BWU_BTA_22_508_cSd how os are implemented.pptx

something about os

1. NAME- RANJAN DAS STUDENT CODE- BWU/BTA/22/508 DEPARTMENT- B.TECH CSE(AIML) SEC- I SEM - 4th SUBJECT NAME- OPERATING SYSTEM SUBJECT CODE- PCC-CSM401 TOPIC NAME- SHELL PROGRAMING

2. Contents Introduction Type of shells Shell scripting Basics of shell scripting Uses of shell scripting

3. WHAT IS A SHELL A shell is a program that takes commands typed by the user and calls the operating system to run those commands. * A shell is a program that acts as the interface between you and the Linux system, allowing you to enter commands for the operating system to execute. * Shell accepts your instruction or commands in English and translate it into computers native binary language.

4. WHY WE USED SHELLS We can use shell scripts to automate administrative tasks. * Encapsulate complex configuration details. * Get at the full power of the operating system. * The ability to combine commands allows you to create new commands * Adding value to your operating system.

5. Types of shells Bourne shell C shell Korn shell Bash shell Tcsh shell

6. Shell Scripting Shell scripting is a way to automate tasks using the command-line shell of an operating system. The shell is a program that interprets commands and acts as an intermediary between the user and the operating system. It is a series of command stored in a plain text file. A Shell script is similar to a batch file in MS-DOS but is much more powerful than that.

7. Basics of Shell Scripting: Shebang Line: Every shell script should begin with a shebang line ( #! ) followed by the path to the shell interpreter. For example, #!/bin/bash indicates that the script should be executed using the Bash shell. Comments: Comments start with a # and are ignored by the shell. They are used to add explanations or documentation to the script. Variables: Variables are used to store data. They can be defined and accessed using the $ symbol. Ex-  NAME="John" echo "Hello, $NAME!"

8. Control structures Shell scripting supports various control structures like loops and conditionals ( if , else , elif , case ). Here's an example of an if-else statement. Ex- if [ "$NAME" == "John" ]; then     echo "Hello, John!"    else     echo "Hello, someone else!"    fi # fi used to denote the end of a conditional block.

9. Functions We can define functions to organize our code and reuse it. We can perform various type of operation in a program using functions. Ex- greet() {     echo "Hello, $1!" } greet "Alice" o/p- Hello, Alice. Square() {       Local num=$1       Local result=$((num * num))       echo "The square of $num is: $result" } Square 5 o/p- The square of 5 is: 25

10. Examples where shell scripting can be used: Monitoring Linux system Data backup & create snape shots. To find out available memory & free memory. Find out all necessary networks are running out or not.

11. Thank you