Cron: time-based Job Scheduler

Nightly Reboot. Edit crontab: sudo crontab -e Insert a line like: 0 3 * * * /sbin/shutdown -r +5 Scheduling breakdown: m h dom mon dow command minute hour dayOfMonth … Read more

SSH Keys

SSH keys are a method of identifying trusted computers without passwords.   Create RSA Key Pair: ssh-keygen -t rsa Store the Key: Enter file in which to save the key (/home/user/.ssh/id_rsa): … Read more

Ubuntu Users

List all users: cut -d: -f1 /etc/passwd Add a new user: sudo adduser new_username To remove/delete a user: sudo userdel username To delete the home directory for the deleted user account: … Read more

ubuntu /boot full

List installed kernels: sudo dpkg –list ‘linux-image*’ Remove individual kernel: sudo apt-get remove linux-image-x.xx.x-xx-generic Removed unneeded packages: sudo apt-get autoremove Update grub kernel list: sudo update-grub