Linux Bootcamp Series – 14/Dec/2019

Linux Bootcamp Series

Operating System

• OS acts as an interface between User/Application and Hardware
• OS can interact with multiple devices (Device Driver might be necessary). This interaction complexity is abstracted from users/Applications
• OS also gives some System Applications and User Applications.

Categories

• Desktop Operating Systems:
  • Example: Windows 10, Mac, Ubuntu Desktop, Fedora
  • Users interaction on this server has to be simple.
  • Generally GUI Based
• Server Operating Systems
  • Examples: Windows Server 2016, Ubuntu Server, RedHat Linux, Open SUSE
  • User interaction can be little bit complicated.
  • Generally Non-UI / Terminal Based.

Linux Operating System

• Linux works on Desktops/Servers/Embedded Systems etc…
• Linux Kernel is the key component
• A Distribution (Parent Distribution/Platform) is built on top of kernel. Popular Distributions are
  • Debian
  • RedHat
  • Andriod
  • SUSE
• Companies like canonical etc take these parent kernels and they build the distributions which are most widely use. Some of Widely Used Distributions are
  • Ubuntu
  • Centos
  • RHEL

Lab Setup:

• Ubuntu Linux Instance on AWS or Azure
• Windows:
  • Git For Windows

Connecting to Linux Machine

• Any Linux Machine can be connected using SSH Protocol.
• Windows:
  • Install Git For Windows
• SSH Command for LInux Machines with Username and Password

ssh username@ipaddress

• SSH Command for LInux Machines with Username and KeyFile(PEM)

ssh -i <path-to-pem>   username@ipadress

Important Things to Consider

• Shell:

  • Helps you interacting with OS/Kernel
  • Shell is a command line based
  • Examples
    • bash (Bourne Again Shell)
    • zsh

• Commands:

  • Commands perform some action.
  • Command has a syntax

  <command> <paramters>
  

• Parameters:

  • Parameters are of two kinds, Positional Parameters and Named Parameters.

• Positional Parameter:

  • directly entering the value of parameter
  • Examples:

  ping google.com 
  mkdir test
  mv /tmp /temp
  

• Named Parameter:

  • Will have associated name with every paramter you enter
  • Examples:

  ping -c 10 google.com
  # -c is named paramter which has a value of 10
  ansible-playbook --inventory hosts  test.yml
  # --inventory is named parameter which has value of hosts
  

  • Named parameters generally have two forms
    • short form:
      • eg: ansible-playbook -i hosts test.yml
    • long form:
      • eg: ansible-playbook –inventory hosts test.yml

• Manual:

  • Every Linux command has a help which is called as manual.
  • To look at manual of any command use

  man <command>
  

  • Examples:

  man ls
  

Sample Commands to be executed

1. Display Linux System Information
# Display Linux system information
uname -a

# Display kernel release information
uname -r

# Show which version of redhat installed
cat /etc/redhat-release

# Show how long the system has been running + load
uptime

# Show system host name
hostname

# Display the IP addresses of the host
hostname -I

# Show system reboot history
last reboot

# Show the current date and time
date

# Show this month's calendar
cal

# Display who is online
w

# Who you are logged in as
whoami

Create a folder structure use mkdir and touch

• ecommerceapp
  • src
    • main.py
  • test
    • main.py
  • docs
    • main.md
  • Readme.md