https://wiki.ubuntuusers.de/QR-Code/

qrencode in Ubuntu installieren

> apt install qrencode

Info als QR-Code-Bilddatei ablegen:

> qrencode -o qrcode.png 'Hallo Welt!'

https://github.com/mnooner256/pyqrcode

> cd /usr/ports/graphics/py-pyqrcode && make clean && make config-recursive && make install ; make clean

/usr/local/bin/QR-Code-Generator.py

#!/usr/local/bin/python3.7
 
# graphics/py-pyqrcode
 
import sys
import pyqrcode
 
 
if len(sys.argv) == 1:
        print('Aufruf:')
        print('%s qrcode.png "Die zu kodierende Information."' % sys.argv[0])
else:
        qr = pyqrcode.create(sys.argv[2])
        qr.png(sys.argv[1], scale=5)

> /usr/local/bin/QR-Code-Generator.py qrcode.png "Die zu kodierende Information."
> ls qrcode.png
qrcode.png

zbar in Ubuntu installieren

> apt install zbar-tools

zbar in FreeBSD installieren

> cd /usr/ports/graphics/zbar && make clean && make config-recursive && make install ; make clean

Die QR-Code-Bilddatei lesen (dekodieren):

> zbarimg -q qrcode.png
QR-Code:Hallo Welt!