Changes

# Issue a Linux command to create a directory called '''sed'''<br><br>

# Issue a Linux command to <u>change</u> to the '''sed''' directory and confirm that you are located in the '''sed''' directory.<br><br>

# Issue the '''more''' command to quickly view the contents of the '''data.txt''' file.<br>When finished, exit the 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 suppress original output) will display lines twice.]]<br><br>The '''p''' instruction with the '''sed''' command is used to<br>'''print''' (i.e. ''display'') the contents of a text file.<br><br>

# Issue the following Linux command:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed '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>We will use '''pipeline commands''' to both display stdout to the screen and save to files<br>for <u>confirmation</u> of running these pipeline commands when run a '''checking-script''' later in this investigation.<br><br>

# Issue a Linux command to create a directory called '''awk'''<br><br>

# Issue a Linux command to <u>change</u> to the '''awk''' directory and confirm you are located in the '''awk''' directory.<br><br>Let's download a database file that contains information regarding classic cars.<br><br>

# Issue the '''cat''' command to quickly view the contents of the '''cars.txt''' file.<br><br>The "'''print'''" action (command) is the <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:awk-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>We will use '''pipeline commands''' to both display stdout to the screen and save 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 to display the '''car make''',<br>'''year''' and '''quantity''' of cars that '''begin''' with the '''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 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 following linux pipeline command to list all '''fords'''<br>whose '''price is greater than $10,000''':<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '$1 ~ /ford/ && $5 > 10000 {print $0}' cars.txt | tee awk-7.txt</span><br><br>

# Issue the '''cat''' command to quickly view the contents of the '''cars2.txt''' file.<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:<br><span style="color:blue;font-weight:bold;font-family:courier;">awk '$1 ~ /^f/ {print $2,$4}' cars2.txt | tee awk-8.txt</span><br><br>What did you notice?<br><br>The problem is that 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>