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{{Admon/caution|DO NOT USE THIS VERSION OF THE LAB. This page will no longer be updated.|'''New version here:''' https://seneca-ictoer.github.io/ULI101/A-Tutorials/tutorial3<br />'''Andrew's students please go here:''' http://wiki.littlesvr.ca/wiki/OPS145_Lab_3}}
=ADVANCED UNIX / LINUX FILE MANAGEMENT=
===Main Objectives of this Practice Tutorial===
:* Understand the difference between '''absolute''' / , '''relative''' / and '''relative-to-home''' pathnames
:* Become productive using various at issuing Linux commands with the most appropriate pathname types for Unix/Linux File Management
:* Understand the following Use '''Ambiguous Filename expansionExpansion''' ('''FNE''') Symbols: '''*''' / , '''?''' / , '''[ ]''' / , '''[! ]'''
:* Become productive using FNE for Unix/Linux File Management :* Understanding Use '''quotation symbols: Backslash \ , single quotes ' ' , double quotes " " :* Understand the purpose of quoting ' treat special characters for File Management and as just '''text''' when issuing Linux commands.
:* Understand the quotation symbols: '''Backslash \''' , '''single quotes ' '''' and '''double quotes " "'''
<br><br>
===Tutorial Reference Material===
|colspan="1" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;"|Course Notes<br>
|colspan="2" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;padding-left:15px;"|Pathname Type / Filename Expansion / Quoting Reference<br>
|colspan="1" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;padding-left:15px;"|YouTube Videos<br>
|- valign="top" style="padding-left:15px;"
|colspan="1" width="22%" |Course '''Slides:'''<ul><li>Week 3 Lecture 1 Notes:<ulbr> [https://wiki.cdot.senecacollege.ca/uli101/slides/ULI101-3.1.pdf PDF] | [https://wiki.cdot.senecacollege.ca/uli101/slides/ULI101-3.1.pptx PPTX]</li><li>Week 3 Lecture 2 Notes:<br>[https://ictwiki.cdot.senecacollege.ca/~uli101/notesslides/Week02ULI101-3.2.pdf PDF] | [https://ictwiki.cdot.senecacollege.ca/~uli101/notesslides/Week02ULI101-3.2.pptx PPTX]<br></li></ul>
| style="padding-left:15px;" |'''Pathname Types/ Filename Expansion:'''
* [https://www.cyberciti.biz/faq/understanding-absolute-pathnames/ Absolute]<br>
* [httphttps://www.ugradoreilly.math.ubc.cacom/library/view/web-design-in/Flat0596009879/relpathch04s02s02.html Relative]<br>
* [https://stackoverflow.com/questions/24048533/unix-simple-what-is-a-relative-to-home-pathname Relative-to-home]<br>
* [https://docstore.mik.ua/orelly/linux/run/ch04_08.htm#:~:text=Another%20way%20to%20save%20time,is%20sometimes%20called%20%22globbing.%22 Filename Expansion Symbols* Asterisk '''*''' , Question '''?''' ,<br>Character Class '''[ ]''' and '''[! ]'''<br>
| style="padding-left:15px;"|Quotation Symbols'''Quoting Special Characters:'''
* [http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_03.html Backslash '''\''' , Single ''' ' ' ''' , Double '''" "''']<br>
'''Linux Commands:'''
* [https://man7.org/linux/man-pages/man1/echo.1.html echo]
|colspan="1" style="padding-left:15px;" width="30%"|'''Instructional Videos:'''<ul><li>[https://www.youtube.com/watch?v=ephId3mYu9o Pathname Types]</li> <li>[https://youtu.be/5FQnehwzwSM Filename Expansion Examples]</li>
<li>[https://youtu.be/3quKLqUFGHo Relative, Absolute, and Relative-to-Home Filepaths]</li>
<li>[https://www.youtube.com/watch?v=mzgfE6-ZtUY Quoting Special Characters]</li></ul>
|}
= KEY CONCEPTS =
===Pathname Types===
'''For Example:'''<br><span style="font-family:courier">/home/userid/uli101/cars.txt</span> ('''absolute pathname''')<br><span style="font-family:courier">samples/cars.txt</span> ('''relative pathname''')<br><span style="font-family:courier">~/cars.txt</span> ('''relative-to-home pathname''')
====Absolute Pathnames====
<table align="right"><tr><td>[[Image:absolute-path-2.png|thumb|right|250px|Directories The directory in red display displays the FULL path from the '''root''' directory to the '''bin''' directory (i.e. the absolute pathname: '''/bin'''.]]</td><td>[[Image:absolute-path-1.png|thumb|right|250px|Directories in red display the FULL path from the '''root''' directory to the '''examples''' directory (i.e. the absolute pathname: '''/home/useridyour-user-id/uli101/examples'''.]]</td></tr></table>
An '''absolute pathname''' is a path to the a file or directory always <br>'''beginning from the root directory (i.e. / )'''.
