Linux Fundamentals

This is a reference guide for navigating and managing a Linux-based system

Author: Sean Alvarado , 2026-2-27

Navigation and File Management

pwd: Print Working Directory - shows your current location.

ls -la: Lists all files, including hidden ones, with detailed information.

cd : Changes the directory.

mkdir : Creates a new directory. rm -rf : Forcefully removes a file or directory.

Permissions and Security

chmod 400 <key.pem>: Sets read-only permissions for the owner (required for SSH keys).

chown : : Changes the owner and group of a file.

sudo : Executes a command with administrative (root) privileges.

System and Connectivity

ssh -i <key.pem> @: Connects to a remote server securely.

cat : Displays the contents of a file in the terminal.

grep "search_term" : Searches for a specific string within a file.