nano /usr/local/bin/monitoring.sh - opens monitoring.sh source code

sudo cat /var/log/sudo/sudo.log - displays the content of sudo.log, the file that saves logs everytime a sudo command is used

sudo ufw status - displays the current firewall status (rules i.e allowed/denied PORTS)

sudo ufw allow - allow a new PORT

sudo ufw delete allow - delete the firewall rule that allows PORT

sudo useradd novouser - create a new user

sudo addgroup newgroup - create a new group

sudo adduser newuser user42 - add newuser to a group

getent group user42/sudo - displays the users currently in the group

sudo deluser newuser user42 - removes newuser from a group

lsblk - displays the disk partitions

sudo crontab -e - check if the monitoring script is scheduled on crontab

sudo crontab -r - remove the current crontab tasks

sudo crontab -l - show the current crontab tasks

sudo nano /etc/pam.d/common-password - password policy

sudo service ssh status - show the status of ssh

sudo visudo - sudo restrictions

nano /etc/hostname - change the hostname

hostname -I - get VM's ip

ssh -p 4242 @<VM's ip> - connect Host terminal with the VM

sha1sum <machine_name>.vdi - generate the signature