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→INVESTIGATION 2: ADDITIONAL LOOPING STATEMENTS
# Enter the following lines in your shell script:<br><span style="color:blue;font-weight:bold;font-family:courier;"><br>#!/bin/bash<br>value=1<br>while [ $value -le 5 ]<br>do<br> echo "$value"<br> value=value+1<br>done<br></span><br>
# Save your editing session and exit the text editor (eg. with vi: press '''ESC''', then type ''':wx''' followed by '''ENTER''').<br><br>
# 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 $result<br><br></span>Notice that the user-defined variable stores the text "'''10+5'''" which is <u>NOT</u> the expected result of adding the number 10 and 5.<br><br>As you may recall in class, we need to convert a number stored as text into a '''binary number''' for calculations (in this case, advance the value by 1 for each loop). We can accomplish this by either using the expr command, or by surrounding our math operation within a set of two round brackets.<br><br>
# To demonstrate, issue the following set of commands:<br><br><span style="color:blue;font-weight:bold;font-family:courier;">num1=5;num2=10<br>sum=$(expr $num1+$num2)<br>echo $sum<br><br>((product=$num1*$num2))<br>echo $product</span><br><br>Let's apply this technique we just learned to correct our recently created shell script.<br><br>
