Changes

=INTRODUCTION TO SHELL SCRIPTINGUSING SED & AWK UTILTIES=

:* Understand Use the process for planning prior '''sed''' command to writing '''manipulate text''' contained in a shell scriptfile.

:* Understand List and explain several '''addresses''' and '''instructions''' associated with the purpose of a she-bang line contained at the top of a shell script'''sed''' command.

:* Setting permissions for Use the '''sed''' command as a shell script and properly execute a shell script'''filter''' with Linux pipeline commands.

:* Understand and use environment and user-defined variables within Use the '''awk''' command to '''manipulate text''' contained in a shell scriptfile.

:* Understand List and explain '''comparison operators''', '''variables''' and '''actions''' associated with the purpose of control flow statements used with shell scripts'''awk''' command.

:* Use the test '''awk''' command to test various conditionsas a '''filter''' with Linux pipeline commands. :* Use the if logic statement and the for loop statement within shell scripts.<br><br>

|colspan="2" |Course Notes'''Slides''':<ul><li>Week 11 Lecture 1 Notes:<br> [[Media:ULI101-Week11.1.pdf | PDF]] | [https://ictmatrix.senecacollege.ca/~murraychris.sauljohnson/uli101ULI101/ULI101-Week11.1.pptx PPTX]</li><li>Week 11 Lecture 2 Notes:<br> [[Media:ULI101-Week10Week11.2.pdf | PDF]] | [https://ictmatrix.senecacollege.ca/~murrayjason.saulcarman/uli101slides/ULI101-Week10Week11.2.pptx PPTX]<br></li></ul> 

| style="padding-left:15px;" |Shell Scripting'''Commands:'''* [https://searchdatacenter.techtargetman7.comorg/definitionlinux/shellman-script Purpose]* [https:pages/man1/wwwsed.youtube1p.com/watch?v=cQepf9fY6cE Creating and Running a Shell Scripthtml sed]<br>Variables* [https://opensourceman7.comorg/articlelinux/19/8/what-are-environmentman-variables Environment]* [https:pages/man1/www.linuxtechiawk.com/variables-in-shell-scripting/#:~:text=User%20Defined%20Variables%3A,like%20a%20real%20computer%20program1p. User Definedhtml awk]

|colspan="1" style="padding-left:15px;" width="30%"|'''Brauer Instructional Videos:'''<ul><li>[https://www.youtube.com/watch?v=kxEP-KUhOSgnpU6S61AIko&list=PLU1b1f-2Oe90TuYfifnWulINjMv_Wr16N&index=5 Introduction to Shell Scripting14 Using the sed Utility]</li><li>[https://www.youtube.com/watch?v=XVTwbINXnk4OV3XzjDYgJo&list=PLU1b1f-2Oe90TuYfifnWulINjMv_Wr16N&index=6 13 Using Variables and Control Flow Statements in Shell Scriptingthe awk Utility]</ul>

[[Image:ipso.png|thumb|right|500px|An IPSO Diagram (INPUT, PROCESSING, STORAGE, OUTPUT) can be used to map-out and then list the sequence of steps to assist when coding your shell script.]]It is recommended to '''plan''' out on a piece of paper the purpose of the shell script.<br>You can do this by creating a simple '''IPSO''' diagram (stands for '''INPUT''', '''PROCESSING''', '''STORAGE''', '''OUTPUTUsage:''').

'''Using a Shebang LineHow it Works:'''