This type of pathname is referred to as '''absolute''' because the pathname always begins from the '''root directory, ''', regardless the location or your current directory'''. In other words, this type of pathname requires that you always provide the '''FULL''' pathname starting with the root directory.
:* Useful if you do not know your current directory location
:* Easier to understand Understand the FULL layout location of pathnamefile within the filesystem.
''ExampleExamples:''<br><span style="color:blue;font-family:courier;">mkdir ls /bin<br>ls /home/useridyour-user-id/uli101/examples</span> will create the '''uli101''' directory in the home directory of the user called: userid. This command is using an absolute pathname.
<br><br>
<table align="right"><tr><td>[[Image:relative-pathname-1.png|thumb|right|250px|Directories in red display the path from the current directory location (which is '''xyz100''') to the '''bin''' directory (i.e. the relative pathname: '''../../../bin'''.]]</td><td>[[Image:relative-pathname-2.png|thumb|right|250px|Directories in red display the path from the current directory location (which is '''uli101''') to the '''examples''' directory (i.e. the relative pathname: '''uli101/examples''' or ./uli101/examples]]</td></tr></table>
A '''relative pathname ''' is a path to a file or directory that begins from your '''current''' directory. This is called relative because it is used to locate a specific file <u>relative </u> to your current directory.
'''NOTE:''' In order to use relative pathnames, it is <u>absolutely necessary</u> that you know the '''location''' of your '''current directory'''!
''Relative Pathname Symbols:''
:'''<span style="font-size:1.5em;">.</span> ''' A period symbol "." represents the '''current ''' directory:'''<span style="font-size:1.5em;">..</span>''' Two consecutive period symbols ".." represents the '''parent ''' directory (i.e. one level up)
<br><br>
====Relative-to-home Pathnames====
<table align="right"><tr><td>[[Image:relative-to-home-1.png|thumb|right|250px|Directories in red display the path from the home directory of the current user (which is '''userid''') to the '''examples''' directory (i.e. the relative-to-home pathname: '''~/uli101/examples'''.]]</td><td>[[Image:relative-to-home-2.png|thumb|right|250px|Directories in red display the path from the current another user's home directory location (which is '''uli101''') to the their '''examplesnotes''' directory (i.e. the relative -to-home pathname: '''~jane/uli101/examplesnotes''' or ./uli101/examples]]</td></tr></table>You can specify a pathname as A '''relative-to-home by using a pathname''' begins with the tilde and slash at the start, character ( i.e.g. '''~/uli101/notes) to represent the user’s home directory.html'''<br><br>The tilde character character '''~'''' is replaced by your stores the path of the user’s home directory <br>(typically i.e. '''~ = /home/current-user-id''') <br><br>You can immediately place a username after the tilde to represent another user’s home directory(e.g. For example <span style="font-family: courier">'''~jane = /home/jane''' ''Advantages of using Relative-to-home Pathnames:''</span>)
Examples:<br><span style="color:blue;font-family:courier">ls ~/uli101/examples<br>ls ~murray.saul/uli101/notes</span>
'''NOTE:''' Deciding which '''type of pathname''' to use depends on many factors including: '''knowledge of current directory''', '''knowledge of directory structure''', <br>'''currently directory location''', and '''type of file management command''' that is being used.
