(241) Master SHELL SCRIPTING in ONE VIDEO for Beginners 🔥 [HINDI] | MPrashant

Introduction

  • Complete course on shell scripting starting from basics.

  • Over 40 scripts and more than 5 hours of content, including real-life projects.

Basics of Shell

  • Hardware: CPU, RAM, and storage devices.

  • Operating systems enable the interaction with hardware through commands.

  • Terminal: A user interface for executing commands.

  • Common shell types: Bash (most common), SH, KSH, CSH, TCSH, and ZSH.

Shell Scripting Overview

  • Shell scripting consists of a series of commands to automate tasks.

  • The script is an executable file that can consolidate multiple commands.

  • Scripts facilitate the automation of repetitive tasks, saving time and effort.

  • Scripts can be scheduled to run at specific times, eliminating the need for constant monitoring.

Writing Your First Script

  • Creating a simple "Hello World" script:

    • Use #! followed by the path to the shell (e.g., #!/bin/bash).

    • Use the echo command to display text.

  • Use touch to create a new script file and chmod +x to make it executable.

  • Running the script can involve checking for execution permissions.

Comments in Scripts

  • Use # for single-line comments and : ' ': for multi-line comments.

Variables in Shell Scripting

  • Variables are containers for storing data.

  • To create a variable, use: variable_name=value.

  • Access a variable with $variable_name.

  • Example: using variables for user data in scripts.

Conditionals and Logic

  • Writing if statements to control the flow based on conditions.

  • Usage of logical operators: &&, ||, and ! for combining conditions.

  • Using elif for multiple conditional branches.

  • Commands can be tested for success or failure using exit statuses.

Loops in Shell Scripting

For Loops

  • Syntax for loops:

    for variable in list
do
    commands
done

  • Loop through files, directories, or a sequence of numbers.

While Loops

  • The syntax allows for executing as long as a condition is true:

    while [ condition ]; do
    commands
done

Until Loops

  • Executes until the condition is true:

    until [ condition ]; do
    commands
done

Functions

  • Functions encapsulate reusable pieces of code:

    • Define a function using function_name() { commands }.

    • Call a function by its name.

    • Utilize parameters within functions to receive input data.

Error Handling and Debugging

  • Use set -e to exit on errors, enhancing reliability.

  • Utilize logging for tracking execution.

  • Use trap to handle signals and clean up during script execution.

Cron Jobs and Scheduling

  • Use cron for scheduling tasks:

    • Access the crontab with crontab -e.

    • Schedule scripts to run at defined intervals.

Conclusion

  • Shell scripting is a powerful tool for automating repetitive tasks and managing system operations.

  • Understanding the basic syntax and functionalities enables effective script writing.