[[Image:shebang.png|thumb|right|200px|* The '''shebang line''' <u>must</u> appear on the '''first line''' and at the '''beginning''' of the shell script.]]If you are learning Bash scripting by reading other people’s code you might have noticed<br>that the first line sed command reads all lines in the scripts starts with the #! characters and the path input file and will be exposed to the Bash interpreter.This sequence of characters (#!) is called '''shebang''' and is used to tell the operating systemexpression<br>which interpreter to use to parse the rest of the file(i. Reference: https://linuxizee.com/post/bash-shebang/ The '''shebang line''' <u>must</u> appear on the '''first area contained within quotes) one line''' and at the '''beginning''' of the shell script,<br>otherwise, it will be treated as a regular comment and ignoredtime. '''Setting Permissions &amp; Running a Shell Script''' To run your shell script by name, you need to assign execute permissions for the user.<br>To run the shell script, you * The expression can execute it using a relative, absolute, be within single quotes or relative-to-home pathname '''Example:<br><br><span style="font-family:courier;">chmod u+x myscriptdouble quotes.bash<br>./myscript.bash<br>/home/username/myscript.bash<br>~/myscript.bash</span>''' ===Using Variables in Shell Scripts=== '''Definition''' '''Variables''' are used to '''store information''' to be referenced and manipulated in a computer program.<br>They also provide a way of labeling data with a descriptive name, so our programs can be understood<br>more clearly by the reader and ourselves.<br>'''Reference:''' https://launchschool.com/books/ruby/read/variables  '''Environment Variables''' [[Image:environment.png|thumb|right|500px|Examples of using '''Environment''' and '''User Defined''' variables.]]Shell environment variables shape the working environment whenever you are logged in Common shell. Some of these variables are displayed via Linux commands in the diagram displayed on the right-side.<br>* The expression contains an address (you can issue the pipeline command '''set | more''' to view all variablesmatch condition) Placing a dollar sign and an instruction ('''$'''operation) prior to the variable name will cause the variable to expand to the value contained in the variable.  '''User Defined Variables''' '''User-defined variables''' are variables which can be '''created by the user''' and exist in * If the session. This means that no one can access user-defined variables that have been set by another userline matches the address,<br>and when the session is closed these variables expire.<br>'''Reference:''' https://mariadbthen it will perform the instruction.com/kb/en/user-defined-variables/ Data can * Lines will display be stored and removed within a variable using an equal sign.<br>The default unless the '''read–n''' command can be option is used to prompt the user to enter data into a variable.<br>Refer to the diagram on the right-side to see how user-defined variables are assigned data.suppress default display'''Positional Parameters and Special Parameters''' [[Image:positional.png|thumb|right|220px|Examples of using '''positional''' and '''special''' parameters.]]A '''positional parameter''' is a variable within a shell program; its value is set from an argument specified on the command line that invokes the program.Positional parameters are numbered and are referred to with a preceding "'''$'''": '''$1''', '''$2''', '''$3''', and so on. The positional parameter $0 refers to either the name of shell where command was issued, or name of shell script being executed. If using '''positional parameters''' greater than '''9''', then you need to include number within braces.<br>Examples: '''echo ${10}''', '''ls ${23}''' The '''shift''' command can be used with positional parameters to shift positional parameters<br>to the left by one or more positions. There are a few ways to assign values as positional parameters:Address:*Use the '''set''' command with the values as argument after the set command:*Run a shell script containing arguments

[[Image:sed.png|right|500px|]]'''Instruction:'''*'''Action''' to take for matched line(s)*Refer to the diagram to the table on right -side for examples using positional list of some<br>'''common instructions''' and special parameters.their purpose<br><br>

===Using Control Flow Statements in Shell Scriptsthe awk Utility===

The special parameter '''$?Usage:''' Is used to determine the exit status of the previously issued Linux command.The exit status will either display a zero (representing TRUE) or a non-zero number (representing FALSE). This can be used to determined if a Linux command was correctly or incorrectly executed.

The <span style="color:blue;font-weight:bold;font-family:courier;">awk [-F] '''test''' Linux command is used to test conditions to see if they are '''TRUE''' (i.e. value '''zero''') or '''FALSE''' (i.e. value '''nonselection-criteria {action}’ file-zero''') so they can be used with control flow statements to control the sequence of a shell script.name</span>

Refer * The '''awk''' command reads all lines in the input file and will be exposed to diagrams the expression (contained within quotes) for processing.*The '''expression''' (contained in quotes) represents '''selection criteria''', and '''action''' to execute contained within braces '''{}'''* if selection criteria is matched, then action (between braces) is executed.* The '''–F''' option can be used to specify the right involving the test commanddefault '''field delimiter''' (separator) character<br>eg. '''awk –F”;”''' (would indicate a semi-colon delimited input file).<br>'''Selection Criteria'''

