This script prints out the battery charge on a Linux (Ubuntu 14.04 Trusty and CentOS7/RHEL7) or OSX Mountain Lion laptop

battery_charge.sh

#!/bin/bash
###############################################################################
# Name         : battery_charge
# Usage        : ./battery_charge
# Description  : This script prints out the battery charge on a Linux (Ubuntu 
#                14.04 Trusty and CentOS7/RHEL7) or OSX Mountain Lion laptop
#
# Last Updated : Thu 23 Oct 2014 01:47:13 PM CDT
#
# Author       : Jose Elera (https://github.com/jelera)
# Credits      : http://www.commandlinefu.com/commands/view/10477/get-osx-battery-percentage
#                http://askubuntu.com/a/490713/31823
#                http://stackoverflow.com/a/17072017/428786
#
# License      : MIT
#                Copyright (c) 2014 Jose Elera Campana
#                Permission is hereby granted, free of charge, to any person
#                obtaining a copy of this software and associated documentation
#                files (the "Software"), to deal in the Software without
#                restriction, including without limitation the rights to use,
#                copy, modify, merge, publish, distribute, sublicense, and/or
#                sell copies of the Software, and to permit persons to whom the
#                Software is furnished to do so, subject to the following
#                conditions:
#
#                The above copyright notice and this permission notice shall be
#                included in all copies or substantial portions of the
#                Software.
#
#                THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
#                KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
#                WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
#                PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
#                COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#                LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
#                OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
#                SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
###############################################################################

# Tested on OSX Mountain Lion, Ubuntu 14.04 Trusty and CentOS/RHEL 7
# For OSX and Linux Support
OS="`uname`"
case $OS in
  'Linux')
	battery_charge=`upower -i $(upower -e | grep BAT) | grep --color=never -E percentage|xargs|cut -d' ' -f2|sed s/%// `
    ;;
  'darwin')
	battery_charge=`pmset -g batt | egrep "([0-9]+\%)" -o | sed s/%//`
    ;;
  *) ;;
esac

# If battery_charge is a float, convert to a Integer
battery_charge=${battery_charge%.*}

# Just a simple comparison to echo the main string
if [ "$battery_charge" -gt 75 ]; then
	echo "♥︎♥︎♥︎ ${battery_charge}%"
elif [ "$battery_charge" -gt 50 ]; then
	echo "♡♥︎♥︎ ${battery_charge}%"
elif [ "$battery_charge" -ge 25 ]; then
	echo "♡♡♥︎ ${battery_charge}%"
elif [ "$battery_charge" -ge 5 ]; then
	echo "♡♡♡ ${battery_charge}%"
else
	echo "✗ ${battery_charge}%"
fi