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→INVESTIGATION 3: ALIASES / COMMAND HISTORY
= INVESTIGATION 3: ALIASES / COMMAND HISTORY =
=INVESTIGATION 3: ALIASES / COMMAND HISTORY=
<br>
In this investigation, you will learn how to '''manage aliases''' and '''Linux command history''' on your Matrix account.
'''Perform the Following Steps:'''
# Make certain that you are logged into your Matrix account.<br><br>[[Image:alias-1.png|thumb|right|400px|Issuing the '''alias''' command (<u>without</u> arguments) will display a list of existing aliases on your Unix / Linux system.]]
# Issue a Linux command to confirm that you are located in your '''home''' directory.<br><br>
# Issue the following Linux command: <span style="color:blue;font-family:courier;font-weight:bold">alias | more</span><br><br>Observe those <u>existing</u> aliases that have previously been declared. Take a few moments to run those aliases to see what happens.<br><br>
# Issue the following to create an alias: <span style="color:blue;font-family:courier;font-weight:bold">alias lal='ls -al'</span><br><br>
# Issue the following alias: <span style="color:blue;font-family:courier;font-weight:bold">lal</span><br><br>What do you notice?<br><br>
# Issue the following to create another alias (lowercase l and h):<br><span style="color:blue;font-family:courier;font-weight:bold">alias lh='ls --human-readable --size -1 -S --classify'</span><br><br>
# Issue the following command to confirm that this newly-created alias is stored in memory:<br><br><span style="color:blue;font-family:courier;font-weight:bold">alias | grep "lh"</span><br><br>
# Issue the following alias: <span style="color:blue;font-family:courier;font-weight:bold">lh</span> <br><br>What do you think this command does?<br><br>
# '''Logout''' of your Matrix account and then '''login''' to your Matrix account.<br><br>
# Reissue the '''lal''' alias. What happened?<br><br>
# Reissue the '''lh''' alias. What happened?<br><br>
# Issue the '''alias | grep lh''' command without any arguments to see if it is stored in memory.<br><br>
# Reissue the command to create the '''lh''' alias in '''step #6'''.<br><br>
# Run the '''lh''' alias to confirm that it is properly set in memory.<br><br>
# Issue the following Linux command to edit your ~/.bashrc startup file:<br><span style="color:blue;font-family:courier;font-weight:bold">nano ~/.bashrc</span><br><br>
# Add the following line at the '''bottom''' of this file:<br><span style="font-family:courier;font-weight:bold;>alias lh='ls --human-readable --size -1 -S --classify'</span><br><br>
# Save your editing changes and exit your text editor.<br><br>
# '''Logout''' of your Matrix account, then '''login''' to your Matrix account.<br><br>
# Reissue the '''lh''' alias. What happened?<br><br>
# Issue the following Linux command: <span style="font-family:courier;font-weight:bold;>unalias lh</span><br><br>
# Run the '''lh''' alias to see what happens.<br><br>What happenned?<br><br>
# '''Logout''' of your Matrix account, then '''login''' to your Matrix account.<br><br>
# Reissue the '''lh''' alias. What happened? Why?<br><br>
# Reissue the '''lal''' alias. Why '''didn't''' this alias work?<br><br>The checking script below is designed to act as a '''filter''' with a '''pipeline command'''.<br>This will allow to check if your '''lh''' alias exists when it is checked in this program.<br><br>
# Issue the following Linux pipeline command:<br><span style="color:blue;font-weight:bold;font-family:courier;">alias | ~uli101/week8-check-3</span><br><br>If you encounter errors, then view the feedback to make corrections, and then re-run the checking script.<br>If you receive a congratulation message that there are no errors, then proceed with this tutorial.<br><br>We will complete this investigation by learning to execute p'''reviously issued commands''' by using '''command history'''.<br><br>
# Issue the following Linux command: <span style="color:blue;font-family:courier;font-weight:bold">history | grep "lh"</span><br><br>What do you notice?<br><br>
# Type an exclamation mark '''!''' followed by the number by one of those commands<br>listed in the '''history list''' and press <span style="color:blue;font-family:courier;font-weight:bold">ENTER</span><br><br>What happened?<br><br>
# Type the following: <span style="color:blue;font-family:courier;font-weight:bold">!unalias</span> and press <span style="color:blue;font-family:courier;font-weight:bold">ENTER</span><br><br>What happened?<br><br>
# Issue the following Linux command: <span style="color:blue;font-family:courier;font-weight:bold">history | grep "lh"</span><br><br>What happened?<br><br>
# After you complete the Review Questions sections to get additional practice, then work on your<br>'''online assignment 2''' and complete '''section4''' labelled: '''Linking files and directories'''.<br><br>
= LINUX PRACTICE QUESTIONS =