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→INVESTIGATION 3: USING START-UP FILES
=INVESTIGATION 3: USING START-UP FILES =
In this section, you will learn how to '''customize ''' your '''Bash Linux shell environment''' by creating and testing a startup start-up file.
'''Perform the Following Steps:'''
# Use the '''more''' command to view the contents of the start-up file called '''/etc/profile''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">more /etc/profile</span>)<br><br>This file contains the '''default settings ''' when you open your Bourne shell (eg. if issuing the command '''sh''').<br><br># Use the '''more''' command to view the contents of the start-up file called '''/etc/bashrc''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">more /etc/bashrc</span>)<br><br>This file contains the '''default settings ''' when you '''open your Bash shell ''' (eg. if issuing the command '''bash''').<br><br>Since we are using the Bash shell by default, let's create a customized Bash start-up file.<br>This startup file is located in your '''home ''' directory using the name "'''.bashrc'''"<br><br>
# Let's move your .bashrc file to prevent accidental overwrite. Issue the following linux command:<br><span style="color:blue;font-weight:bold;font-family:courier;">mv ~/.bashrc ~.bashrc.bk</span><br><br>If you experience an error message "''No such file or directory''", just ignore since there is no startup file to backup.<br><br>
# Use a text editor like vi or nano to create the text file called '''~/.bashrc''' (eg. <span style="color:blue;font-weight:bold;font-family:courier;">vi ~/.bashrc</span>)<br><br>If you are using the nano text editor, refer to notes on text editing in a previous week in the course schedule.<br><br>
# Enter the following lines in your shell script (the symbol "<span style="font-family:courier;font-weight:bold;">[</span>" is the open square bracket symbol):<br><span style="font-family:courier;">clear<br>echo -e -n "\e[0;34m"<br>echo "Last Time Logged in (for security):"<br>echo<br>lastlog -u $USER<br>echo<br>echo -e -n "\e[m"</span><br><br>
# Save your editing session and exit the text editor (eg. with vi: press '''ESC''', then type ''':wx''' followed by '''ENTER''').<br><br>
# You can test run the startup file without exiting and re-entering your Bash shell environment.<br>Issue the following:<br><span style="color:blue;font-weight:bold;font-family:courier;">. ~/.bashrc</span><br><br>What do you notice?<br><br>
# '''Login''' again to your matrix account.<br><br>Did you start-up file customize your Bash shell environment with colours?<br><br>
# Issue the following linux command to restore your previous settings for your bashrc startup file:<br><span style="color:blue;font-weight:bold;font-family:courier;">mv ~/.bashrc.bk ~/.bashrc</span><br><br>If you experience an error message "''No such file or directory''", just ignore.<br><br>
# After you complete the Review Questions sections to get additional practice, then work on your '''online assignment 3,'''<br>'''sections 4 to 6''' labelled: '''More Scripting (add)''', '''Yet More Scripting (oldfiles)''', and '''sed And awk'''<br><br>
