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Tutorial12: Shell Scripting - Part 2

461 bytes removed, 08:58, 29 July 2020
INVESTIGATION 2: ADDITIONAL LOOPING STATEMENTS
# Use the '''more''' command to view the contents of the text file called '''for-1.bash''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">more for-1.bash</span>)<br><br>As you should have noticed from ''tutorial 10'' that the '''for''' loop can use a list.<br>You can also use the for loop with positional parameters stored as arguments from an executed shell script.<br>We will revisit this now.<br><br>
# Use the more command to view the text file called '''for-2.bash''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">more for-2.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>for x<br>do<br>&nbsp;&nbsp;&nbsp;echo $x<br>done<br>echo "blast-off!"</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+x for-2.bash</span><br><br># Run your shell script by issuing: <span style="color:blue;font-weight:bold;font-family:courier;">./for-2.bash 10 9 8 7 6 5 4 3 2 1</span><br><br>How does this differ from You should notice the script looped for each argument following the previous shell script?.<br><br>You will learn in can also use the for loop with a couple of weeks more examples of list using '''command substitution''' - this is an effective technique to loop statementswithin a shell script.# First, you need to learn how to use command substitution to store arguments as positional parameters.<br><br>
# After you complete the Review Questions sections to get additional practice, then work on your<br>online assignment 3.
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In the next investigation, you will ...
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