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→INVESTIGATION 2: ADDITIONAL LOOPING STATEMENTS
# Set execute permissions for this shell script and run your shell script by issuing: <span style="color:blue;font-weight:bold;font-family:courier;">./for-6.bash</span><br><br>What do you notice? You should have noticed an error message.<br><br>
# To demonstrate what went wrong, issue the following commands:<br><br><span style="color:blue;font-weight:bold;font-family:courier;">num1=5;num2=10<br>result=$num1+$num2<br>echo $result<br><br></span><br><br>Notice that the user-defined variable stores the text "10+5" which is <u>NOT</u> the expected result of adding the number 10 and 5.<br><br>As you may recall in class, we need to convert a number stored as text into a '''binary number''' for calculations (in this case, advance the value by 1 for each loop). We can accomplish this by either using the expr command, or by surrounding our math operation within a set of two round brackets.<br><br>
# To demonstrate, issue the following set of commands:<br><br><span style="color:blue;font-weight:bold;font-family:courier;">num1=5;num2=10<br>resultsum=$( expr $num1+$num2)<br>echo $resultsum<br><br>((resultproduct=$num1+*$num2))<br>echo $resultproduct</span><br><br>Let's apply this technique we just learned to correct our recently created shell script.<br><br>
# Use a text editor like vi or nano to edit the text file called '''for-6.bash''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">vi for-6.bash</span>)<br>If you are using the nano text editor, refer to notes on text editing in a previous week in the course schedule.<br><br>
# Change line 6 to the following:<br><span style="color:blue;font-family:courier;font-weight:bold;">((value=value+1))</span><br><br>