Let's start with the opening act!

Users

Standard User

Super User / Administrator

 

Root

Why?

  • Better control
  • Restricted Permissions
  • Multiple users can work in synchrony

Restricted Permission?

How?

Groups

Group ID: A
Users: a, b, c

Group ID: B
Users: b, c

Group ID: C
Users: c

Permissions

Read

Write

Execute

4

2

1

Demo Time!

  • `ls -l`
  • whoami
  • groups
  • id
  • su
  • sudo
  • sudo id
  • chmod

User management

create/remove users

User details stored

Action Command
Create user `useradd <user>`
Change Password `passwd <user>`
Modify user `usermod -L <user>`
`usermod -U <user>`
Delete user
Adding new group `groupadd -g 4001 <group> `
Add user to new group `usermod -aG <group> <user>`

Cheat Sheet !

Softwares and packages

Why do we need software?

How to install software?

Package managers

The software to install software

But why?

Dependencies

Package manager

Demo Time!

  • sudo dnf install vim
  • man dnf
  • dnf search <package-name>
  • dnf list updates
  • dnf updateinfo list --security
  • dnf update

Bash

The bourne Shell

How to access shell?

Terminal Emulators

Shell Scripts

Shell scripts?

A script/file with shell (bash) instructions

But why?

Demo time!

SSH

Secure Shell Protocol

Port: 22

What is SSH?

  • Network Protocol used for remote administration

  • Created in 1995 by Tatu Ylönen, SSH protocol

  • Uses Public-key based authentication for controlled access

Why SSH?

And

Alternatives?

rlogin

telnet

ftp

How it works?

How to connect?

  • SSH client
  • Access permission (User and password)
  • Server address (IP/URL)

ssh <user>@<ip-address>

-v: verbose

-i: identify file (.pem file)

Processes & Services

  • Each program in execution is a process
  • All processes are tracked by Operating system
  • Linux keep process details in /etc/proc

Lifecycle of process

Process management?

View all active processes

ps

-a: all process

-u: for users in userlist

Services

Set of processes

How to manage services?

systemd

Systemd: service manager

  • Check status
  • Start service
  • Stop service
  • Control service

systemd

status

<service>

start

stop

enable

Logging

Questions?

Thank you!

Kernel (Drivers)

LearningTheLinux

By Mohit Bansal

LearningTheLinux

A filler talk on how open source evolved over time and how git came into picture. The skills that can be useful to start contributing in open source, both technical and non-technical.

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