Display a QR code on the fly from zsh

You’re typing away at the console in Linux or Mac OS when you suddenly need to display a QR code. There are a lot of dubious websites that purport to generate QR codes for you, but at what cost?

Let’s just generate our own QR codes using open-source tools.

1. Install prerequisites

First, we need to install a few packages.

• qrencode : OSS utility for generating QR codes
• feh : Lightweight OSS X11 image viewer
• xclip : Access the clipboard if you want to generate a QR code from the contents of the clipboard. Only necessary on Linux because Mac has pbpaste built in, which does the same thing.

Linux

If using apt, installation would look something like:

sudo apt install qrencode feh xclip

Mac OS

If you use Homebrew:

brew install qrencode
brew install feh

2. Write a little zsh script

#!/usr/bin/env zsh

# Make sure we have all the utilities we need
requiredBins=('qrencode' 'feh')

if [[ `uname` == "Darwin" ]]; then	
	requiredBins+=("pbpaste")
else
	requiredBins+=("xclip")
fi

missingBins=()

for cmd in $requiredBins
do
	if ! which $cmd > /dev/null; then
		missingBins+=($cmd)	
	fi
done

if [ ${#missingBins[@]} -gt 0 ]; then
	IFS=","
	echo "OOPS! Missing $missingBins"
	exit 1
fi

# Clipboard paste function which works on Mac and Linux
paste() {
	if which pbpaste > /dev/null; then
		pbpaste
	else
		xclip -selection clipboard -o
	fi
}

# Try using the command line argument as the QR source text
sourceText=$1

if (( # == 0 )); then
	# No argument. Grab from clipboard instead
	sourceText=$(paste)	
fi 

# Convert the text to a QR code and display it with feh
echo $sourceText | qrencode --size=15 -o - | feh -

The same script is on GitHub , in case that’s hard to read up there.

3. Execute your script

• Save your new script somewhere like ~/.local/bin/qr
• Make it executable: chmod +x ~/.local/bin/qr
• Run it: qr 'some text'
• Or copy some text to the clipboard and run it with qr

4. Enjoy your nice new QR code

Ahhh. Now that’s a nice QR code. 😎