Changes

<ol><li value="4">To verify that you properly created those files, issue the following:<br><span style="color:blue;font-weight:bold;font-family:courier;">bash /home/murray.saul/myscripts/week3-check-3</span><br><br>If you encounter errors, then make corrections (eg. '''viewing directory contents''', '''check for correct filename syntax''',<br>'''case sensitivity''', '''missing files''', '''files in the wrong location''', etc.) and then re-run the checking script<br>until you receive a congratulations message, and then continue with this sectioninvestigation.<br><br><span style="color:red;">'''ATTENTION''':<br>Learning to '''fix your mistakes''' by issuing Linux commands may be required if you make mistakes<br>in your Assignment #1. This advice should help to prevent '''wasting time''' completing later sections of your assignment #1.</span><br><br><li>Issue the '''ls''' command to get a listing of files in your ''examples'' directory.<br><br>The output should look identical to the diagram displayed below.<br>You can refer to this listing to see all files so you can then predict the output from Linux commands that use filename expansion symbols.<br><br>[[Image:listing-1.png|left|650px|thumb|]]<br><br><br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls ???.txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls ?????.txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls ??????.txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls [0-9].txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.br>Did the command work?<br>What does this teach you about the character class [ ] symbol?<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls [0-9][0-9][0-9].txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls [a-z][a-z][a-z].txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command (using character class with UPPERCASE letters)?:<br><span style="color:blue;font-weight:bold;font-family:courier;">ls [A-Z][A-Z][A-Z].txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command (using character class using alpha-numeric characters)?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls [a-zA-Z0-9][a-zA-Z0-9][a-zA-Z0-9].txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer.<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls *.txt</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer. Did ALL text files get listed? Why not?<br><br></li><li>What do you think the output will be from the following Linux command?<br><span style="color:blue;font-weight:bold;font-family:courier;">ls *.[tT][xX][tT]</span><br>'''Write down the expected output''' on paper, then '''issue the command''' to check your answer. Did ALL text files get listed this time? If so, why?<br><br></li><li>'''NOTE:''' We have just been using filename expansion symbols just with the ls command.<br>Filename expansion symbols can be used for ANY Linux file management command (e.g. '''cat''', '''more''', '''less''', '''cp''', '''mv''', '''rm''', '''ls''', etc.).<br><br>Let's get some practice issuing these other Linux file management commands.<br><br></li><li>Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">file *.[tT][xX][tT]</span><br>What is the purpose of this command? Which files are contained in this output?<br><br><li>[[Image:dir12.png|right|350px|thumb|]]Change to the '''commands''' directory using an '''absolute''' pathname<br>(use the diagram on right-side for reference).<br><br></li><li>Issue a Linux command to confirm that you are now in the '''commands''' directory.<br><br></li><li>Issue the following Linux command (lowercase "l" NOT the number "1"):<br><span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/l* &nbsp; .</span><br>View the contents of the contents directory. What did this command do?<br><br></li><li>Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">rm *</span><br><br>View the contents of the contents directory. What did this command do?<br><br></li><li>Issue the following Linux command (lowercase "l" NOT the number "1"):<br> <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/l? &nbsp; .</span><br>View the contents of the contents directory. What did this command do?<br><br></li><li>Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">rm l[!s]</span><br>View the contents of the contents directory. What did this command do?<br><br></li><li>Use a text editor (nano or vi) to create the file called '''ab''' in the '''commands''' directory that contains the line of text below,<br>and then save editing changes to this file:<br><span style="font-family:courier;">This is file ab</span><br><br></li><li>Use a text editor (nano or vi) to create the file called '''cd''' in the '''commands''' directory that contains the line of text below,<br>and then save editing changes to this file:<br><span style="font-family:courier;">This is file cd</span><br><br></li><li>Use a text editor (nano or vi) to create the file called '''ef''' in the '''commands''' directory that contains the line of text below,<br>and then save editing changes to this file:<br><span style="font-family:courier;">This is file ef</span><br><br></li><li>Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">cat ??</span><br><br>View the contents of the contents directory. What did this command do? Why does the output look strange?<br><br>'''NOTE:''' Press the keys '''ctrl-c''' to return to the shell prompt.<br><br></li><li>Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">cat [!l][!s]</span><br><br>View the contents of the contents directory. What did this command do? Does the output look better? If so, why?<br><br></li></ol>

As discussed in the above sectioninvestigation, there are some special characters that the shell uses to perform an operation<br>including the filename expansion symbol: '''*''' 

In this sectioninvestigation, you will learn '''three unique methods''' to quote special characters.