<br><br>
===Filename Expansion===
''Examples:''
You issued can use a special character to indicate to the '''ls''' command Bash shell to view match all of files that end with the files contained in your current directoryextension ".txt":
<span style="font-familycolor:courierblue;>'''ls'''<br>a.txt b.txt c.txt 1.txt 2.txt 3.txt abc.txt work.txt webpage.html picture.png</span> You now want to list just text files (i.e. files with the extension ".txt").<br>One method to do this is to issue the ls command and specify each file pathname as a separate argument: <span style="font-family:courier;>'''ls a.txt b.txt c.txt 1.txt 2.txt 3.txt abc.txt work*.txt'''<br>
a.txt b.txt c.txt 1.txt 2.txt 3.txt abc.txt work.txt</span>
<span table cellpadding="5"><tr><th style="fontborder-bottom: 1px solid black;text-familyalign:courierleft;">Filename<br>Expansion<br>Symbol</th><th valign="bottom" style="border-bottom: 1px solid black;text-align:left;">Purpose</th></tr><tr><td>'''ls *'''</td><td>Asterisk (*) to represent '''0 or more characters'''</td></tr><tr><td>'''?'''</td><td>Question mark (?) to represent '''exactly one character (any character)'''</td></tr><tr><td>'''[ ]'''</td><td>Square brackets ([ ]) to represent and match for the <br>'''character enclosed within the square brackets'''.txt<br>It represents ONLY ONE character - it's like a<br>'''Question Mark (?)''' but with '''conditions or restrictions'''</td></tr><tr><td>'''[! ]'''</td><td>Square brackets containing an exclamation mark immediately after<br>the open square bracket ([! ]) to represent and match and<br>a'''OPPOSITE''' character for the character enclosed within the square brackets.txt b.txt c.txt 1.txt 2.txt 3.txt abc.txt work.txt</spantd></tr></table>
As discussed in the above section, there are some special characters that the shell uses to perform<br>an operation; for example, the filename expansion symbols: '''*''' or '''?'''
There are ''How Does this Work? '3 methods''' to make those special characters '''act only like text characters'''<br>when issuing Linux commands (Process of Globbingdisplayed in chart below)'':
<table cellpadding="5"><tr><th style="border-bottom: 1px solid black;text-align:left;">Quoting Method</th><th style="border-bottom: 1px solid black;text-align:left;">Example</th></tr><tr><td>Place the character '''\''' <u>before</u> a special character</td><td><span style="font-family:courier">'''echo \*'''</span></td></tr><tr valign="top"><td>Contain special characters within '''double-quotes'''<br>'''NOTE:''' Double quotes works for most special<br>characters, but not all special characters (such as $)<br></td><td><span style="font-family:courier">'''echo "* hello *"'''</span></td></tr><tr valign="top"><td>Contain Special character within single '''quotes'''<br>(Quotes out ALL special characters)</td><td><span style="font-family:courier">'''echo '* hello *''''</span></td></tr></table>
[[Image:dir12.png|right|350px|thumb|]]
The best way to learn about pathname different types of file pathnames is to issue many use them while issuing<br>Linux file management commands using each type (absolute, relative, relative-to-home) and see which ones pathnames (or combinationof pathnames) is the '''<u>most </u> efficient '''<br>(i.e. requiring the '''least number of keystrokes''').