* You can use a regular expression, enclosed within slashes, as a pattern. For example: '''Logic Statements/pattern/'''* The ~ operator tests whether a field or variable matches a regular expression. For example: '''$1 ~ /^[0-9]/'''A * The '''logic statement!~''' is used to determine which Linux commands to be executed based<br>on the result of a condition (ioperator tests for no match.e. TRUE For example: '''$2 !~ /line/'''* You can perform both numeric and string comparisons using relational operators (zero value) or FALSE (non-zero value)). <table align="right"'''>''' , '''><tr valign="top">''' , '''<td>[[Image:logic-1.png|thumb|right|250px|Example of using the '''if, ''' logic control-flow statement.]]</td><td>[[Image:loop-1=''' , '''==''' , '''!=''' ).png|thumb|right|250px|Example * You can combine any of the patterns using the Boolean operators '''for||''' (OR) and '''&&''' looping control(AND).* You can use built-flow statementin variables (like NR or "record number" representing line number) with comparison operators.]]</tdbr></tableFor example: '''NR > There are several logic statements, but we will just concentrate on the if statement.=1 && NR <pre style="width:20%">if test condition then command(s) fi5''' </prebr> Refer to the diagram relating to logic statements on the right side for an example. '''Loop StatementsAction (execution):'''

A * Action to be executed is contained within braces '''{}'loop statement''* The ' is a series ''print''' command can be used to display text (fields).* You can use parameters which represent fields within records (lines) within the expression of steps or sequence the awk utility.* The parameter '''$0''' represents all of the fields contained in the record (line).* The parameters '''$1''', '''$2''', '''$3''' … '''$9''' represent the first, second and third to the 9th fields contained within the record. * Parameters greater than nine requires the value of statements executed repeatedly zero or more times satisfying the given condition is satisfiedparameter to be placed within braces (for example: '''${10}''','''${11}''','''${12}''', etc.)* You can use built-in '''variables''' (such as '''NR''' or "record number" representing line number)<br>Reference: https://wwweg.chegg'''{print NR,$0}''' (will print record number, then entire record).com/homework-help/definitions/loop-statement-3

<pre span style="widthcolor:20%red;">for item '''ATTENTION''': Effective '''May 9, 2022''' - this online tutorial will be required to be completed by '''Friday in list do command(s) doneweek 11 by midnight'''<br>to obtain a grade of '''2%''' towards this course</prespan><br><br>

Refer to the diagram relating to looping statements on the right side for an example. =INVESTIGATION 1: CREATING A SHELL SCRIPT= <br>In this sectioninvestigation, you will learn how to create and run a simple Bash Shell scriptmanipulate text using the '''sed''' utility.

