Introduction to Shell Scripting - RHCSA+.pdf
0 likes170 views
![Conditional Statements
● Uses if-else statements to check if a user's number is greater than 10
● Uses basic conditional operators (-gt) and keywords (if, then, else, fi) to make
decisions based on input
● If-Then: Conditional execution of code.
Syntax:
`if [ condition ]; then action; fi`](https://image.slidesharecdn.com/introductiontoshellscripting-rhcsa-250217073722-b09fc1de/85/Introduction-to-Shell-Scripting-RHCSA-pdf-7-320.jpg)
Introduction to Shell Scripting - RHCSA+.pdf
- 2. Shell Scripts Executable file comprising a series of shell commands executed in sequence. Within the file, you can include: ● Shell declaration (#!/bin/bash) ● Commentary lines (# comments) ● Various commands (echo, cp, grep, etc.) ● Control statements (if, while, for, etc.) ● Ensure executable permissions (e.g., -rwx r-x r-x) ● Call script using absolute path (e.g.,-/home/userdir/script.bash) ● Calling from the current directory, use ./script.bash
- 3. Getting Started with Shell Scripts ● touch hello.sh - creates an empty text file ● Shebang line (#!/bin/bash) specifies bash as the interpreter for executing our script commands.
- 4. ● Shell script structure-combines shebang (#!/bin/bash) and echo commands to perform tasks, executed using ./scriptname.sh ● chmod +x hello.sh - makes script executable, allowing it to run as a program
- 5. Working with Variables and User Input ● Script that collects user input using read variable and displays a personalized greeting message ● Uses basic commands (read, echo) and variables
- 6. ● chmod +x user_input.sh -Adds execute permissions to transform the script into a directly runnable program file. ● ./user_input.sh -Executes the script from the current directory
- 7. Conditional Statements ● Uses if-else statements to check if a user's number is greater than 10 ● Uses basic conditional operators (-gt) and keywords (if, then, else, fi) to make decisions based on input ● If-Then: Conditional execution of code. Syntax: `if [ condition ]; then action; fi`
- 9. ● chmod +x conditional.sh -Makes the script executable ● ./conditional.sh -Runs the script and verify that it evaluates user input against the condition, and display appropriate message based on the number comparison.