How to use Unix on your Raspberry PI?

This will be a useful (growing) collection of Unix / Raspbian commands to use with your Raspberry PI.

• get the current frequency of the RPi CPU:
  /opt/vc/bin/vcgencmd get_config arm_freq

• measure the temperature of the RPi CPU:
  /opt/vc/bin/vcgencmd measure_temp
  

• get the current firmware version of your RPi:
  /opt/vc/bin/vcgencmd version

• find the MAC address of your RPi:
  cat /sys/class/net/eht0/address

• show all mounts:
  df -h

• show all installed packages:
  dpkg –get-selections
  find a specific package:
  dpkg –get-selections | grep <package name>

• list all files in a directory (last modified files last):
  ls -lrt

• check for distro upgrades for your RPi:
  sudo apt-get dist-upgrade

• remove an (apt-get) application from your RPi:
  sudo apt-get –purge remove <app name> && sudo apt-get autoremove –purge

• update your system software and remove orphans:
  sudo apt-get update && sudo apt-get upgrade && sudo apt-get autoremove –purge

• switch to ‘super user‘ terminal window (means you don’t have to use the ‘sudo’ prefix in front of all the following commands)
  sudo -i

• synchronize the date and time of your RPi:
  sudo dpkg-reconfigure tzdata

• find the IP-address of your RPi:
  sudo ifconfig

• list all loaded drivers:
  sudo lsmod

• list all connected USB devices
  sudo lsusb

• edit the Raspberry PI boot configuration file:
  sudo nano /boot/config.txt

• change the system configuration of your RPi:
  sudo raspi-config

• reboot your RPi:
  sudo reboot

• update the firmware of your RPi (note: git has to be installed)
  sudo rpi-update

• list the most active system processes (quit by pressing ‘q’)
  top