location of a file or directory in the file system. Paths can be absolute (starting from the root directory) or relative (relative to the current directory).

# Example: Absolute and relative paths
cd /home/user/documents  # Absolute path
cd documents             # Relative path

Users and Groups  

User  

A user is an account that can log in and execute commands on a Linux system. Each user has a unique username and home directory.

# Example: Creating a user
sudo useradd new_user

Group  

A group is a collection of users with common access permissions. Users can belong to multiple groups.

# Example: Creating a group
sudo groupadd new_group

Permissions  

Read, Write, Execute  

Permissions determine who can read, write, or execute a file or directory. Permissions are set using chmod and viewed using ls -l.

# Example: Viewing and setting permissions
ls -l my_file.txt
chmod 755 my_file.txt

Processes  

Process  

A process is an instance of a running program. Each process has a unique process ID (PID).

# Example: Viewing processes
ps aux

PID  

The Process ID is a unique identifier for each running process.

# Example: Finding a PID
ps -ef | grep my_program

Networking  

IP Address  

An IP address is a unique identifier for a device on a network. It can be static or dynamic.

# Example: Displaying IP address
ifconfig

Port  

A port is a logical endpoint for communication in a network. Ports are used to distinguish different services running on the same device.

# Example: Checking open ports
netstat -tuln

Package Management  

Package  

A package is a compressed file containing software and its dependencies. Packages are managed using package managers like apt or yum.

# Example: Installing a package
sudo apt-get install package_name

Repository  

A repository is a server that stores software packages and their metadata. Package managers use repositories to download and install packages.

# Example: Adding a repository
sudo add-apt-repository ppa:repository_name

Conclusion  

Understanding these Linux terms will help you navigate and use Linux commands more effectively. Refer back to this terminology as you progress through the Linux Command Series.