Shell Scripting Intermediate - RHCSA+.pdf
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![● The script begins with "#!/bin/bash", indicating it's a Bash script.
● Syntax: The loop uses 'while [ $count-le 5 ]; do', with 'done' as its closing
statement.
● Loop Purpose: Executes code repeatedly until count reaches 5
● Syntax for 'while' loop: Uses 'while [condition]; do action; done'
● Output: The script prints each count value in sequence, incrementing by 1](https://image.slidesharecdn.com/shellscriptingintermediate-rhcsa-250217073831-9b61387e/85/Shell-Scripting-Intermediate-RHCSA-pdf-6-320.jpg)
![● The script begins with "#!/bin/bash", indicating it's a Bash script.
● Input Structure: Uses 'read-p "prompt" variable' to capture user input
● Validation Syntax: Implements 'if [[ $variable =~ pattern ]]; then action; else
error; fi'
● Example Implementation: Shows number validation using 'if [[ $num =~
^[0-9]+$ ]]' with appropriate success/error messages](https://image.slidesharecdn.com/shellscriptingintermediate-rhcsa-250217073831-9b61387e/85/Shell-Scripting-Intermediate-RHCSA-pdf-12-320.jpg)
![● Shell scripts handle files using commands like touch, cat, cp, mv, and rm.
● Redirection (>, >>) and condition checks ([-f file ]) help manage files
efficiently.
● Example: Create a file, write text into it, and display its contents
Shell Script File Operations](https://image.slidesharecdn.com/shellscriptingintermediate-rhcsa-250217073831-9b61387e/85/Shell-Scripting-Intermediate-RHCSA-pdf-14-320.jpg)
Shell Scripting Intermediate - RHCSA+.pdf
- 2. Loop in Script ● Loop -Automates repeated actions to streamline script execution ● Example: Creates a basic 1-5 counting loop that prints numbers sequentially ● Output: Displays "Iteration X" where X is the current loop number (1-5)
- 3. Loop Syntax ● The script opens with "#!/bin/bash", identifying it as a Bash script. ● Syntax: The loop structure follows the format: 'for i in {1..5}; do', ending with 'done' ● Loop Purpose: Executes code repeatedly through iterations ● Syntax for 'for' loop: Uses 'for i in {start..end}; do action; done'
- 4. ● chmod +x loop.sh - Makes scripts executable ● ./loop.sh - The script executes by printing numbered outputs in sequence.
- 5. While Loops ● To display numbers 1 through 5 sequentially
- 6. ● The script begins with "#!/bin/bash", indicating it's a Bash script. ● Syntax: The loop uses 'while [ $count-le 5 ]; do', with 'done' as its closing statement. ● Loop Purpose: Executes code repeatedly until count reaches 5 ● Syntax for 'while' loop: Uses 'while [condition]; do action; done' ● Output: The script prints each count value in sequence, incrementing by 1
- 7. ● chmod +x while_loop.sh -grants execution permissions ● ./while_loop.sh -This script executes the script to display counting from 1 to 5.
- 8. Shell Script Function ● Reusable blocks of code that help organize and modularize scripts. ● Improve readability and maintainability by avoiding redundant code. ● Syntax : function_name() { # Commands} ● Parameters are passed like arguments in scripts: $1, $2, ..., $N represent positional parameters.
- 9. ● The script begins with "#!/bin/bash", indicating it's a Bash script. ● Function Definition: Uses 'functionName() { commands; }' structure ● Function Call: Executes as 'functionName argument'
- 10. ● chmod +x function.sh -Makes the function script executable by granting execution permissions. ● ./function.sh - Executes the function script which outputs "Hello, User!" as greeting message.
- 11. Shell Script Input Validation ● The script prompts for user input and stores it in 'num' variable for checking if it's a valid number. ● Using regex pattern matching and if-else logic, it validates the input and displays appropriate success or error message.
- 12. ● The script begins with "#!/bin/bash", indicating it's a Bash script. ● Input Structure: Uses 'read-p "prompt" variable' to capture user input ● Validation Syntax: Implements 'if [[ $variable =~ pattern ]]; then action; else error; fi' ● Example Implementation: Shows number validation using 'if [[ $num =~ ^[0-9]+$ ]]' with appropriate success/error messages
- 13. ● chmod +x input.sh -Makes the input validation script executable by granting execution permissions. ● ./input.sh - Executes the input validation script which prompts for a number and validates if it's numeric.
- 14. ● Shell scripts handle files using commands like touch, cat, cp, mv, and rm. ● Redirection (>, >>) and condition checks ([-f file ]) help manage files efficiently. ● Example: Create a file, write text into it, and display its contents Shell Script File Operations
- 15. File Operation Script Syntax ● The script begins with "#!/bin/bash", indicating it's a Bash script. ● File Creation: Uses 'touch filename' to create an empty file ● File Writing: Implements 'echo "text" > filename' to write content ● File Reading: Uses 'cat filename' to display file contents
- 16. ● chmod +x file.sh - The script requires execution permissions to run. ● ./file.sh -The script creates, writes to, and displays a test file's contents.