'''Perform the Following Steps:'''
# '''Login''' to your matrix account.<br><br># Issue a command to '''confirm''' you are located in your home directory.<br><br>Let's create the following directory structure under your home directory by issuing the mkdir command using only absolute pathnames.<br><br># Issue the following Linux command to create the directory structure displayed to the right using '''absolute pathnames''':<br><br>'''NOTE:''' The command you issue below will be VERY LONG... just keep Just continue typing and let the text continue of separate lines. When using these absolute pathnames, start each one from the root directory (/) and Remeber to replace the text "youruserid" with your actual login Seneca-id.<br><br># Issue the following Linux command to create the directory structure displayed to the right using '''absolute pathnames''':<br><br><span style="color:blue;font-weight:bold;font-family:courier;">mkdir -p /home/youruserid/tutorial3/practice/commands /home/youruserid/tutorial3/practice/examples /home/youruserid/tutorial3/notes/lesson1 /home/youruserid/tutorial3/notes/lesson2</span><br><br># Issue the following Linux command to confirm that you properly created the directory structure:<br><span style="color:blue;font-weight:bold;font-family:courier;">tree /home/youruserid/tutorial3</span><br><br>You should notice that using absolute pathnames with this Linux command '''requires a lot of typing'''.<br>Let's '''remove ''' this directory structure, and issue the same command using a ''relative-to-home '' pathnameinstead.<br><br># Issue To remove this directory structure, issue the following Linux command (enter "'''y'''" at each prompt to remove ALL contents):<br><span style="color:blue;font-weight:bold;font-family:courier;">rm -ri /home/youruserid/tutorial3</span><br><br># Issue a command tree command as you did in '''step #4''' to confirm that the tutorial3 directory (and its contents) no longer exist. You should know how to do thisstructure has been removed.<br><br>Let's recreate # Issue the following Linux command to create the same directory structure, but use a using relative-to-home pathname. pathnames:<br><br>'''NOTE:''' You usually generate the ~ character by Holding down '''SHIFT''' and press the button <br>to the <u>left </u> of the number '''1''' above the text on your keyboard.<br><br># Issue the following Linux command to create the same directory structure using relative-to-home pathnames:<br><br><span style="color:blue;font-weight:bold;font-family:courier;">mkdir -p ~/tutorial3/practice/commands ~/tutorial3/practice/examples ~/tutorial3/notes/lesson1 ~/tutorial3/notes/lesson2</span><br><br>Did this command require less typing than the previous command using absolute pathnames?<br><br># Issue the '''tree''' command to confirm the directory structure was properly created.<br><br>Let's remove the '''tutorial3 ''' directory and its contents and issue the mkdir same command with using '''relative pathnames to create the same directory structure'''.<br><br># Issue the same command as you did in '''step 4 #5''' to remove the '''tutorial3 ''' directory and its contents safely.<br><br># Issue a Linux command to confirm you removed the '''tutorial3 ''' directory and its contents.<br><br># Issue the following Linux command to create the same directory structure using relative pathnames:<br><br><span style="color:blue;font-weight:bold;font-family:courier;">mkdir -p tutorial3/practice/commands tutorial3/practice/examples tutorial3/notes/lesson1 tutorial3/notes/lesson2</span><br><br># Issue a command to verify that the proper directory structure was created.<br><br>'''QUESTION:''' Which '''mkdir''' command (pathname type) that you performed in steps '''3''' , '''67''' , and '''911''' required the <u>LEAST </u> number of keystrokes (i.e. characters)?<br><br>
[[Image:dir13.png|right|350px|thumb|]]
:You might start to may think that issuing Linux file management commands are better using '''relative''' or <br>'''relative-to-home''' pathnames instead of '''absolute''' pathnames, but this assumption may that is not always be correcttrue.
:Since the '''current ''' directory location was your '''home''' directory, then it makes sense that using to use ''relative '' or ''relative-to-home '' pathnames are more efficient. On the other hand, what if we <u>changed </u> the location to a different directory? Then perhaps, using an absolute pathname would be preferable.
:When performing the next series of steps, refer to the '''tree diagram''' on the right. It is '''HIGHLY RECOMMENDED''' to always refer to a tree diagram when issuing Linux using different pathnames. Learning to reference a tree diagram on a '''quiz''', '''midterm''' or '''final exam''' can help to '''prevent errors and loss of marks!'''
