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