Raspberry Pi: Difference between revisions
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sudo htop | sudo htop | ||
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=== Disable swap === | |||
If you have enough free memory, maybe want to reduce writes to the sdcard you can disable the on-disk swap file: | |||
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sudo systemctl stop dphys-swapfile | |||
sudo systemctl disable dphys-swapfile | |||
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Other ways: | |||
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sudo dphys-swapfile swapoff | |||
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Revision as of 11:02, 3 February 2018
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:
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:
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.
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.
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.
Database MySql /MariaDB remote access
See MySQL remote
Performance tuning
Memory
GPU memory
When you are not really using the video capabilities of the Raspberry Pi, the easiest way to obtain some extra memory is to lower the GPU memory, for example to 32 MB. Start config tool:
sudo raspi-config
Then go to 'Advanced' > 'Memory Split' and modify the value
Overview of processes, CPU and memory usage:
sudo htop
Disable swap
If you have enough free memory, maybe want to reduce writes to the sdcard you can disable the on-disk swap file:
sudo systemctl stop dphys-swapfile sudo systemctl disable dphys-swapfile
Other ways:
sudo dphys-swapfile swapoff
Run headless (without desktop) by default
Start config tool:
sudo raspi-config
Configure these options:
- Boot options - Desktop: select text console login
- Interfacing - VNC server: enable
If you now want to start the desktop:
- Set up a VNC client session to the machine
- Login via the text console
- 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
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
