Linux & the Command Line
The operating system behind most servers and security tooling, and how to drive it from the terminal.
1. Introduction to Linux
Why Linux matters for security work: it runs almost every server on the internet, and it's operated through the terminal.
2. Navigating the Filesystem
pwd, ls, and cd — finding out where you are, seeing what's around you, and moving between folders.
3. Working with Files
mkdir, touch, cp, mv, and rm — creating, copying, renaming, and removing, and why rm has no undo.
4. Viewing & Editing Files
cat, less, and nano — reading and editing text without leaving the terminal.
5. Permissions
chmod and chown — controlling who can read, write, and execute a file, and why misconfigured permissions are a real security issue.
6. Processes
ps, top, and kill — seeing what's running on a machine, and stopping something that's misbehaving.
7. Piping & Redirection
Chaining commands together with | and sending output to a file with > — the idea that makes the command line genuinely powerful.
8. Package Management
Installing and updating software from the command line — apt on Debian/Ubuntu, and why updating first matters.