![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.](https://image.slidesharecdn.com/bwubta22508csd-241008140819-854cc68a/85/BWU_BTA_22_508_cSd-how-os-are-implemented-pptx-8-320.jpg)
BWU_BTA_22_508_cSd how os are implemented.pptx
- 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