# '''Login''' to your matrix accountand confirm you are located in your '''home''' directory.<br><br># Issue a Linux command to create a directory called '''confirmsed''' you are located in your home directory.<br><br>We want # Issue a Linux command to create a Bash Shell script <u>change</u> to welcome the user by their username. Let's first provide some useful tips ''sed''' directory and confirm that you are located in terms<br>of selecting an appropriate name for the shell script'''sed''' directory.<br><br># Issue the following linux Linux command to check if your intended shell script namedownload the data.txt file<br>is already exists ('''copy and paste''' to be run automatically from the Bash shellsave time):<br><span style="color:blue;font-weight:bold;font-family:courier;">which hellowget <nowiki>https://ict.senecacollege.ca/~murray.saul/uli101/data.txt</nowiki></span><br><br>You should notice that there is no output and therefore, this shell script name can be used# Issue the '''more''' command to quickly view the contents of the '''data.txt''' file.<br>On When finished, exit the other hand, if you wanted more command by pressing the letter <span style="color:blue;font-weight:bold;font-family:courier;">q</span>[[Image:sed-1.png|thumb|right|300px|Issuing the '''p''' instruction without using the '''-n''' option (to create a file called sed, then suppress original output) will display lines twice.]]<br><br>The '''p''' instruction with the '''which sed''' commandis used to<br>would indicate it is already being used by the shell and that '''sedprint''' (i.e. ''display' wouldn't be an appropriate shell script name to use) the contents of a text file.<br><br># Use a text editor like vi or nano to create Issue the text file called hello (eg. following Linux command:<br><span style="color:blue;font-weight:bold;font-family:courier;">vi hellosed 'p' data.txt</span><br><br>'''NOTE: You should notice that each line appears twice'''.<br><br>The reason why standard output appears twice is that the sed command<br>(without the '''-n option''')displays all lines regardless of an address used.<br><br>If you are using We will use '''pipeline commands''' to both display stdout to the nano text editor, refer screen and save to notes on text editing in files<br>for <u>confirmation</u> of running these pipeline commands when run a previous week '''checking-script''' later in the course schedulethis investigation.<br><br># Enter Issue the following two lines in your shell script, replacing "your-username" with your actual nameLinux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">clear<br>echo "Hello yoursed -n 'p' data.txt | tee sed-username"1.txt</span><br><br># Save your editing session and exit What do you notice? You should see only one line.<br><br>You can specify an '''address''' to display lines using the text editor sed utility<br>(eg. with vi: press '''ESC'line #'', then type ''':wxline #s''' followed by or range of '''ENTERline #s''').<br><br># Issue the following linux Linux pipeline command to run your shell script in your current directory:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed -n '1 p' data./hellotxt | tee sed-2.txt</span><br><br>You should notice an error indicating you don't have permissions to run see the first line of the text filedisplayed.<br>You need What other command is used to only display the first add execute permissions prior to running the shell script.line in a file?<br><br>[[Image:sed-2.png|thumb|right|500px|Using the sed command to display a '''range''' of lines.]]# Issue the following linux Linux pipeline command to add execute permissions for your shell script:<br><span style="color:blue;font-weight:bold;font-family:courier;">chmod u+x hellosed -n '2,5 p' data.txt | tee sed-3.txt</span><br><br>What is displayed? How would you modify the sed command to display the line range 10 to 50?<br><br>The '''s''' instruction is used to '''substitute''' text<br>(a similar to method was demonstrated in the vi editor in tutorial 9).<br><br># Re-run your shell scriptIssue the following Linux pipeline command: <br><span style="color:blue;font-weight:bold;font-family:courier;">sed '2,5 s/TUTORIAL/LESSON/g' data./hellotxt | tee sed-4.txt | more</span><br><br>Although your shell script should work, it is recommended What do you notice? View the original contents of lines 2 to force your shell script to run 5 in a specific shellthe '''data. This helps prevent your txt''' file<br>in another shell script encountering errors when run in to confirm that the incorrect shell (isubstitution occurred.<br><br>[[Image:sed-3.epng|thumb|right|500px|Using the sed command with the '''-q''' option to display up to a line number, then quit. syntax not recognized ]]The '''q''' instruction terminates or '''quits''' the execution of the sed utility as soon as it is read in a specific shell)particular line or matching pattern.<br><br># Edit your Issue the following Linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed '11 q' data.txt | tee sed-5.txt</span><br><br>What did you notice? How many lines were displayed<br>before the sed command exited?<br><br>You can use '''helloregular expressions''' shell script using to select lines that match a text editorpattern. In fact,<br>the sed command was one of the <u>first</u> Linux commands that used regular expression.<br><br># Insert the following line at The rules remain the same for using regular expressions as demonstrated in '''beginningtutorial 9''' of <br>except the regular expression must be contained within '''firstforward slashes''' line of your hello file:<br>(eg. <span style="font-family:courier;font-weight:bold;">#!/binregexp/bash</span>).<br><br>This is referred to as a she[[Image:sed-bang line4. It forces png|thumb|right|400px|Using the script to be run in sed command using regular expressions with '''anchors'''.]]# Issue the Bash Shellfollowing Linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed -n '/^The/ p' data. When your Bash Shell script finishes execution, txt | tee sed-6.txt</span><br><br>What do you are returned to your current shell that you are using (which in our case in Matrix, is still the Bash shell).notice?<br><br># Save your editing changes and exit your text editorIssue the following Linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed -n '/d$/ p' data.txt | tee sed-7.txt</span><br><br># It is What do you notice?<br><br>The '''sed''' utility can also be used as a good idea '''filter''' to rename your shell script to include an extension to indicate manipulate text that <br>was generated from Linux commands.<br><br>[[Image:sed-5.png|thumb|right|400px|Using the file is a Bash Shell script filesed command with '''pipeline''' commands. ]]# Issue the following linux Linux pipeline command to rename your shell script file:<br><span style="color:blue;font-weight:bold;font-family:courier;">mv hello hellowho | sed -n '/^[a-m]/ p' | tee sed-8.bashtxt | more</span><br><br>What did you notice?<br><br># Run your renamed shell script by issuingIssue the following Linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">.ls | sed -n '/txt$/hellop' | tee sed-9.bashtxt</span><br><br>What did you notice?<br><br> # Issue the following to run a checking script:<br><span style="color:blue;font-weight:bold;font-family:In the next investigationcourier;">~uli101/week11-check-1</span><br><br>If you encounter errors, you will learn to create make corrections and '''re-run shell scripts that''' the checking script<br>use variablesuntil you receive a congratulations message, positional and special parametersthen you can proceed.<br><br> =INVESTIGATION 2: USING VARIABLES IN SHELL SCRIPTS =