<br>
'''Perform the Following Steps:'''
# Issue a Linux command to confirm you are located in the ''examples'' directory.<br><br>
# Remembering that we are located in the '''examples''' directory, issue the following Linux command <br>using a '''relative''' pathname to display files in the /bin directory: <span style="color:blue;font-weight:bold;font-family:courier;">ls ../../../../../bin</span><br><br># Now issue the following Linux command using an '''absolute''' pathname: <span style="color:blue;font-weight:bold;font-family:courier;">ls /bin</span><br><br>Which type of pathname would be the best to use in this situation?<br><br>'''NOTE:''' Although it would work, using Using the previous command using the '''relative-to-home ''' pathname would work, <br> but it would look weird. Try to issue the command yourself!<br><br># Let's copy the file called ls which is contained in the '''/bin''' directory to your '''home''' directory by using the '''cp''' command. <br>First, issue the following Linux command to copy the ls command from the /bin directory to your home directory using absolute pathnames: <br><span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls /home/youruserid</span><br><br># Now let's issue the previous command using just relative pathname (remember, our current directory location is '''examples'''):<br><span style="color:blue;font-weight:bold;font-family:courier;">cp ../../../../../bin/ls ../..</span><br><br>'''TIP:''' For relative pathnames that move up multiple parent directories such as these, it is HIGHLY RECOMMENDED <br>to view the tree diagram and check for the correct number of .. symbols. Students commonly make mistakes <br>and lose marks on these type of questions!<br><br>
# Let's issue the command using one absolute pathname and a relative pathname: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls ../..</span><br>What did this command do?<br><br>
# Let's issue the same command using one absolute pathname and a relative-to-home pathname: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls ~</span><br>What did this command do?<br><br>Which of the following file type combinations requires the LEAST number of keystrokes to copy the ls file to your home directory?<br><br>
# Let's copy the '''ls ''' file from the '''/bin ''' directory to your <u>current</u> directory (i.e. examples): <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls .</span><br><br># Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls ./ls.bk</span><br><br>What does this command do?<br><br>Let's run a checking script to make certain you performed the a few of the recently-issued commands correctly.<br><br># Make certain that your current directory is '''your home directory'''.<br><br># Issue the following Linux command to run a checking script: <span style="color:blue;font-weight:bold;font-family:courier;">bash /home/murray.saul/scripts~uli101/week3-check-2</span><br><br># If you encounter errors , make corrections and then re-run the checking script until you receive a congratulations message, <br>and proceed to the next INVESTIGATION.<br><br>
=INVESTIGATION 2: FILENAME EXPANSION=
You will now get practice issuing Linux file management commands using '''filename expansion symbols'''.<br>We will be using the directory structure that was created in the previous INVESTIGATION. A great way to practice filename expansion, use the '''touch''' command to create a lot of empty filenames,<br>write the '''ls''' Linux commands that use '''filename expansion''', predict the filenames that will be display,<br>and finally run the command to check your work.<br><br>
[[Image:dir12.png|right|350px|thumb|]]
:'''Perform the following steps:'''
# Issue a Linux command to move to the '''commandsexamples''' directory<br>(i.e. under ''practice'' directory as shown in diagram to the right).<br><br># Issue a Linux command to confirmed that you have moved to the ''commands'examples''' directory.<br><br># Issue a Linux the '''touch''' command to create the following empty regular text files in the ''commandsexamples'' directory:<br>(note ''upper'' and ''lowercase'' letters)<br><br>
<div style="font-family:courier;margin-left:50px;font-weight:bold;">abc.txt<br>def.text<br>hij.TxT<br>1a4.txt<br>123.TXT<br>456.txt<br>6u9.txt<br>
