Linux System Change Logger Script

The report explains the creation of a change logger script in Ubuntu OS for monitoring and managing user activity on the system. It includes the shell script used, design considerations, and extensive test results. The script uses pre-installed command line tools and stores output in an HTML file.

LINUX SYSTEM CHANGE LOGGER SCRIPT
Computer Systems and Networks
Name of the Student
Name of the University
Author’s Note

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LINUX SYSTEM CHANGE LOGGER SCRIPT
Table of Contents
Introduction................................................................................................................................2
Specification...............................................................................................................................2
Design Consideration.................................................................................................................2
Extensive test result and exemplary log and screen output........................................................3
Conclusion..................................................................................................................................9
Bibliography.............................................................................................................................10

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LINUX SYSTEM CHANGE LOGGER SCRIPT
Introduction
The report is prepared for creation of a change logger script created in ubuntu OS and
management of the regular activity of the user using the system. For the development of the
shell script the details of the system is extracted using different shell command and the output
is stored in an HTML file that would help the administrator to monitor the status of the
system. The pre-installed command line tools are used for the creation of the shell script and
the output is stored in a temporary log file for the management of the changes in the logs and
identify the changes in made in the current system.
Specification
The shell script is created using the nano editor and it is named as
“mySysMonitor.sh”, and proper permission is added to the shell script for running it.
Administrative permission is needed for running the shell script and thus “chmod +x
mySysMonitor.sh” command is used for providing appropriate permission and running the
shell script. “sudo ./mySysMonitor.sh”, command is used for running the shell script as root
user and generate the output in a HTML file.
Design Consideration
The shell script is designed using separate command for getting each of the
information necessary for the development of the change logger script. The main function of
the script is to monitor the current computer system and the activity of the user for creating a
log with the key information. The script is named as “mySysMonitor.sh” which automatically
and regularly writes the information in log file named “mySysMonitor.log”. The output of the
shell script is stored in the html file and it uses the “mySysMonitor.log” as a temporary file
for storing the result of the command executed in the shell script. Since the contents of the
file is copied in a temporary file and “tail -f” command is used for comparing the changes in

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LINUX SYSTEM CHANGE LOGGER SCRIPT
the log file and identification of the changes made in the current system. For constructing the
shell script the the following commands are used such as:
printf "At %s: \n" "$(date)" // displays the data and time of the system
ps // displays the current processes running on the system
who // finds the users logged into the system
lsusb // finds the usb devices plugged in with the system
df -h /boot|awk '{print $5 " "$6}' // used for displaying the overall disk usage
df -h /home|sed -n '2p' |awk '{print $5 " "$6}' // lists the home directory of the user
df -h // lists the other key directories of the system
ip link show // displays the network interface used for connecting with the internet
ping -c 1 google.com &> /dev/null && echo -e "Internet: Connected" || echo -e
"Internet: Disconnected"; // used for finding the connection is active or disconnected
(uptime | awk '{print $3,$4}' | cut -f1 -d,) // used for finding the system uptime
Extensive test result and exemplary log and screen output
The shell script prepared for management of the change log is given below:
#! /bin/bash
#Author : - Student
#Date : - 29 November, 2018
#Check if the script is executed as ROOT. The script must be run from a root user for
maintaining proper directory structure:
if [ $EUID != 0 ]

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LINUX SYSTEM CHANGE LOGGER SCRIPT
then
echo "Run the script as root for viewing all the details! Better run with sudo."
exit 1
fi
#Declaring variables
#set -x
Number_of_Process=`ps -ef | wc -l`
Currently_logged_in_users=`who`
Plugged_in_Devices=`lsusb`
Root_size=`df -h /dev/sda1 | tail -1 | awk '{print$2}'`
Disk_usage=`df -h /boot|awk '{print $5 " "$6}'`
Users_home_directory=`df -h /home|sed -n '2p' |awk '{print $5 " "$6}'`
ip_add=`ip link show | grep "inet addr" | head -2 | tail -1 | awk {'print$2'} | cut -f2 -d:
ping -c 1 google.com &> /dev/null && echo -e "Internet: Connected" || echo -e "Internet:
Disconnected";`
root_fs_pc=`df -h /dev/sda1 | tail -1 | awk '{print$5}'`
upt=`uptime | awk {'print$3'} | cut -f1 -d','`
#load_avg=`uptime | cut -f5 -d':'`
ram_usage=`free -m | head -2 | tail -1 | awk {'print$3'}`
ram_total=`free -m | head -2 | tail -1 | awk {'print$2'}`

