Chapter 1
Subsections of Intro
Intro
This book is intended to be a Linux crash course used in induction training for new DevOps engineers. It contains knowledge I gained working as a System Engineer/Application Administrator/DevOps/SRE.
I am still deciding on the structure and what else to add.
Course Description
Linux for DevOps Engineers
Duration: 2 days | 3-4 hours/day
Purpose
This course is designed to help you quickly get started with learning Linux as an Application Administrator or DevOps Engineers. Beginning with understanding Linux from an OPS perspective you will learn about Linux filesystem and permissions, processes, basic and advanced commands useful for debugging os/application issues.
- Day 1 – QuickStart, Basic Commands, Filesystem
- Day 2 – Permissions, Processes, Advanced commands
Audience
This course is designed for technical professionals who require the skills to administer applications deployed on Linux systems.
Prerequisites
None.
Lab
In this course, we will use Ubuntu 20.04 a free resource from katakode.com
https://www.katacoda.com/scenario-examples/courses/environment-usages/ubuntu-2004
Quick Start
Don’t
- Make the user
root(system administrator’s account) accessible via ssh. - Run applications as root, applications might contain a vulnerability if the application is compromised it can run malicious code as root.
- copy/paste
rm select * from ...in your console, careful with what you have in your system clipboard.
Avoid
- configuring server logins with user and password.
- using root user as a system admin, you can make mistakes.
- using globbing
*,*matches any string, including the empty string. eg:rm *
Shells
The shell is a program that takes commands from the keyboard and gives them to the operating system to perform. Shells are usually run via a terminal emulator, this is a program that opens a window and lets you interact with a shell.
Popular shells: bash, zsh, ksh, dash, sh
Using Bash features
| Key or key combination | Function |
|---|---|
| Ctrl+A | Move the cursor to the beginning of the command line |
| Ctrl+C | End a running program and return the prompt |
| Ctrl+D | Log out of the current shell session, equal to typing exit or logout |
| Ctrl+E | Move the cursor to the end of the command line |
| Ctrl+H | Generate backspace character |
| Ctrl+L | Clear this terminal |
| Ctrl+R | Search command history |
| Ctrl+Z | Suspend a program |
| ArrowLeft and ArrowRight | Move the cursor one place to the left or right on the command line |
| ArrowUp and ArrowDown | Browse history. Go to the line that you want to repeat, edit details if necessary, and press Enter to save time. |
| Tab | Command or filename completion |
| Tab Tab | Shows file or command completion possibilities |
Getting help
# man [command]
man ls # see manual for ls command
# command --help (long)
ps --help # print program help