ab2.html<br>1234.txt<br>abcdef.txt<br>abcde.txt<br><br></div>
<ol><li value="4">Issue To verify that you properly created those files, issue the '''ls''' command to get a listing of files in your commands directory.following:<br><brspan style="color:blue;font-weight:bold;font-family:courier;">The output should look identical to the diagram displayed below~uli101/week3-check-3<br/span><br><br><br>[[Image:listing-1If you encounter errors, then make corrections (eg.png|left|650px|thumb|]]'''viewing directory contents''', '''check for correct filename syntax''',</libr><li>Before proceeding, let's run a checking script to make certain that you created these regular ''case sensitivity''', '''missing files correctly:<br>Make certain that your current directory is '''your home directory, '''.<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 investigation.<br></li><li>Issue the following Linux command to run a checking script:<brbr><span style="color:blue;font-weight:bold;font-family:courierred;">bash /home/murray.saul/scripts/week3-check-3'''ATTENTION''':</spanbr>Learning to '''fix your mistakes''' by issuing Linux commands may be required if you make mistakes<br>in your online tutorial. </span><br></libr><li>If you encounter errors and re-run Issue the checking script until you receive a congratulations message, and continue '''ls''' command to get a listing of files in this sectionyour ''examples'' directory.<br><br>'''NOTE: To become comfortable with using filename expansion symbols, an excellent practice method is The output should look identical to the diagram displayed below.<br>You can refer to this listing to create multiple see all files (so you have already done that), look at the Linux command using filename expansion symbols and view the listing of files in the current directory that match and then write down on a paper the expected output of commands can then predict the output from Linux commands that use filename expansion symbols. You can then run the command to see the results in order to check your work.'''<<br><br>Let's try this for each of the situation below[[Image:<listing-1.png|left|650px|thumb|]]<br><br><br><br></li><li>Issue 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>Issue 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 '''issue the command ''' to check your answer.<br><br></li><li>Issue 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>Issue 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>Issue 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>Issue 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>Issue 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>Issue 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>Issue What do you think the following 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>Issue 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>Write down What is the expected purpose of this command? Which files are contained in this output on paper, then issue the command to check your answer.?<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.* .</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? .</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><li/ol>Before proceeding, let's run a checking script : Proceed to make certain that you created these regular files correctly:<br>Make certain that your current directory is '''your home directory'''.<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-4</span><br><br></li><li>If you encounter errors and re-run the checking script until you receive a congratulations message, and continue in the next INVESTIGATION.<br><br></ol>
= INVESTIGATION 3: QUOTING SPECIAL CHARACTERS =
As discussed in the above investigation, there are some special characters that the shell uses to perform an operation<br>including the filename expansion symbol: '''*'''
There is a method make the shell '''ignore the purpose of special characters''' and treat as '''regular text'''.
:'''Perform the Following Steps:'''
[[Image:quotation.png|right|350px|thumb|Using quotation to make the shell '''ignore the purpose of special characters''' and treat as '''regular text'''.]]