:In this sectionthe next investigation, you will learn how to use variables, positional and special parameters to assist you in creating adaptable shell scriptsmanipulate text using the '''awk''' utility.<br><br>

# Use Change to your '''home''' directory and issue a text editor command to edit the shell script '''confirm'''<br>you are located in your ''home'' directory.<br><br># Issue a Linux command to create a directory called '''hello.bashawk'''<br><br># Add the following line Issue a Linux command to <u>change</u> to the bottom of '''awk''' directory and confirm you are located in the '''awk''' directory.<br><br>Let's download a database filethat contains information regarding classic cars.<br><br># Issue the following linux command ('''copy and paste''' to save time):<br><span style="color:blue;font-weight:bold;font-family:courier;">echo wget <nowiki>https://ict.senecacollege.ca/~murray.saul/uli101/cars.txt</nowiki></span><br><br># Issue the '''cat''' command to quickly view the contents of the '''cars.txt''' file.<br><br>The "The current shell you are using '''print'''" action (command) isthe <u>default</u> action of awk to print<br>all selected lines that match a '''pattern'''.<br><br>This '''action''' (contained in braces) can provide more options<br>such as printing '''specific fields''' of selected lines (or records) from a database.<br><br>[[Image: $SHELLawk-1.png|thumb|right|400px|Using the awk command to display matches of the pattern '''ford'''.]]# Issue the following linux command all to display all lines (i.e. records) in the '''cars.txt''' database that matches the pattern (or "make") called '''ford''':<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '/ford/ {print}' cars.txt</span><br><br># Save your editing changes We will use '''pipeline commands''' to both display stdout to the screen and exit your text editorsave to files for <u>confirmation</u> of running these pipeline commands when run a '''checking-script''' later in this investigation.<br><br># Issue the following linux pipeline command all to change to display records<br>in the '''cars.txt''' database that contain the c-shell pattern (a different shell than the default Bashi.e. make)'''ford''':<br><span style="color:blue;font-weight:bold;font-family:courier;">cshawk '/ford/' cars.txt | tee awk-1.txt</span><br><br>What do you notice? You should notice ALL lines displayed <u>without</u> using '''search criteria'''.<br><br>You can use ''builtin'' '''variables''' with the '''print''' command for further processing.<br>We will discuss the following variables in this tutorial:<br><br>[[Image:awk-2.png|thumb|right|400px|Using the awk command to print search results by '''field number'''.]]'''$0''' - Current record (entire line)<br>'''$1''' - First field in record<br>'''$n''' - nth field in record<br>'''NR''' - Record Number (order in database)<br> '''NF''' - Number of fields in current record<br><br>For a listing of more variables, please consult your course notes.<br><br># Issue the following linux pipeline command confirm you are to display the '''model''', '''year''', '''quantity''' and price<br>in the c'''cars.txt''' database for makes of '''chevy''':<br><span style="color:blue;font-shellweight:bold;font-family:courier;">awk '/chevy/ {print $2,$3,$4,$5}' cars.txt | tee awk-2.txt</span><br><br>Notice that a '''space''' is the delimiter for the fields that appear as standard output.<br><br>The '''tilde character''' '''~''' is used to search for a pattern or display standard output for a particular field.<br><br># Issue the following linux pipeline command to display all '''plymouths''' ('''plym''')<br>by '''model name''', '''price''' and '''quantity''':<br><span style="color:blue;font-weight:bold;font-family:courier;">echo awk '$1 ~ /plym/ {print $2,$3,$SHELL4,$5}' cars.txt | tee awk-3.txt</span><br><br>You should see the output of can also use '''comparison operators''' to specify conditions for processing with matched patterns<br>when using the awk command that you . Since they are located in used WITHIN the cawk expression,<br>they are not confused with redirection symbols<br><br>[[Image:awk-shell3.png|thumb|right|400px|Using the awk command to display results based on '''comparison operators'''.]]'''