Automatically disable Wifi when an Ethernet connection (cable) is plugged in on a Mac

com.mine.toggleairport.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.asb.toggleairport</string>
  <key>OnDemand</key>
  <true/>
  <key>ProgramArguments</key>
  <array>
    <string>/Library/Scripts/toggleAirport.sh</string>
  </array>
  <key>WatchPaths</key>
  <array>
    <string>/Library/Preferences/SystemConfiguration</string>
  </array>
</dict>
</plist>

Installation.md

Overview

This is a bash script that will automatically turn your wifi off if you connect your computer to an ethernet connection and turn wifi back on when you unplug your ethernet cable/adapter. If you decide to turn wifi on for whatever reason, it will remember that choice. This was improvised from this mac hint to work with Yosemite, and without hard-coding the adapter names. It's supposed to support growl, but I didn't check that part. I did, however, add OSX notification center support. Feel free to fork and fix any issues you encounter.

Most the credit for these changes go to Dave Holland.

Requirements

• Mac OSX 10+
• Administrator privileges

Installation Instructions

• Copy toggleAirport.sh to /Library/Scripts/
• Run chmod 755 /Library/Scripts/toggleAirport.sh
• Copy com.mine.toggleairport.plist to /Library/LaunchAgents/
• Run chmod 600 /Library/LaunchAgents/com.mine.toggleairport.plist
• Run sudo launchctl load /Library/LaunchAgents/com.mine.toggleairport.plist to start the watcher

Uninstall Instructions

• Run sudo launchctl unload /Library/LaunchAgents/com.mine.toggleairport.plist to stop the watcher
• Delete /Library/Scripts/toggleAirport.sh
• Delete /Library/LaunchAgents/com.mine.toggleairport.plist
• Delete /private/var/tmp/prev_eth_on
• Delete /private/var/tmp/prev_air_on

Misc

To debug, just run: sudo /Library/Scripts/toggleAirport.sh and add echo's wherever you'd like

toggleAirport.sh

#!/bin/bash

function set_airport {

    new_status=$1

    if [ $new_status = "On" ]; then
        /usr/sbin/networksetup -setairportpower $air_name on
        touch /var/tmp/prev_air_on
    else
        /usr/sbin/networksetup -setairportpower $air_name off
        if [ -f "/var/tmp/prev_air_on" ]; then
            rm /var/tmp/prev_air_on
        fi
    fi

}

function growl {

    # Checks whether Growl is installed
    if [ -f "/usr/local/bin/growlnotify" ]; then
        /usr/local/bin/growlnotify -m "$1" -a "AirPort Utility.app"
    else
        osascript -e "display notification \"$1\" with title \"Wifi Toggle\" sound name \"Hero\""
    fi

}

# Set default values
prev_eth_status="Off"
prev_air_status="Off"
eth_status="Off"

# Grab the names of the adapters. We assume here that any ethernet connection name ends in "Ethernet"
eth_names=`networksetup -listnetworkserviceorder | sed -En 's|^\(Hardware Port: .*Ethernet, Device: (en.)\)$|\1|p'`
air_name=`networksetup -listnetworkserviceorder | sed -En 's/^\(Hardware Port: (Wi-Fi|AirPort), Device: (en.)\)$/\2/p'`

# Determine previous ethernet status
# If file prev_eth_on exists, ethernet was active last time we checked
if [ -f "/var/tmp/prev_eth_on" ]; then
    prev_eth_status="On"
fi

# Determine same for AirPort status
# File is prev_air_on
if [ -f "/var/tmp/prev_air_on" ]; then
    prev_air_status="On"
fi

# Check actual current ethernet status
for eth_name in ${eth_names}; do
    if ([ "$eth_name" != "" ] && [ "`ifconfig $eth_name | grep "status: active"`" != "" ]); then
        eth_status="On"
    fi
done

