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→INVESTIGATION 3: QUOTING SPECIAL CHARACTERS
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo "* hello *"</span><br><br>Is there a difference between this command and the previous command?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo '* hello *'</span><br><br>Is there any difference between this command and the two previous commands?<br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">echo $USER</span><br><br>'''NOTE''': '''USER''' is an environment variable that stores the current user's login name. <br>The '''$''' character immediately followed by the environment variable name causes it to expand to the value that the variable contains. Therefore the echo command displays the current login name of the user.<br><br>
# Issue the following Linux command (using single quotes): <span style="color:blue;font-weight:bold;font-family:courier;">echo '$USER'</span><br><br>What happened? Why is the output display like this?<br><br>
# Issue the following Linux command (using double quotes): <span style="color:blue;font-weight:bold;font-family:courier;">echo "$USER"</span><br><br>What happened? Why?<br><br>
