Randomly select a installed printer on macOS

instruction.sh

# Randomly select a printer every 2 minutes
# This is a simple "load-balancing" printer queue
# Florian Bentele - 2017

# Step 1: Open the Terminal.app (/Applications/Utilities/Terminal.app)
# Check what printer is the Default Printer, enter the following command and hit enter 

lpstat -d

# The output should be something like "system default destination: my_printer1"

# Step 2: Check all printers that may be listed

lpstat -p | awk '{ print $2 }'

# This lists all the printers available, remove any printer you don't want to include in your loadbalancing from the systems preferences

# Step 3: Create a cronjob, that changes the default printer
crontab -l > tempcronjob
echo "*/2 * * * * lpoptions -d \`lpstat -p | awk '{ print $2 }' | ruby -e 'puts STDIN.readlines.shuffle' | head -n 1\` >/dev/null 2>&1" >> tempcronjob
crontab tempcronjob
rm tempcronjob

# Step 4: Test which is the default printer (the result will change ever 2 minutes)
lpstat -d

# To remove / stop the scrippt
crontab -e
# then go to the line where the cronjob is defined and press two times the letter "d"
# press ctrl+c and enter ":wq" and hit enter