<''' &nbsp;&nbsp;&nbsp;&nbsp;Less than<br>'''<=''' &nbsp;&nbsp;Less than or equal<br>'''>''' &nbsp;&nbsp;&nbsp;&nbsp;Greater than<br>'''>=''' &nbsp;&nbsp;Greater than or equal<br>'''==''' &nbsp;&nbsp;Equal<br>'''!=''' &nbsp;&nbsp;&nbsp;Not equal<br><br># Run your helloIssue the following linux pipeline command to display display the '''car make''', '''model''', '''quantity''' and '''price''' of all vehicles whose '''prices are less than $5,000''':<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '$5 < 5000 {print $1,$2,$4,$5}' cars.bash shell scripttxt | tee awk-4. txt</span><br><br>What shell does the shell script indicate is runningdo you notice?<br><br>This is because # Issue the following linux pipeline command to display display '''price''',<br>'''quantity''', '''model''' and '''car make''' of vehicles whose '''prices are less than $5,000''':<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '$5 < 5000 {print $5,$4,$2,$1}' cars.txt | tee awk-5.txt</span><br><br># Issue the shebang line indicating following linux pipeline command to run display the '''car make''',<br>'''year''' and '''quantity''' of cars that '''begin''' with the shell script in '''letter 'f'''':<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '$1 ~ /^f/ {print $1,$2,$4}' cars.txt | tee awk-6.txt</span><br><br>[[Image:awk-4.png|thumb|right|400px|Using the Bash shell although you ran this script within awk command to display combined search results based on '''compound operators'''.]]Combined pattern searches can be made<br>by using '''compound operator''' symbols:<br><br>'''&&''' &nbsp;&nbsp;&nbsp;&nbsp;(and)<br>'''||''' &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(or)<br><br># Issue the cfollowing linux pipeline command to list all '''fords'''<br>whose '''price is greater than $10,000''':<br><span style="color:blue;font-shellweight:bold;font-family:courier;">awk '$1 ~ /ford/ && $5 > 10000 {print $0}' cars.txt | tee awk-7.txt</span><br><br># Enter Issue the following linux command ('''copy and paste''' to return to your Bash shellsave time): <br><span style="color:blue;font-weight:bold;font-family:courier;">exitwget <nowiki>https://ict.senecacollege.ca/~murray.saul/uli101/cars2.txt</nowiki></span><br><br># Use a text editor Issue the '''cat''' command to edit quickly view the contents of the shell script called '''hellocars2.bashtxt'''file.<br><br># Add Issue the following lines linux pipeline command to display the bottom '''year'''<br>and '''quantity''' of cars that '''begin''' with the file'''letter 'f'''' for the '''cars2.txt''' database:<br><span style="color:blue;font-weight:bold;font-family:courier;">echo "awk '$1 ~ /^f/ {print $2,$4}' cars2.txt | tee awk-8.txt</span><br><br>What did you notice?<br><br>The current username problem isthat the '''cars2.txt''' database separates each field by a semi-colon (''';''') <u>instead</u> of '''TAB'''.<br>Therefore, it does not recognize the second and fourth fields.<br><br>You need to issue awk with the -F option to indicate that this file's fields are separated (delimited) by a semi-colorn.<br><br># Issue the following linux pipeline command to display the '''year'''<br>and '''quantity''' of cars that '''begin''' with the '''letter 'f'''' for the '''cars2.txt''' database: $USER"<br>echo <span style="The current directory location iscolor:blue;font-weight:bold;font-family: $PWDcourier;"<br>echo awk -F";"The current user's home directory is: $HOME1 ~ /^f/ {print $2,$4}' cars2.txt | tee awk-9.txt</span><br><br>What did you notice this time?<br><br># Save your editing changes Issue the following to run a checking script:<br><span style="color:blue;font-weight:bold;font-family:courier;">~uli101/week11-check-2</span><br><br>If you encounter errors, make corrections and exit your text editor'''re-run''' the checking script until you<br>receive a congratulations message, then you can proceed.<br><br>

In the next investigationThe purpose of this section is to obtain '''extra practice''' to help with '''quizzes''', you will ..your '''midterm''', and your '''final exam'''.