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LINUX SYSTEM CHANGE LOGGER SCRIPT
inode=`df -i / | head -2 | tail -1 | awk {'print$5'}`
#Creating a directory if it doesn't exist to store reports first, for easy maintenance.
if [ ! -d ${HOME}/system_reports ]
then
mkdir ${HOME}/system_reports
fi
html="${HOME}/system_reports/System-Health-Report-`hostname`-`date +%y%m%d`-
`date +%H%M`.html"
email_add="[e-mail]"
for i in `ls /home`; do sudo du -sh /home/$i/* | sort -nr | grep G; done >
/tmp/mySysMonitor.log
#Generating HTML file
echo "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">" >> $html
echo "<html>" >> $html
echo "<link rel="stylesheet" href="https://unpkg.com/purecss@0.6.2/build/pure-min.css">"
>> $html
echo "<body>" >> $html
echo "<fieldset>" >> $html
echo "<center>" >> $html
echo "<h2>Linux System Change Logger Script" >> $html

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LINUX SYSTEM CHANGE LOGGER SCRIPT
echo "<h3><legend>Script authored by Student</legend></h3>" >> $html
echo "</center>" >> $html
echo "</fieldset>" >> $html
echo "<br>" >> $html
echo "<center>" >> $html
echo "<h2>System Details : </h2>" >> $html
echo "<table class="pure-table">" >> $html
echo "<thead>" >> $html
echo "<tr>" >> $html
echo "<th>Number_of_Process</th>" >> $html
echo "<th>Currently_logged_in_users</th>" >> $html
echo "<th>Plugged_in_Devices</th>" >> $html
echo "<th>Uptime</th>" >> $html
echo "</tr>" >> $html
echo "</thead>" >> $html
echo "<tbody>" >> $html
echo "<tr>" >> $html
echo "<td>$Number_of_Process</td>" >> $html
echo "<td>$Currently_logged_in_users</td>" >> $html
echo "<td>$Plugged_in_Devices</td>" >> $html

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LINUX SYSTEM CHANGE LOGGER SCRIPT
echo "<td>$upt</td>" >> $html
echo "</tr>" >> $html
echo "</tbody>" >> $html
echo "</table>" >> $html
echo "<h2>Resources Utilization : </h2>" >> $html
echo "<br>" >> $html
echo "<table class="pure-table">" >> $html
echo "<thead>" >> $html
echo "<tr>" >> $html
echo "<th>Overall Disk Usage</th>" >> $html
echo "<th>The user's home directory</th>" >> $html
echo "<th>Other key directories</th>" >> $html
echo "<th>Network Interface and their states</th>" >> $html
echo "<th>Used RAM(in MB)</th>" >> $html
echo "<th>Total RAM(in MB)</th>" >> $html
echo "<th>iNode Status</th>" >> $html
echo "</tr>" >> $html
echo "</thead>" >> $html
echo "<tbody>" >> $html
echo "<tr>" >> $html

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LINUX SYSTEM CHANGE LOGGER SCRIPT
echo "<td><center>$$Root_size</center></td>" >> $html
echo "<td><center>$root_fs_pc</center></td>" >> $html
echo "<td><center>$Users_home_directory</center></td>" >> $html
echo "<td><center>$ip_add</center></td>" >> $html
echo "<td><center>$ram_usage</center></td>" >> $html
echo "<td><center>$ram_total</center></td>" >> $html
echo "<td><center>$inode</center></td>" >> $html
echo "</tr>" >> $html
echo "</tbody>" >> $html
echo "</table>" >> $html
while read size name;
do
echo "<td>$size</td>" >> $html
echo "<td>$name</td>" >> $html
echo "</tr>" >> $html
echo "</tbody>" >> $html
done < /mySysMonitor.log
echo "</table>" >> $html
echo "</body>" >> $html
echo "</html>" >> $html

