bt-proximity: Check if your phone (or any other bluetooth device) is in range.

bt-proximity.sh

#!/bin/bash

# sudoers:
# username ALL = NOPASSWD: /usr/bin/hcitool, /bin/mount
# crontab:
# @reboot ~/Source/dotfiles/tools/bt-proximity
# one-time pairing:
# bt-device -c F0:XX:XX:XX:XX:XX

mkdir -p ~/.local/bt-proximity
sudo mount -t tmpfs none ~/.local/bt-proximity
STATEFILE=~/.local/bt-proximity/state
while true; do
    sudo hcitool info F0:XX:XX:XX:XX:XX >/dev/null 2>&1 && echo 'present' > $STATEFILE || echo 'absent' > $STATEFILE
    sleep 60
done