battery status reporting under i3

battery.sh

#!/bin/bash

# crontab -e
# */10 * * * * DISPLAY=:0.0 ${HOME}/bin/battery.sh

NOW=`echo $((100*$(sed -n "s/remaining capacity: *\(.*\) m[AW]h/\1/p" /proc/acpi/battery/BAT0/state)/$(sed -n "s/last full capacity: *\(.*\) m[AW]h/\1/p" /proc/acpi/battery/BAT0/info)))`
THRESHOLD="30"

if [ $NOW -lt $THRESHOLD ];
then
  /usr/bin/i3-nagbar -m "Battery status critical (below "$THRESHOLD"%)" -b 'pm-suspend' 'sudo pm-suspend' 
  #notify-send "Battery status critical (below "$THRESHOLD"%)"
fi  

#notify-send "Battery status: $NOW%"