BTBL

#! /bin/bash

# bluetooth battery level
# 2022-06-28 01:27:46 - fixes
# 2022-08-01 23:12:38 - show emoji

dev=headset_dev_XX_XX_XX_XX_XX_XX # find it via upower -d
test -n "$1" && dev="$1"
getdata=`upower --show-info "/org/freedesktop/UPower/devices/$dev"`
test -n "`echo "$getdata" | grep '(null)'`" && echo "⊝" && exit
level=`echo "$getdata" | awk '/percentage/{print $2}' | sed 's/%//'`

# check if it's a valid number
case "$level" in
    ''|*[!0-9]*) exit 1;;
esac

# only show emoji for a graphical session
if [ "$TERM" = "dumb" ]; then
    if [ "$level" -gt 39 ]; then # adjust to your situation: below 40% is already too low/little for me
        echo -n " 🔋"
    else
        echo -n " 🪫"
   fi
fi

echo "${level}%"