Turn 3.5mm Jack on Raspberry Pi Running LineageOS 16

You will need an Android Terminal. You can turn on the default one in the developer settings. Need to turn on developer mode?

You will also need to enable root which can also be done in the Developer settings

Open up the terminal app and run

su
rpi3-audio-jack.sh

More info here

https://konstakang.com/devices/rpi3/LineageOS16.0/

Installing LineageOS on Raspberry Pi B+

Download LineageOS

Download the unofficial LineageOS 16 build from the following page

https://konstakang.com/devices/rpi3/LineageOS16.0/

Unzip

Unzip the file with

unzip ~/Downloads/lineage-16.0-20200207-UNOFFICIAL-KonstaKANG-rpi3.zip

Write to SD Card

Either use the instructions on the following link to write it to the SD card

https://www.raspberrypi.org/documentation/installation/installing-images/windows.md

Or use DD

WARNING! Make sure “/dev/mmcblk0” is the correct SD Card. Refer to here if you need to locate the path for the SD Card.

sudo dd if=~/Downloads/lineage-16.0-20200207-UNOFFICIAL-KonstaKANG-rpi3.img of=/dev/mmcblk0 bs=1M status=progress

Plug you SD Card into your Pi and boot it up.

Raspberry Pi – Ping IP Address and Toggle LED

The following script is for monitoring if an IP address is reachable or not. If it becomes unavailable the script will turn on a LED that is plugged into one of the GPIO pins of the Raspberry Pi. View pinout here

Script

#!/bin/bash
# Script to ping ip address and turn on LED on if device is unreachable.
                                                                                                                                                                                                 nPin="18"  # Change if GPIO pin is different                                                                                                     
ledPin="gpio${nPin}"                                                                                                                                                                                                                            toPing="8.8.8.8"  # Change to address you want to ping

echo "${nPin}" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/${ledPin}/direction

if ( fping -r1 $toPing | grep -v alive ); then
         echo "Internet unreachable"
         # Turn on LED
         echo "1" > /sys/class/gpio/${ledPin}/value
 else
         # Turn off LED 
         echo "0" > /sys/class/gpio/${ledPin}/value
 fi

Save script as ping_led.sh and make it executable.

chmod +x ping_led.sh

and run the script.

sh ping_led.sh

Run script in crontab

You can setup the script to run every minute using a crontab

crontab -e

Add the following line

*/1 * * * * /home/pi/ping_led.sh

Should now execute the script every minute and not need any human interaction.

Install Slackcat on Raspberry Pi (Raspbian)

Slackcat allows you to send Slack messages from the Linux command line.

Update pi

sudo apt-get update

Install Ruby and other components

sudo apt-get install ruby1.9.1 ruby ruby-dev rubygems

Install Slackcat

sudo gem install slackcat

Use Slackcat.  You will need to generate an API Key from Slacks website.

echo "Hello World" | slackcat -k API-KEY -p --channels=#CHANNEL_NAME

Examples :
Send to Channel

echo "Hello World" | slackcat -k xoxp-94827839414-94819543146-441447827184-h7dt2hg2h8ggs7d24ce638edrw9q8def -p --channels=#General

Send Direct Message

echo "Hello World" | slackcat -k xoxp-94827839414-94819543146-441447827184-h7dt2hg2h8ggs7d24ce638edrw9q8def -p --users=#General

 

Cannot open mailbox /var/mail/pi: Permission denied

This is on a Raspberry Pi, but should be the same on any Linux distro.

Error :

pi@raspberrypi:~ $ mail
Cannot open mailbox /var/mail/pi: Permission denied
No mail for pi
pi@raspberrypi:~ $ 

Fix :

sudo touch /var/mail/$USER
sudo chown $USER:mail /var/mail/$USER
sudo chmod 660 /var/mail/$USER

You can replace “$USER” if you need to run the commands for a different account.
Example:

sudo touch /var/mail/pi
sudo chown pi:mail /var/mail/pi
sudo chmod 660 /var/mail/pi

How to Set a Static IP Address on a Raspberry Pi

The examples given here are for modifying the wlan0 interface.  Replace wlan0 with the interface you are configuring. i.e. (eth0,wlan1)

Method 1

This was the typical way to add a static IP address to a Pi, if you have issues with this, then try Method 2.

sudo vi /etc/network/interfaces

In the file it is pretty easy to see which lines control which interface, find the lines that control wlan0 (or the interface your configuring) and change/add to look like below.

iface wlan0 inet static
address 192.168.42.109
netmask 255.255.255.0
gateway 192.168.42.1

Save the file, reboot, and the Pi should come up with the new static IP.

Method 2

It looks like on the newer versions of Raspbian, the above method does not work anymore, so now you have to edit the following file

sudo vi /etc/dhcpcd.conf

and add the following lines.

interface wlan0
static ip_address=192.168.42.109/24
static routers=192.168.42.1
static domain_name_servers=192.168.42.1

If you just need to assign a static IP address, to the device, because it is going to be setup as a hotspot or something, you can get away with the following.

interface wlan0
static ip_address=192.168.42.1/24

If you run into issues with it not assigning the address, check the /etc/network/interfaces file and make sure that the line that starts with “iface wlan0” says manual at the end and not static.  If it says “iface wlan0 inet static”, change it to “iface wlan0 inet manual”

Control LED from Command Line – Raspberry Pi

Replace “4” with the GPIO pin your using.

echo "4" > /sys/class/gpio/export

Setup the direction.  If it was a button or switch we would change “out” to “in”.

echo "out" > /sys/class/gpio/gpio4/direction

Turn the LED on.

echo "1" > /sys/class/gpio/gpio4/value

Turn the LED off.

echo "0" > /sys/class/gpio/gpio4/value

1 = on and 0 = off.

 

How to View Installed Programs in linux

Debian Based Distros

The below command should work for Debain, Ubuntu, and the Raspberry Pi Raspbian.

dpkg --get-selections

 

RPM Based Distros

The following works on Fedora, CentOS, ReHat.

rpm -qa

 

The above commands return all of the packages installed on a system.  If you want to look for a specific program or package you can use grep to filter the results.

rpm -qa | grep program

or

dpkg --get-selections | grep program

How to Install CraftBukkit Minecraft Server on Raspberry Pi

First we need to Install Java.

sudo apt-get install openjdk-7-jre

Next lets create a CraftBukkit directory to store all the files.

mkdir ~/mc-bukkit
cd ~/mc-bukkit

And lets download CraftBukkit.

wget "http://dl.bukkit.org/downloads/craftbukkit/get/02389_1.6.4-R2.0/craftbukkit.jar" -O "craftbukkit.jar"

Now lets create a script that we can use to start the Server.

sudo vi /etc/init.d/mcstart.sh

Copy and paste the following text.

#! /bin/sh
# /etc/init.d/mcserver

### BEGIN INIT INFO
# Minecraft CraftBukkit Start script
### END INIT INFO

case "$1" in
  start)
    echo "Starting mcserver"
    MCDIR=$("/home/pi/craftbukkit")
    cd "$MCDIR"
    java -Xmx512M -jar craftbukkit.jar -o true &
;;
  stop)
    echo "Stopping mcserver"
    kill `pgrep mcserver`
    ;;
  *)
    echo "Usage: /etc/init.d/mcserver {start|stop}"
    exit 1
    ;;
esac
exit 0

Now lets make the file executable.

chmod +x mcstart.sh

And launch

sudo /etc/init.d/mcstart.sh

The first lunch will take a long time so be patient.

If you want to start CraftBukkit when your Pi boots up then run the following command.

sudo /etc/init.d/mcstart.sh start