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→INVESTIGATION 3: OTHER COMMANDS THAT USE REGULAR EXPRESSIONS
# Issue the following Linux command to download another data file called '''large-file.txt''':<br><span style="color:blue;font-weight:bold;font-family:courier;">wget <nowiki>https://ict.senecacollege.ca/~murray.saul/uli101/large-file.txt</nowiki></span><br><br>
# View the contents of the '''large-file.txt''' file using the '''more''' command and quickly view the contents of this file.<br><br>
# Issue the following Linux command to view the contents of the '''textfile1large-file.txt''':<br><span style="color:blue;font-weight:bold;font-family:courier;">more textfile1large-file.txt</span><br><br>
#We want to search for a pattern '''uli101''' within this text file.<br>Type the following regular expression and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">/uli101</span><br><br>What did you notice?<br><br>
#Search for the next occurrence of the pattern '''uli101''' by '''re-typing'''<br>the following regular expression and pressing ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">/uli101</span><br><br>you should now see the '''second occurrence''' of this pattern within the text file.<br><br>
# Press the letter <span style="color:blue;font-weight:bold;font-family:courier;">q</span> to exit the '''more''' command.<br><br>
# Try the same search techniques with the '''less''' command.<br><br>Does it work the same for the ''less'' command as it did for the ''more'' command?<br><br>
#Let's learn how to perform a simple '''search and replace''' within the '''vi''' utility by using regular expressions.<br>Issue the following linux command to edit the '''textfile1large-file.txt''' file:<br><span style="color:blue;font-weight:bold;font-family:courier;">vi textfile1large-file.txt</span><br><br>Let's first perform a simple search within this text file.<br><br>
# Type the following and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">/uli101</span><br><br>You should move to the '''first occurrence''' of the pattern: '''uli101'''.<br><br>Let's search for the '''uli101''' pattern, but replace it in capitals (i.e '''ULI101''').<br><br>In vi, in order to perform and command, you need to go into last line mode, and then issue a command to apply to the entire text file, followed by a regular expression to search for and a regular expression to replace (i.e. '''/search/replace/''').<br><br>
# Type the following and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">:%s/uli101/ULI101</span><br><br>You should have noticed that the first occurrence of uli101 has been changed to ULI101.<br><br>
