Challenge_09

1. Create a cron job for the currently logged in user that writes the current date and time to a file every 3 minutes.
Sol.
crontab -e
choosing vim
crontab -l
Accessing insert mode
Inserting -: */3 * * * * date >> ~/date.txt


2. Create a cron job that runs as root and fully upgrades the system every Sunday and 5:10AM
Sol.
su
crontab -l
10 5 * * 0 apt iupdate && apt full-upgrade -y


3. Run a backup script -:
   Every minute
   Everyday at 4,6 & 10 AM
   On weekdays between 9AM & 5AM once per hour
   Every three days at 4AM and 9PM at the 10th minute
   Once a year on 1st January, midnight
Sol.
crontab -e
crontab -l
* * * * * /root/backup.sh
* 4,6,10 * * * /root/backup.sh
* 9-17 * * 1-5 /root/backup.sh
10 4,21 */3 * * /root/backup.sh
@yearly /root/backup.sh


4. Identify the partition where the root file system (/) is mounted.
   Create a directory on the Desktop and mount that partition there as well in read mode.
   Undo the changes from read only to read and write modes.
   Unmount it if it is not being used
   Unmount it if it is being used
Sol.
df -h
mkdir Desktop/new_dir
sudo mount -o ro /dev/sda5 ~/Desktop/new_dir
sudo mount -o rw,remount /dev/sda5 ~/Desktop/new_dir
sudo unmount ~/Desktop/new_dir
sudo unmount -l ~/Desktop/new_dir


5. Consider an iso file and mount it on the Desktop
Sol.
mkdir  ~/Desktop/iso
sudo mount new.iso ~/Desktop/iso -o loop


6. How coes systemd starts in a linux environment.
Sol.
System powers up.
Bootloader (grub) loads the kernel.
Kernel logs an initial RAM that logs an system drive and looks for the root file system
Once kernel is setup, it begins the systemd initialization system
Systemd starts with process id, 1, as the first process, tghen takes over and continues to mount the host's file system & starts the services.


7. Install the nginx web server.
   Check that it’s running.
   Set the server NOT to start automatically when the computer boots up.
Sol.
sudo apt update && sudo apt install nginx
systemctl status nginx
sudo systemctl disable nginx
sudo systemctl is-enabled nginx