simple calculation function for integer *and* floating point math

calculate.bash

# simple calculation function for integer *and* floating point math
#
# @param string to be calculated
# @param precision (default = 0)
# usage: calculate "(1+1)/2/10"     <- outputs 0 
#        calculate "(1+1)/2/10" 10  <- outputs 0.1
#        echo $(calculate "1+1")    <- outputs 2

calculate(){
  if [[ -n "$2" ]]; then
    which bc &>/dev/null && { echo "scale=$2;$1" | bc; } || echo "bc is not installed"; 
  else echo $(($1)); fi
}