=INVESTIGATION 3Here is a link to the MS Word Document of ALL of the questions displayed below but with extra room to answer on the document tosimulate a quiz: USING CONTROL FLOW STATEMENTS IN SHELL SCRIPTS =

In this section, you will learn how to https://ict.senecacollege.ca/~murray.saul/uli101/uli101_week11_practice.docx

'''Perform the Following StepsReview Questions:'''

The purpose of this section <pre>Line one.This is to obtain '''extra practice''' to help with '''quizzes''', your '''midterm''', and your '''final exam'''the second line.This is the third.Here This is a link to the MS Word Document of ALL of the questions displayed below but with extra room to answer on the document toline four.Five.Line six followsFollowed by 7Now line 8and line nineFinally, line 10simulate a quiz:</pre>

Your instructor may take-up these questions during class. It is up to Write the student to attend classes in order to obtain results of each of the answers to following Linux commands for the following questions. Your instructor will NOT provide these answers in any other form (eg. eabove-mail, etc).mentioned file:

# <span style="font-family:courier;font-weight:bold">sed -n '3,6 p'~murray.saul/uli101/stuff.txt</span><br><br># <span style="font-family:courier;font-weight:bold">sed 'Review Questions4 q' ~murray.saul/uli101/stuff.txt</span><br><br># <span style="font-family:courier;font-weight:bold">sed '/the/ d'~murray.saul/uli101/stuff.txt</span><br><br># <span style="font-family:courier;font-weight:bold">sed 's/line/NUMBER/g'~murray.saul/uli101/stuff.txt</span>

'''PART APart B: WRITE BASH SHELL SCRIPT CODEWriting Linux Commands Using the sed Utility'''

'''Write a single Linux command to perform the answer to specified tasks for each question below the question in of the space providedfollowing questions.'''

# Write a Bash shell script that clears Linux sed command to display only lines 5 to 9 for the screen and displays the text Hello World on the screenfile: '''~murray.saul/uli101/stuff.<br><br><br><br><br>What permissions are required to run this Bash shell script?<br><br><br>What are the different ways that you can run this Bash shell script from the command line?<br>txt'''<br><br># Write a Bash shell script that clears Linux sed command to display only lines the screen, prompts begin the user pattern “and” for their '''full name''' and then prompts the user for their file: '''age~murray.saul/uli101/stuff.txt''',<br>then clears the screen again and welcomes the user by their name and tells them their age.<br> <br><br><br><br><br><br><br>What comments would you add # Write a Linux sed command to display only lines that end with a digit for the above script’s contents to properly document this Bash shell script to be understood<br>for those users that would read file: '''~murray.saul/uli101/ edit this Bash shell script’s contents?<br> stuff.txt'''<br><br># Write a Bash shell script Linux sed command to save lines that will first set match the pattern “line” (upper or lowercase) for the value of a variable called file: '''number~murray.saul/uli101/stuff.txt''' and save results (overwriting previous contents) to : '''23''' and make this variable '''read-only~/results.txt'''.<br>Then the script will clear the screen and prompt the user to enter a value for that variable called number to another value.<br>Have the script display the value of the variable called number to prove that it is a read-only variable.<br><br><br><br><br>When you ran this Bash shell script, did you encounter an error message?<br>How would you run this Bash shell script, so the error message was NOT displayed?<br><br><br># Write a Bash shell script that will clear the screen and then display all arguments that were entered after your Bash shell script when it was run. Also have the Bash shell script display the number of arguments that were entered after your Bash shell script.<br><br><br><br><br><br><br><br>

'''Write Part C: Writing Linux Commands Using the expected output from running each of the following Bash shell scripts You can assume that these Bash shell script files have execute permissions. Show your work.awk Utility'''

:Note the contents from the following tab-delimited file called '''Walkthru #1:~murray.saul/uli101/stuff.txt''':(this file pathname exists for checking your work)

#!/usr/bin/bashLine one.word1=”counter”This is the second line.word2=”clockwise”This is the third.echo “The combined word This is: $word2$word1”line four.Five.Line six followsFollowed by 7Now line 8and line nineFinally, line 10

Write a single Linux command to perform the specified tasks for each of the following questions.  # Write a Linux awk command to display all records for the file: '''~/cars''' whose fifth field is greater than 10000.<br><br># Write a Linux awk command to display the first and fourth fields for the file:'''Walkthru ~/cars''' whose fifth field begins with a number.<br><br>#2Write a Linux awk command to display the second and third fields for the file:'''~/cars''' for records that match the pattern “chevy”.<br><br># Write a Linux awk command to display the first and second fields for all the records contained in the file: '''~/cars'''<br><br>