# And actual current AirPort status
air_status=`/usr/sbin/networksetup -getairportpower $air_name | awk '{ print $4 }'`

# If any change has occured. Run external script (if it exists)
if [ "$prev_air_status" != "$air_status" ] || [ "$prev_eth_status" != "$eth_status" ]; then
    if [ -f "./statusChanged.sh" ]; then
        "./statusChanged.sh" "$eth_status" "$air_status" &
    fi
fi

# Determine whether ethernet status changed
if [ "$prev_eth_status" != "$eth_status" ]; then

    if [ "$eth_status" = "On" ]; then
        set_airport "Off"
        growl "Wired network detected. Turning AirPort off."
    else
        set_airport "On"
        growl "No wired network detected. Turning AirPort on."
    fi

# If ethernet did not change
else

    # Check whether AirPort status changed
    # If so it was done manually by user
    if [ "$prev_air_status" != "$air_status" ]; then
    set_airport $air_status

    if [ "$air_status" = "On" ]; then
        growl "AirPort manually turned on."
    else
        growl "AirPort manually turned off."
    fi

    fi

fi

# Update ethernet status
if [ "$eth_status" == "On" ]; then
    touch /var/tmp/prev_eth_on
else
    if [ -f "/var/tmp/prev_eth_on" ]; then
        rm /var/tmp/prev_eth_on
    fi
fi

exit 0

Thanks for the quick reaction.

It does not run on my end as It still bails out with 'Multiple ethernet interfaces match as I have e.g. in the office here multiple Display Ethernet and multiple LAN:

$ networksetup -listnetworkserviceorder | grep -e 'Display Ethernet' -e LAN
(1) Belkin USB-C LAN
(Hardware Port: Belkin USB-C LAN, Device: en8)
(3) Display Ethernet
(Hardware Port: Display Ethernet, Device: en9)
(6) Display Ethernet 2
(Hardware Port: Display Ethernet, Device: en10)
(7) Display Ethernet 3
(Hardware Port: Display Ethernet, Device: en11)
(11) USB 10/100/1G/2.5G LAN
(Hardware Port: USB 10/100/1G/2.5G LAN, Device: en6)

The script output is the following (I'm connecte to ethernet actually:
$ ./wifi-toggle.sh run
DEBUG: get_interface(): regex '(Wi-Fi|Airport)' -> interface 'en0'
DEBUG: Checking ethernet regexes: LAN Ethernet
DEBUG: Trying ethernet regex: 'LAN'
ERROR: Multiple ethernet interfaces match: LAN
DEBUG: No interface found for regex 'LAN'
DEBUG: Trying ethernet regex: 'Ethernet'
ERROR: Multiple ethernet interfaces match: Ethernet
DEBUG: No interface found for regex 'Ethernet'
DEBUG: No active ethernet interfaces found
DEBUG: ethernet status: 'inactive', wifi status: 'inactive'
DEBUG: enabling wifi

Actually I played around aswell with the script and came up with a solution that supports multiple matches with one REGEX and just checks if at least one interface is connected. The script is attached.
The only thing that actually isn't covered properly and should be covered the same way as in your original script is the case if the Wifi REGEX matches more than one interface.

• then we should either bail out
• or turn off all wifi interfaces

I've also added a quick command 'list' to see what interfaces matches the different REGEX to double check if all needed is covered.

My version can be found at https://gist.github.com/keenonkites/9dc158bd63c43f6ff294ed9dd34bea31

Have a look and take whatever snippets you want (if any) for backporting.

Cheers Patrik

Original script didn't work for me initially. Had to change the REGEX for variable eth_names in toggleAirport.sh as my network is connected via usb-c adapter. After this it worked like expected. Thanks a lot!

eth_names="networksetup -listnetworkserviceorder | sed -En 's|^\(Hardware Port: USB 10/100/1000 LAN, Device: (en.)\)$|\1|p'"

My version can be found at https://gist.github.com/keenonkites/9dc158bd63c43f6ff294ed9dd34bea31

The link is dead.

Let's try it with this link again....
https://gist.github.com/keenonkites/9dc158bd63c43f6ff294ed9dd34bea31

(the link was written correct, but a click didn't function as I messed up name and URL)