Editing RPi

=== Setup as output ===

 echo &quot;23&quot; &gt; /sys/class/gpio/export
 echo &quot;out&quot; &gt; /sys/class/gpio/gpio23/direction

 echo &quot;1&quot; &gt; /sys/class/gpio/gpio23/value
 echo &quot;0&quot; &gt; /sys/class/gpio/gpio23/value

=== Setup as input ===

 echo &quot;23&quot; &gt; /sys/class/gpio/export
 echo &quot;in&quot; &gt; /sys/class/gpio/gpio23/direction

 cat /sys/class/gpio/gpio23/value

 echo &quot;23&quot; &gt; /sys/class/gpio/unexport

Or:

 gpio -g mode 23 out
 gpio -g write 23 1
 gpio -g write 23 0

=== Network interface with multiple IP's ===

/etc/network/interfaces

 auto lo
 
 iface lo inet loopback
 auto eth0
 iface eth0 inet dhcp
 
 auto eth0:0
 iface eth0:0 inet static 
       address 192.168.1.42 
       netmask 255.255.255.0
 
 allow-hotplug wlan0
 iface wlan0 inet manual
 wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
 iface default inet dhcp

=== Crontab ===

 @reboot /home/pi/projects/orca/orca.sh > orca.log 2>&1