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→INVESTIGATION 3: USING CONTROL FLOW STATEMENTS IN SHELL SCRIPTS
# To generate a test error, issue the improper use of the '''test''' command:<br><span style="color:blue;font-weight:bold;font-family:courier;">[$number1 -gt $number2]</span><br><br>You should notice an test error message.<br><br>
# Issue the correct use of the '''test''' command:<br><span style="color:blue;font-weight:bold;font-family:courier;">[ $number1 -gt $number2 ]</span><br><br>Issue a command to view the value of the exit status of the previously issued '''test''' command. You should notice that is works properly.<br><br>'''Let's now learn about control-flow statements:'''<br><br>'''Logic statements''' are to create different paths or directions that the script can execute based in the result of testing conditions. In this tutorial, we will only focus on the '''if''' logic statement.<br><br>
# Use a text editor like vi or nano to create the text file called '''if-1.bash''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">vi if-1.bash</span>)<br><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># Enter the following lines in your shell script:<br><span style="font-family:courier;">#!/bin/bash<br>clear<br>num1=5<br>num2=10<br>if [ $num1 -gt $num2 ]<br>then<br> echo "Greater Than"<br>fi</span><br><br># Save your editing session and exit the text editor (eg. with vi: press '''ESC''', then type ''':wx''' followed by '''ENTER''').<br><br># Issue the following linux command to add execute permissions for your shell script:<br><span style="color:blue;font-weight:bold;font-family:courier;">chmod u+xif-1.bash</span><br><br># Re-run your shell script: <span style="color:blue;font-weight:bold;font-family:courier;">./if-1.bash</span><br><br>
= LINUX PRACTICE QUESTIONS =
