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llm1-lab5-exercise4
Exercise 4In this exercise you will re-write the above script using the expr command. “Expr” is used to perform simple calculations. First you will learn expr’s syntax from the command line. To use expr from the command line1. While still in the myscripts directory. Use expr to add three numbers. root@localhost myscripts# expr 2 + 800 + 1845 What is your output? You will rewrite the calculator script from exercise 3 using “expr” 2. Make sure you are still in the “myscripts” directory. 3. Launch your text editor again and type in the following commands. 1 #!/bin/bash 2. #this script will perform a simple addition using expr 3. first_num=0 4. second_num=0 5. echo "Please type in the first number " 6. read first_num 7. echo "Please type in the second number " 8. read second_num 9. 10. echo "$first_num plus $second_num equals `expr $first_num + $second_num`" The only thing we have done differently is to use “expr” to perform the calculation in the last line. 3. Save the code you typed in a file and call it “calc2.sh” 4. Change the permissions on the file you created to make it executable. Type [root@localhost myscripts]# chmod u+x calc2.sh 5. Run the script by typing
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