qrencode
Make a QR Code image
1qrencode 'https://play.google.com/store/apps/details?id=org.briarproject.briar.android' -o "${file}".png
Make a QR Coded message in the terminal
1qrencode -t ansi "Hello World"
Read a QR Code image
1zbarimg ${file}
Show wifi QR code (only with Network Manager)
1nmcli device wifi show-password