Display colored battery charge. Useful for shell prompts.

battery_charge.sh

#!/bin/bash

show_help() {
cat << EOF
Usage: ${0##*/} [-hz] [-b NUM]
Print level of battery charge (1-100) formatted with colors.

    -h      display this help and exit.
    -b NUM  print a NUM bars instead of a number, e.g. '▸▸▸▸▸▸▹▹▹▹'.
    -z      use zsh colors instead of bash. Remember to autoload -U colors && colors in .zshrc.
EOF
}

#bash colors
green='\033[1;32m'
yellow='\033[0;33m'
red='\033[1;31m'
default='\033[0m'

barNumber=0
OPTIND=1
while getopts "hb:z" opt; do
	case "$opt" in
		h)
			show_help
			exit 0
			;;
		b)
			barNumber="$OPTARG"
			;;
		z)  
			green='%{$fg[green]%}'
			yellow='%{$fg[yellow]%}'
			red='%{$fg[red]%}'
			default='%{$reset_color%}'
			;;
		\?)
			show_help >&2
			exit 1
			;;
	esac
done
shift "$((OPTIND-1))"

if [ -e "/sys/class/power_supply/BAT0/capacity" ]
then
	level=$(cat /sys/class/power_supply/BAT0/capacity)
else
	# try the deprecated directory
	if [ -e "/proc/acpi/battery/BAT0/capacity" ]
	then
		level=$(cat /proc/acpi/battery/BAT0/capacity)
	else
		#Battery probably not present (or perhaps in another directory)
		#Just print nothing
		exit 0
fi
fi

if ((level>=70))
then
    color=$green
elif ((level>=30))
then
    color=$yellow
else
    color=$red
fi

if ((barNumber!=0))
then
	filled=$((level*barNumber/100))
	level=''
	for ((i=0; i<$filled; i++)); do level+='▸'; done
	for ((i=$filled; i<$barNumber; i++)); do level+='▹'; done
fi

echo -e ${color}${level}${default}