# Issue a Linux command to confirmed that you are still in the '''commands''' directory<br>(if not, change to the ''commands'' directory and confirm).<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo hello there</span><br><br>'''NOTE:''' the '''echo''' command is used to display text onto your terminal.<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo * hello *</span><br><br>What happened? What is shown in addition to the text "hello".<br>Why do you think those filenames are also being displayed?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo \* hello \*</span><br><br>What do you notice? What does the \ character do?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo "* hello *"</span><br><br>Is there a difference between this command and the previous command?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo '* hello *'</span><br><br>Is there any difference between this command and the two previous commands?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo $USER</span><br><br>'''NOTE''': The environment variable '''USER''' contains the current user's login name.<br>The '''$''' character immediately followed by the environment variable name causes it to<br>expand to the '''value''' that the variable contains.<br><br>
# Issue the following Linux command (using single quotes): <span style="color:blue;font-weight:bold;font-family:courier;">echo '* $USER *'</span><br><br>What happened? Why is the output display like this?<br><br>
# Issue the following Linux command (using double quotes): <span style="color:blue;font-weight:bold;font-family:courier;">echo "* $USER *"</span><br><br>What happened? Why?<br><br>
# Let's use quoting special characters for a couple of other commands. Move to the '''lesson2''' directory.<br>Confirm that you are currently located in the ''lesson2'' directory.<br><br>'''NOTE:''' Although it is NOT RECOMMENDED to create a filename using a special character (remember file naming rules?),<br>we will create an empty file called "*"<br><br>
# Issue the following Linux command (using single quotes): <span style="color:blue;font-weight:bold;font-family:courier;">touch '*'</span><br><br>
# Issue the '''ls''' command. Do you now see a file called "*" in addition to the other copied files?<br><br>
# Issue the following Linux command to remove the file called "*": <span style="color:blue;font-weight:bold;font-family:courier;">rm *</span><br><br>
# Issue the '''ls''' command to view the files in your current directory. What happened?!?<br>Why is it dangerous to use special characters when creating filenames?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">cp /bin/ls .</span><br><br>
# Issue the following Linux command (using single quotes): <span style="color:blue;font-weight:bold;font-family:courier;">touch '*'</span><br><br>
# Issue the '''ls''' command to view the files in your current directory.<br><br>
# Issue the following Linux command (using single quotes): <span style="color:blue;font-weight:bold;font-family:courier;">rm '*'<br><br>
# Issue the '''ls''' command to confirm that the file called "*" has been removed in your current directory. What happened this time?<br><br>
# Complete the Review Questions sections to get additional practice.<br><br>
= LINUX PRACTICE QUESTIONS =
The purpose of this section is to obtain extra practice to help with your assignment #1, quizzes, your midterm, and your final ezamexam.
Here is a link to the MS Word Document of ALL of the questions displayed below but with extra room to answer on the document to
simulate a quiz:
https://ictwiki.cdot.senecacollege.ca/~murray.saululi101/uli101files/uli101_week3_practice.docx
Your instructor may take-up these questions during class. It is up to the student to attend classes in order to obtain the answers to the following questions. Your instructor will NOT provide these answers in any other form (eg. e-mail, etc).
When answering Linux command questions on this side or the back side of this page, refer to the following Inverted Tree diagram. The uli101 week3 directory is contained in your home directory. Assume that you just logged into your Matrix account. Directories are underlined.
[[Image:dir13week3-practice-question.png|left|300px|thumb|]]
# Write a single Linux command using relative pathnames to create the directory structure displayed in the diagram above.
# Write a single Linux command to create the empty files “.answers.txt” and “questions.txt” shown in the diagram above using absolute pathnames.
# Assuming that you remain in the “backup” directory, write a Linux command to copy the “questions.txt file” to your current directory. You are required to only use relative pathnames.
# Assuming that you remain in the “backup” directory, write a Linux command to delete the “questions.txt” file that is in your “backup” directory. Use a relative-to-home pathname.
# Assuming that you are currently located in your “backup” directory, write a Linux command to safely remove the directory “uli101” “week3” and all of its contents. Use an absolute pathname.<br>Will your command you wrote in question 8 work if you run it? (yes/no). Why?<br><br>
# Assuming you are still located in the “backup” directory. Write a Linux command using a relative-to-home pathname to remove all files that end with the extension “.txt” in the “final” directory.
# Write a Linux command using an absolute pathname to list all files that consist of just 4 consecutive characters that are contained in your home directory.
# Write a Linux command using a relative pathname to list all files that begin and end with a number.# Write a Linux command using a relative-to-home pathname to list all files that begin with a number but ends with any character other than a number.# Assuming you are in your home directory. Write a Linux command using a relative pathname to view the contents of regular files whose file names only consist of 5 consecutive numbers.<br><br># Write a Linux command to display the following message:<br>*** Hello ***<br><br>
# Write a Linux command to display the following message (including quotation marks):<br>“This is my message”<br><br>
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Author: Murray Saul
License: LGPL version 3
Link: https://www.gnu.org/licenses/lgpl.html
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