Raspberry Pi

Configure

Here some pointers on configuring your device.

Configure tool

sudo raspi-config

Bash shell timout

Automatic logout of a user bash session after a period of inactivity.

sudo nano /etc/profile

...
# set a 25 min (1500 sec) timeout policy for bash shell 
TMOUT=1500
readonly TMOUT
export TMOUT
...

HDMI mode in config.txt

At boot the file 'config.txt' is used to apply several non-default settings. This file is on your FAT boot partition which is usually available as /boot after the Pi is up and running.

More info on config.txt:

• https://www.raspberrypi.org/documentation/configuration/config-txt/README.md

If you don't provide specific settings for 'hdmi_group' and 'hdmi_mode' a mode will be negotiated with the de HDMI display device. If this doesn't work out for you, you can change config.txt to get what you want, here are some examples:

sudo nano /boot/config.txt

...
#VGA
hdmi_group=1
hdmi_mode=1

#1024x768
hdmi_group=2
hdmi_mode=16

#720p 60Hz 	
hdmi_group=1
hdmi_mode=4

#1080p 60Hz
hdmi_group=1
hdmi_mode=16
...

More info on HDMI:

• https://www.raspberrypi.org/documentation/configuration/config-txt/video.md

SSH Remote control

You can use remote shell to control your Raspberry Pi without directly connected mouse, keyboard and screen.

ssh pi@192.168.1.2

Ssh copy local file to remote machine

scp /path/to/local/file.zip pi@192.168.1.2:/home/pi/Downloads/file.zip

And back:

scp pi@192.168.1.2:/home/pi/Downloads/file.zip /path/to/local/file.zip

Nautilus ssh access, in the addressbar type:

ssh://pi@192.168.1.2

Ssh root access is not allowed by default but could be convenient for use with Nautilus Note: better set this back to 'no' when you are done

sudo nano /etc/ssh/sshd_config

PermitRootLogin yes

You can now access the machine as root with Nautilus, in the addressbar type:

ssh://root@192.168.1.2/

Allow ssh scripting without a password request, based on keys

You want the script to execute without it stopping to ask for a password.

• http://www.linuxproblem.org/art_9.html

Root session:

sudo -i

Generate keys, accept defaults:

ssh-keygen -t rsa

Create dir on remote:

ssh pi@192.168.1.2 mkdir -p .ssh

Add pub key to pi@192.168.1.2 authorized_keys:

cat .ssh/id_rsa.pub | ssh pi@192.168.1.2 'cat >> .ssh/authorized_keys'

Should work now without password:

ssh pi@192.168.1.2

Maybe needed, for some versions of ssh

cat .ssh/id_rsa.pub | ssh pi@192.168.1.2 'cat >> .ssh/authorized_keys2'
ssh pi@192.168.1.2 chmod 700 .ssh
ssh pi@192.168.1.2 chmod 640 .ssh/authorized_keys2

Require pi to enter password when sudo

By default the Raspbian pi user can sudo without the need to re-enter the password. If you don't like that make this change.

• https://raspberrypi.stackexchange.com/questions/57887/disable-sudo-for-user-pi-or-require-root-password

ssh pi@192.168.1.2
sudo nano /etc/sudoers.d/010_pi-nopasswd

Change it from:

pi ALL=(ALL) NOPASSWD: ALL

to

pi ALL=(ALL) ALL

VNC

For mouse and screen people.

• https://www.raspberrypi.org/documentation/remote-access/vnc/

Database MySql /MariaDB remote access

See MySQL remote

Performance tuning

Memory

• https://serverfault.com/questions/201075/what-tips-do-you-have-for-speeding-up-performance-of-a-mediawiki-installation

Raspberry Pi lowered GPU memory from 64 to 32 MB

Run headless (without desktop) by default

Start config tool:

sudo raspi-config

Configure these options:

1. Boot options - Desktop: select text console login
2. Interfacing - VNC server: enable

If you now want to start the desktop:

1. Set up a VNC client session to the machine
2. Login via the text console
3. Start the desktop:

startx

Bring Wifi down if Ethernet cable is connected

Create file:

nano /home/pi/Scripts/wlan0downifeth0.sh

#!/bin/bash
if [[ -n $( ip a show eth0 up ) ]] ; then
  echo "wlan0 down"
  ifconfig wlan0 down
fi

Make executable:

chmod +x /home/pi/Scripts/wlan0downifeth0.sh

Modify crontab, check every hour:

sudo nano /etc/crontab

#every hh:45 if eth0 up then wlan0 down
45 * * * * root /home/pi/Scripts/wlan0downifeth0.sh

To bring wifi up:

sudo ifconfig wlan0 up

To check the wifi status (returns nothing if down):

ip a show wlan0 up

Remove software packages

Slim down Raspberry Pi default installation by removing some packages

• https://blog.samat.org/2015/02/05/slimming-an-existing-raspbian-install/

Remove packages with:

apt-get -y remove --purge <package1> <package2>

Education related packages:

idle idle3
python3-pygame python-pygame python-tk python3-tk python-serial python3-serial python-picamera 
python3-picamera python3-pygame python-pygame python-tk python3-tk python3-numpy python3-pifacecommon 
python3-pifacedigitalio python3-pifacedigital-scratch-handler python-debian-reference-en python-pifacedigitalio
dillo x2x scratch nuscratch timidity smartsim pistore sonic-pi pifacecommon oracle-java8-jdk wolfram-engine	
minecraft-pi python-minecraftpi penguinspuzzle

Remove other packages:

sudo apt-get purge libreoffice*
sudo apt-get purge chromium-browser
sudo apt-get purge cups-common 
sudo apt-get purge xpdf gcalculator
#replacment browser (if you want)
sudo apt-get install midori

Remove unreferenced packages:

apt-get -y autoremove

Remove all packages marked 'rc':

dpkg --list |grep "^rc" | cut -d " " -f 3 | xargs dpkg --purge

See also

• Raspberry Pi LAMP stack
• MediaWiki
• Raspberry Pi SOGo Groupware
• Raspberry Pi GPIO Shutdown Button
• Raspberry Pi system clone and/or resize
• Raspberry Pi monitor