Question

If (in zsh) I have an array that contains something like this:

echo ${fsizes[@]}
9.5M 100M 5G 15G 1.2T

is there an easy way to get the sum of these in an output of choice (i.e. bytes, megabytes, gigabytes etc?)

Answer 1

#!/bin/zsh

fsizes=( 9.5M 100M 5G 15G 1.2T )

typeset -A unit
unit=( B 1 K 1024 M 1048576 G 1073741824 T 1099511627776 )

sumSize(){
    sum=0
    for sz; do
        u=${sz//[^BKMGT]/}
        n=${sz//$u/}
        b=${unit[$u]}
        (( sum += b * n ))
    done
    out="${@:(-1)}"
    echo "Sum is $(( sum / ${unit[$out]} )) $out"
}

Example with output in Bytes

$ sumSize ${fsizes[@]} "B"
Sum is 1341003608883.2 B

Example with output in Kilobytes

$ sumSize ${fsizes[@]} "K"
Sum is 1309573836.8 K

Example with output in Megabytes

$ sumSize ${fsizes[@]} "M"
Sum is 1278880.7 M

Example with output in Gigabytes

$ sumSize ${fsizes[@]} "G"
Sum is 1248.90693359375 G

Example with output in Terabytes

$ sumSize ${fsizes[@]} "T"
Sum is 1.2196356773376464 T