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Tutorial10: Shell Scripting - Part 1

4 bytes added, 09:30, 11 March 2021

→‎INVESTIGATION 3: COMMAND SUBSTITUTION / MATH OPERATIONS

# To demonstrate the need for the '''( )''' construct, issue the following Linux command from the shell: echo "1 + 2" What did you notice?

# Issue the following Linux commands (using the ''math construct''): echo "$((1 + 2))" What did you notice? The (( )) construct converted values '''1''' and '''2''' from ''text'' to '''binary numbers'''. The '''$''' in front of the construct '''expands''' the result of the calculation.

# Issue the following Linux commands demonstrating other types of math calculations: echo "$((2 - 3))" echo "$((2 * 3))" echo "$((2 / 3))" echo "$((2 ** 3))" '''NOTE:''' You may notice that '''dividing''' '''2''' by '''3''' shows a '''zero''' result. To perform decimal calculations would require the use the '''awk''' or '''bc''' Linux commands (we will '''NOT''' cover that method to work with ''decimal numbers '' in this course). You can use the ''math construct'' with variables as well.

# Issue the following Linux commands demonstrating using the ''math construct'' with variables: num1=34 num2=12 echo "$((num1 * num2))" What did you notice? You can create variables and assign them values in the ''math construct'' as well.

# Issue the following Linux commands demonstrating using the math construct with variables: num1=5 num2=3 ((result = num1 ** num2)) echo "The result is: $result"

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Tutorial10: Shell Scripting - Part 1

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