Lab Report: Enhancing Command Efficiency with Bash and Red Hat Enterprise Linux Utilities

Name: Abigail Hall
Date: 06/28/24

Objectives

• Run commands more efficiently using advanced features of the Bash shell, shell scripts, and Red Hat Enterprise Linux utilities.

• Run repetitive tasks with for loops.

• Evaluate exit codes from commands and scripts.

• Run tests with operators and create conditional structures with if statements.

• Create and apply regular expressions to match data in text files.

• Use grep to search files and data from piped commands.

Sections

1. Write Simple Bash Scripts

Guided Exercise:

1. Create a Simple Bash Script:

Open a terminal and use a text editor to create a new file named simple_script.sh.
use code
nano simple_script.sh

Add the following content to the file:
use code
#!/bin/bash

echo "Hello, World!"

1. • Save the file and exit the editor.

2. Make the Script Executable:

Change the file permissions to make the script executable:
use code
chmod +x simple_script.sh

3. Run the Script:

Execute the script to verify its output:
use code
./simple_script.sh

2. Loops and Conditional Constructs in Scripts

Guided Exercise:

1. Create a Script with a For Loop:

Create a new script named loop_script.sh:
use code
nano loop_script.sh

Add the following content to the file:
use code
#!/bin/bash

for i in {1..5}

do

  echo "Iteration $i"

done

1. • Save and exit the editor.

Make the script executable:
use code
chmod +x loop_script.sh

Run the script:
use code
./loop_script.sh

2. Create a Script with Conditional Constructs:

Create a script named conditional_script.sh:
use code
nano conditional_script.sh

Add the following content to the file:
use code
#!/bin/bash

number=10

if [ $number -gt 5 ]

then

  echo "The number is greater than 5."

else

  echo "The number is 5 or less."

fi

2. • Save and exit the editor.

Make the script executable:
use code
chmod +x conditional_script.sh

Run the script:
use code
./conditional_script.sh

3. Match Text in Command Output with Regular Expressions

Guided Exercise:

1. Use Regular Expressions with grep:

Create a text file named sample.txt with sample data:
use code
nano sample.txt

Add some text lines to the file:
use code examples
apple

banana

cherry

apple pie

banana split

1. • Save and exit the editor.

2. Search for Text with grep:

Use grep to search for lines containing the word "apple":
use code
grep "apple" sample.txt

This command will output:

apple

apple pie

3. Use Regular Expressions for Pattern Matching:

Search for lines that start with a vowel using a regular expression:
use code
grep "^[aeiou]" sample.txt

3. • This will return any lines beginning with a vowel.

Advanced Commands and Techniques

1. Evaluate Exit Codes:

Test a command and check its exit code:
use code
ls /nonexistent-directory

echo $?

1. • The exit code 2 indicates that the directory does not exist.

2. Test Operators in Scripts:

Modify conditional_script.sh to use more operators:
use code
#!/bin/bash

number=10

if [ $number -gt 5 ] && [ $number -lt 15 ]

then

  echo "The number is between 5 and 15."

elif [ $number -eq 10 ]

then

  echo "The number is exactly 10."

else

  echo "The number is outside the specified range."

fi

2. • Save and run the updated script.

3. Use htop for Monitoring:

Install htop if not already installed:
use code
sudo yum install htop

Run htop to monitor system performance interactively:
bash
Copy code
htop

Results

By following these exercises, I have gained practical experience in writing and executing Bash scripts, using loops and conditionals, applying regular expressions, and managing system resources. These skills will significantly improve my efficiency in managing and automating tasks on Unix-like systems.

Conclusion

This lab provided hands-on experience with advanced Bash features and Red Hat Enterprise Linux utilities, enhancing my ability to perform repetitive tasks, evaluate command outcomes, and apply text-processing techniques. Mastery of these tools is essential for efficient system administration and scripting.

Future Improvements

• Explore more complex Bash scripting techniques and utilities.

• Integrate scripts with cron jobs for automated tasks.

• Experiment with advanced regular expressions for complex text processing.