Animated progress bar of laptop battery in command line

battery

#!/bin/sh
info=`acpi`
level=`echo $info | grep -Eo '[0-9]{,3}%' | tr -d '%'`
msg=`echo $info | sed 's/.*: //g'`

if [ $# = 0 ]
then columns=$((`tput cols` - 2))
else columns=$(( $1 - 2 ))
fi

blocks=$(( (level*columns)/100 ))

if [ $columns -lt 6 ]
then msg=''
elif test $columns -lt ${#msg}
then msg="$level%"
fi

count=${#msg}
span=$(( (columns - count) / 2 ))

printf ' '
if [ $level -lt 10 ]
then printf '\033[48;5;160m'
elif test $level -lt 30
then printf '\033[48;5;214m'
else printf '\033[48;5;34m'
fi

i=0
while [ $i -lt $columns ]
do
  if [ $i -eq $blocks ]; then printf '\033[48;5;235m'; fi

  if [ $i -ge $span -a $(( i - span )) -lt $count ]
  then
    char=`echo $msg | cut -b $(( i - span + 1 ))`
    if [ "$char" != ' ' ]
    then printf '\033[1m%s' `echo $msg | cut -b $(( i - span + 1))`
    else printf ' '
    fi
  else printf ' '
  fi
  i=$(( i + 1))
done

printf '\033[0m\n'
unset info level columns blocks msg span char