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→INVESTIGATION 3: COMMAND SUBSTITUTION / MATH OPERATIONS
# To demonstrate the need for the '''( )''' construct, issue the following:<br><span style="color:blue;font-family:courier;font-weight:bold">echo "1 + 2"</span><br><br>What did you notice?<br><br>
# Issue the following (using that math construct):<br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((1 + 2))"</span><br><br>What did you notice?<br>The '''$''' in front of the construct '''expands''' the result of the calculation.<br><br>
# Issue the following commands demonstrating other types of math calculations:<br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((2 - 3))"</span><br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((2 * 3))"</span><br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((2 / 3))"</span><br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((2 ** 3))"</span><br><br>'''NOTE:''' You may notice that '''dividing''' '''2''' by '''3''' shows a '''zero''' result. To perform decimal calculations would require<br>the use of other commands such as '''awk''' or '''bc''' (that technique '''NOT''' covered in this course).<br><br>You can use this math construct with variables as well.<br><br># xIssue the following commands demonstrating using the math construct with variables:<br><span style="color:blue;font-family:courier;font-weight:bold">num1=34</span><br><span style="color:blue;font-family:courier;font-weight:bold">num2=12</span><br><span style="color:blue;font-family:courier;font-weight:bold">echo "$((num1 * num2))"</span><br><br>What did you notice?<br><br>
=INVESTIGATION 4: USING CONTROL FLOW STATEMENTS =