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LINUX SYSTEM CHANGE LOGGER SCRIPT
echo "Report has been generated in ${HOME}/mySysMonitor with file-name = $html.
Report has also been sent to $email_add."
#Sending Email to the user
cat $html | mail -s "`hostname` - mySysMonitor" -a "MIME-Version: 1.0" -a "Content-Type:
text/html" -a "From: user <[e-mail]>" $email_add
Conclusion
The creation of the shell script helps in reducing the effort of the network engineer for
monitoring and management of the activity of the user. The shell script can be executed for
getting all the information about the current system by using a single command and the user
does not need to use individual command for analysing each of the activity. Apart form the
advantage it also have some disadvantage that is the speed of execution is slower when the
shell script is compared with the different programming language that can eb used
alternatively for monitoring the activity of the current user and management of the changes
made in the current system.

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LINUX SYSTEM CHANGE LOGGER SCRIPT
Bibliography
Banfield, J., Germaine, N. and Gerard, M., 2016. Ubuntu Linux: Learn administration,
networking, and development skills with the# 1 Linux distribution!.
Brash, R. and Naik, G., 2018. Bash Cookbook: Leverage Bash scripting to automate daily
tasks and improve productivity. Packt Publishing Ltd.
Cook, J., 2017. Interactive Programming. In Docker for Data Science (pp. 49-70). Apress,
Berkeley, CA.
Domínguez, A.I.D., Díaz, W.M.F. and Gordon, S.S., 2018. Enterprise file synchronization
and sharing services for educational environments in case of disaster. Facultad de
Ingeniería, 27(47), p.3.
Flynt, C., Lakshman, S. and Tushar, S., 2017. Linux Shell Scripting Cookbook. Packt
Publishing Ltd.
Jang, M. and Orsaria, A., 2016. RHCSA/RHCE Red Hat Linux Certification Study Guide
(Exams EX200 & EX300). McGraw-Hill Education Group.
Lee, M.L., Aliagas, I., Feng, J.A., Gabriel, T., O’donnell, T.J., Sellers, B.D., Wiswedel, B.
and Gobbi, A., 2017. chemalot and chemalot_knime: Command line programs as workflow
tools for drug discovery. Journal of cheminformatics, 9(1), p.38.
Lin, X.V., Wang, C., Zettlemoyer, L. and Ernst, M.D., 2018. NL2Bash: A Corpus and
Semantic Parser for Natural Language Interface to the Linux Operating System. arXiv
preprint arXiv:1802.08979.
Mishra, D. and Khandelwal, G., 2018. Command-Line Tools in Linux for Handling Large
Data Files. In Bioinformatics: Sequences, Structures, Phylogeny (pp. 375-392). Springer,
Singapore.

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Mysore, A. and Guo, P.J., 2017, October. Torta: Generating Mixed-Media GUI and
Command-Line App Tutorials Using Operating-System-Wide Activity Tracing.
In Proceedings of the 30th Annual ACM Symposium on User Interface Software and
Technology (pp. 703-714). ACM.
Ponyared, P., Ponsawat, J., Tongsima, S., Seresangtakul, P., Akkasaeng, C. and
Tantisuwichwong, N., 2016. ESAP plus: a web-based server for EST-SSR marker
development. BMC genomics, 17(13), p.1035.
Rybczyński, M., Stefanek, G., Broniowski, W. and Bożek, P., 2014. GLISSANDO 2:
GLauber Initial-State Simulation AND mOre…, ver. 2. Computer Physics Communications,
185(6), pp.1759-1772.
Shen, Z., 2015. A Gentler Introduction to Unix.
Stevens, W.R. and Rago, S.A., 2013. Advanced programming in the UNIX environment.
Addison-Wesley.
Taylor, D. and Perry, B., 2016. Wicked Cool Shell Scripts: 101 Scripts for Linux, OS X, and
UNIX Systems. No Starch Press.
Wang, B., Lu, K. and Chang, P., 2016, August. Design and implementation of Linux firewall
based on the frame of Netfilter/IPtable. In Computer Science & Education (ICCSE), 2016
11th International Conference on (pp. 949-953). IEEE.