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Tutorial11: Sed & Awk Utilities

14 bytes added, 17 March
# 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 following linux command to download the data.txt file<br>('''copy and paste''' to save time):<br><span style="color:blue;font-weight:bold;font-family:courier;">wget <nowiki></nowiki></span><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 print or display<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>You should notice that each line appears '''twice'''.<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 the following linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">sed -n 'p' data.txt | tee sed-1.txt</span><br><br>What do you notice? You should see only one line.<br><br>You can specify an address (''line #'', '''line #s''' or range of '''line #s''') when using the sed utility.<br><br>

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