Battery percentage at your command prompt

#!/bin/bash

#### Declaring colour codes
RESTORE='\033[0m'

RED='\033[00;31m'
LRED='\033[01;31m'
GREEN='\033[00;32m'
LGREEN='\033[01;32m'
YELLOW='\033[00;33m'
LYELLOW='\033[01;33m'


#echo `acpitool | grep -i 'Battery' | awk '{print $5}' | cut -b1-3`
bat_perc=`acpitool | grep -i 'Battery' | awk '{print $5}' | cut -b1-3`
#echo $bat_perc
statusCharge=`acpitool | grep -i 'adapter' | awk '{print $4}'`
#echo $statusCharge
chargeStat=`acpitool | grep -i 'Battery' | awk '{print $4}' | cut -b1`

if [ $statusCharge == 'online' ]
then
    echo -e "${LGREEN}$bat_perc$chargeStat"
elif [[ $statusCharge == 'off-line' && $bat_perc > 80 ]]
then
    echo -e "${GREEN}$bat_perc$chargeStat"
elif [[ $statusCharge == 'off-line' && $bat_perc > 50 && $bat_perc < 79 ]]
then
    echo -e "${LYELLOW}$bat_perc$chargeStat"
elif [[ $statusCharge == 'off-line' && $bat_perc > 30 && $bat_perc < 49 ]]
then
    echo -e "${RED}$bat_perc$chargeStat"
elif [[ $statusCharge == 'off-line' && $bat_perc < 3 && $bat_perc < 29 ]]
then
    echo -e "${LRED}$bat_perc$chargeStat"
fi


Open a text editor and save this under /opt/ or any other directory you want. Add executable permission to this script. You should have acpitool installed for this to work. 

Finally edit your PS1 variable in your .bashrc which will be in your home directory accordingly. Mine is as follows,

PS1='\[\e[01;35m\]\t\[\e[m\]@`/usr/local/bin/bat`\[\e[01;34m\]\w\[\e[m\]\n--> '