Changes

<ol><li value="4">Before proceeding, let's run a '''checking script''' to make certain that you created these regular files correctly.<br><br></li><li>Issue the following Linux command to run a checking script:<br><span style="color:blue;font-weight:bold;font-family:courier;">bash /home/murray.saul/scripts/week3-check-3</span><br><br>If you encounter errors, then make corrections(eg. viewing directory contents, check for filename syntax, case sensitivity, missing files, etc., and then re-run the checking script until you receive a congratulations message, and continue in this section.<br><br><span style="color:red;font-weight:bold;">ATTENTION: Learning to fix your mistakes by issuing Linux commands may be required if you make mistakes in your Assignment #1!</span<<br><br><li>Issue the '''ls''' command to get a listing of files in your commands 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>Issue the following Linux command: <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>Issue the following Linux command: <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>Issue the following Linux command: <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>Issue the following Linux command: <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. Did the command work? What does this teach you about the character class [ ] symbol?<br><br></li><li>Issue the following Linux command: <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>Issue the following Linux command: <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>Issue the following Linux command (using character class with UPPERCASE letters): <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>Issue the following Linux command (using character class using alpha-numeric characters): <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>Issue the following Linux command: <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>Issue the following Linux command: <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>Write down the expected output on paper, then issue the command to check your answer.<br><br><li>Change to the '''commands''' directory using an '''absolute''' pathname.<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: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/l.* .</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: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/l? .</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></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>