yosemite-bluetooth-fix.sh

#!/bin/bash
# Install sleepwatcher
cd /tmp
curl -O http://www.bernhard-baehr.de/sleepwatcher_2.2.tgz
tar -zxvf sleepwatcher_2.2.tgz
cd sleepwatcher_2.2
sudo mkdir -p /usr/local/sbin /usr/local/share/man/man8
sudo cp sleepwatcher /usr/local/sbin
sudo cp sleepwatcher.8 /usr/local/share/man/man8
sudo cp config/de.bernhard-baehr.sleepwatcher-20compatibility.plist /Library/LaunchAgents
sudo cp config/rc.* /etc
cd ..
rm -r sleepwatcher_2.2*

# Add bluetooth script to /etc/rc.wakeup (the script requires root)
sudo tee -a /etc/rc.wakeup <<EOF
kextunload -b com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport
kextload -b com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport
EOF

# Load the agent to start sleepwatcher
sudo launchctl load /Library/LaunchAgents/de.bernhard-baehr.sleepwatcher-20compatibility.plist

Looks like the kextunload commands don't actually work anymore on High Sierra. However, there's a 3rd party command line tool for doing the same thing and it works: https://github.com/toy/blueutil – you can tweak the scripts mentioned here to use blueutil instead, or there's even a full-blown solution (very similar to what we have seen on this page already): https://gist.github.com/ralph-hm/a65840c4f5e439b90170d735a89a863f