Day 4

Session Summary – Shell Scripting Basics Timeline

00:00 – 00:45 | Session Start & Introduction to Shell Scripting

• Trainer checks students’ knowledge of scripting

• Introduction to shell scripting basics

• Reference to previous cron job automation task

00:45 – 02:40 | Why Shell Scripting is Used

• Real-world example: creating hundreds of users from a CSV file

• Manual vs automated user creation

• Interactive vs non-interactive user creation:

  • adduser

  • useradd with flags

02:40 – 05:30 | What is a Shell

• Different types of shells:

  • Bash

  • Zsh

• Shell as an interpreter

• Creating first script file

05:30 – 06:50 | First Script: Hello World

• Creating script file

• Permission issue explanation

• Adding executable permission:

  • chmod +x

• Running the script

06:50 – 10:20 | Variables in Shell Script

• Creating variables:

  • name

  • age

• Memory concept of variables

• Dynamic value replacement

• Example output with different values

10:20 – 11:40 | Taking User Input

• Using read -p to accept input

• Prompting user for name

• Displaying dynamic output

Input/Output & Redirection

11:40 – 13:50 | Output Redirection Basics

• Creating empty file

• Writing to file using:

  • > (overwrite)

13:50 – 15:30 | Append Redirection

• Using:

  • >> (append)

• Difference between overwrite and append

• Practical examples

15:30 – 17:20 | Input Redirection & Error Redirection

• Using < for input

• Standard output vs standard error

• Redirecting errors:

  • 2>

• Combining stdout and stderr:

  • 2>&1

Pipes and Command Chaining

17:20 – 20:10 | Pipe Concept (|)

• Using ps aux | grep mysql

• Filtering command output

• How pipe passes output to another command

20:10 – 22:50 | Practical Pipe Example

• Counting files using:

  • ls

  • grep

  • wc -l

• Real-world log file counting scenario

Conditional Statements

22:50 – 26:10 | If Condition Basics

• Writing a simple if condition

• Checking numeric values

• True vs false condition behavior

26:10 – 30:20 | If Condition with File Check

• Checking if file exists:

  • -f flag

• Printing message if file exists

• Real-world use case:

  • Validating CSV file before automation

Loops in Shell Scripting

30:20 – 33:40 | Introduction to Loops

• Need for loops in automation

• Example: processing CSV file rows

• Basic loop concept

33:40 – 36:20 | Looping Through Numbers and Files

• Iterating through values

• Reading file line by line

• Processing each line

36:20 – 39:20 | Practical Automation Example

• Reading user data from file

• Dynamically creating users

• Using variables inside loops

Loop Control Statements

39:20 – 42:00 | Break and Continue Concepts

• Using break to exit loop

• Using continue to skip iteration

• Example:

  • Skipping specific values

  • Real-world scenario: skip certain users

Best Practices & Advanced Concepts

42:00 – 45:30 | Learning Approach & Documentation

• Importance of fundamentals over memorization

• Using documentation and search

• Problem-solving mindset in scripting

45:30 – 48:20 | Practical Use Case with User Prompts

• Example:

  • Database backup script

  • Prompt before pushing backup to cloud storage

48:20 – 49:40 | DRY Principle & Functions

• Concept: Do Not Repeat Yourself (DRY)

• Using functions in scripts

• Plan to cover advanced scripting next session

Session Wrap-Up

49:40 – End | Summary & Closing

• Recap of shell scripting basics

• Practice instructions

• Q&A

• Session end