1. /etc/debian_version

2. hostnamectl set-hostname <NAME>

   • hostnamectl = Control the system hostname
     • Can be used to change the system hostname and related settings.
   • set-hostname <NAME> = Set the system hostname to <NAME>

3. /etc/hostname

4. who -b (—boot)

   • -b = time of last system boot
   • who = show who is logged in

5. sudo service ssh status or sudo systemctl status ssh

   • Before you have to install SSH Server
     1. sudo apt-get install openssh-server to download SSH Server
     2. Enable the SSH Service with sudo systemctl enable ssh
     3. Start the SSH Service with sudo systemctl start ssh

6. sudo service ssh restart

   • (there is also start, stop, reload, status)

7. ps aux | grep -m 1 “/usr/sbin/sshd”

   • ps - report a snapshot of the current processes
   • The aux shortcut:
     • ps aux displays the most amount of information a user usually needs to understand the current state of their systems’s running processes
       • USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND

8. ~/.ssh/authorized_keys

   • if there is not the file, you can always make it.
     • ~/.ssh/known_hosts was my first guess, but there are only known hosts as the name says.
   • The authorized_keys file in SSH specifies the SSH keys that can be used for logging into the user account for which the file is configured.

9. w or who

   • w = show who is logged on and what they are doing.
   • who = show who is logged in

10. sudo fdisk -l

    • fdisk = manipulate disk partition table
    • -l → -list = List the partition tables for the specified devices

11. df -h

    • df = report file system disk space usage
    • -h → —human-readable = prints sizes in powers of 1024 (KB → MB)

12. sudo du -h -d 1 /var

    • du = estimate file space usage
    • -d → —max-depth=1

13. top = display Linux processes

    • The top program provides a dynamic real-time view of a running system.
    • It can display system summary information as well as a list of processes or threads currently being managed by the Linux kernel.

14. Run the tail -f /var/log/syslog command in background

    • sudo tail -f /var/log/syslog & should be the right answer, but it’s only working in termanal but not in file.
    • Also tried set -m
      • Job control is enabled (see Job Control). All processes run in a separate process group. When a background job completes, the shell prints a line containing its exit status
    • Use the jobs utility to display the status of all stopped and background jobs in the current shell session:
      • jobs -l
    • To bring a background process to the foreground, use the fg command.

15. sudo killall -v tail

    • killall → kill processes by name
    • -v → —verbose

<aside> 💡 https://phoenixnap.com/kb/how-to-kill-a-process-in-linux

</aside>

1. Answer is cron

<aside> 💡 https://www.makeuseof.com/tag/linux-task-scheduling-crontab-explained/#:~:text=Cron is a system service,which cron scans every minute.

</aside>

1. ssh username@remote_host -p [port]
   • Port forwarding in VirtualBox
   • Port forwarding in Parallels Desktop
   • By default, when you create a VM in VirtualBox, network adapter 1 is set to NAT. This will give the VM an IP address of 10.0.2.15/24  and a default route of 10.0.2.2  (which should be your host).
2. pkill ssh
   • pkill → Signal process by name.
     • Kill all processes witch match ‘ssh’